PostgreSQL 9.x Security Technical Implementation Guide

In order to prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols/services on information systems. Applications are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., email and web services); however, doing so increases risk over limiting the services provided by any one component. To support the requirements and principles of least functionality, the application must support the organizational requirements providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or to address authorized quality of life issues. Database Management Systems using ports, protocols, and services deemed unsafe are open to attack through those ports, protocols, and services. This can allow unauthorized access to the database and through the database to other components of the information system.

Information system auditing capability is critical for accurate forensic analysis. Without information about the outcome of events, security personnel cannot make an accurate assessment as to whether an attack was successful or if changes were made to the security state of the system. Event outcomes can include indicators of event success or failure and event-specific results (e.g., the security state of the information system after the event occurred). As such, they also provide a means to measure the impact of an event and help authorized personnel to determine the appropriate response.

If audit data were to become compromised, then competent forensic analysis and discovery of the true source of potentially malicious system activity is impossible to achieve. To ensure the veracity of audit data the information system and/or the application must protect audit information from unauthorized modification. This requirement can be achieved through multiple methods that will depend upon system architecture and design. Some commonly employed methods include ensuring log files enjoy the proper file system permissions and limiting log data locations. Applications providing a user interface to audit data will leverage user permissions and roles identifying the user accessing the data and the corresponding rights that the user enjoys in order to make access decisions regarding the modification of audit data. Audit information includes all information (e.g., audit records, audit settings, and audit reports) needed to successfully audit information system activity. Modification of database audit data could mask the theft of, or the unauthorized modification of, sensitive data stored in the database.

Enterprise environments make account management for applications and databases challenging and complex. A manual process for account management functions adds the risk of a potential oversight or other error. Managing accounts for the same person in multiple places is inefficient and prone to problems with consistency and synchronization. A comprehensive application account management process that includes automation helps to ensure that accounts designated as requiring attention are consistently and promptly addressed. Examples include, but are not limited to, using automation to take action on multiple accounts designated as inactive, suspended, or terminated, or by disabling accounts located in non-centralized account stores, such as multiple servers. Account management functions can also include: assignment of group or role membership; identifying account type; specifying user access authorizations (i.e., privileges); account removal, update, or termination; and administrative alerts. The use of automated mechanisms can include, for example: using email or text messaging to notify account managers when users are terminated or transferred; using the information system to monitor account usage; and using automated telephone notification to report atypical system account usage. PostgreSQL must be configured to automatically utilize organization-level account management functions, and these functions must immediately enforce the organization's current account policy. Automation may be comprised of differing technologies that when placed together contain an overall mechanism supporting an organization's automated account management requirements.

Any PostgreSQL or associated application providing too much information in error messages on the screen or printout risks compromising the data and security of the system. The structure and content of error messages need to be carefully considered by the organization and development team. Databases can inadvertently provide a wealth of information to an attacker through improperly handled error messages. In addition to sensitive business or personal information, database errors can provide host names, IP addresses, user names, and other system information not required for troubleshooting but very useful to someone targeting the system. Carefully consider the structure/content of error messages. The extent to which information systems are able to identify and handle error conditions is guided by organizational policy and operational requirements. Information that could be exploited by adversaries includes, for example, logon attempts with passwords entered by mistake as the username, mission/business information that can be derived from (if not stated explicitly by) information recorded, and personal information, such as account numbers, social security numbers, and credit card numbers.

If the system were to allow any user to make changes to software libraries, those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. Accordingly, only qualified and authorized individuals must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications. Unmanaged changes that occur to the database software libraries or configuration can lead to unauthorized or compromised installations.

If the system were to allow any user to make changes to software libraries, those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. Accordingly, only qualified and authorized individuals must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications. Unmanaged changes that occur to the database code can lead to unauthorized or compromised installations.

The DoD standard for authentication is DoD-approved PKI certificates. Authentication based on User ID and Password may be used only when it is not possible to employ a PKI certificate, and requires AO approval. In such cases, passwords need to be protected at all times, and encryption is the standard method for protecting passwords during transmission. PostgreSQL passwords sent in clear text format across the network are vulnerable to discovery by unauthorized users. Disclosure of passwords may easily lead to unauthorized access to the database.

Authentication with a DoD-approved PKI certificate does not necessarily imply authorization to access PostgreSQL. To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems, including databases, must be properly configured to implement access control policies. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system. This requirement is applicable to access control enforcement applications, a category that includes database management systems. If PostgreSQL does not follow applicable policy when approving access, it may be in conflict with networks or other applications in the information system. This may result in users either gaining or being denied access inappropriately and in conflict with applicable policy.

Without the association of security labels to information, there is no basis for PostgreSQL to make security-related access-control decisions. Security labels are abstractions representing the basic properties or characteristics of an entity (e.g., subjects and objects) with respect to safeguarding information. These labels are typically associated with internal data structures (e.g., tables, rows) within the database and are used to enable the implementation of access control and flow control policies, reflect special dissemination, handling or distribution instructions, or support other aspects of the information security policy. One example includes marking data as classified or FOUO. These security labels may be assigned manually or during data processing, but, either way, it is imperative these assignments are maintained while the data is in storage. If the security labels are lost when the data is stored, there is the risk of a data compromise.

Database management includes the ability to control the number of users and user sessions utilizing PostgreSQL. Unlimited concurrent connections to PostgreSQL could allow a successful Denial of Service (DoS) attack by exhausting connection resources; and a system can also fail or be degraded by an overload of legitimate users. Limiting the number of concurrent sessions per user is helpful in reducing these risks. This requirement addresses concurrent session control for a single account. It does not address concurrent sessions by a single user via multiple system accounts; and it does not deal with the total number of sessions across all accounts. The capability to limit the number of concurrent sessions per user must be configured in or added to PostgreSQL (for example, by use of a logon trigger), when this is technically feasible. Note that it is not sufficient to limit sessions via a web server or application server alone, because legitimate users and adversaries can potentially connect to PostgreSQL by other means. The organization will need to define the maximum number of concurrent sessions by account type, by account, or a combination thereof. In deciding on the appropriate number, it is important to consider the work requirements of the various types of users. For example, 2 might be an acceptable limit for general users accessing the database via an application; but 10 might be too few for a database administrator using a database management GUI tool, where each query tab and navigation pane may count as a separate session. (Sessions may also be referred to as connections or logons, which for the purposes of this requirement are synonyms.)

If PostgreSQL were to allow any user to make changes to database structure or logic, those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. Accordingly, only qualified and authorized individuals must be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications. Unmanaged changes that occur to the database software libraries or configuration can lead to unauthorized or compromised installations.

Non-organizational users include all information system users other than organizational users, which includes organizational employees or individuals the organization deems to have equivalent status of employees (e.g., contractors, guest researchers, individuals from allied nations). Non-organizational users must be uniquely identified and authenticated for all accesses other than those accesses explicitly identified and documented by the organization when related to the use of anonymous access, such as accessing a web server. Accordingly, a risk assessment is used in determining the authentication needs of the organization. Scalability, practicality, and security are simultaneously considered in balancing the need to ensure ease of use for access to federal information and information systems with the need to protect and adequately mitigate risk to organizational operations, organizational assets, individuals, other organizations, and the Nation.

Without the association of security labels to information, there is no basis for PostgreSQL to make security-related access-control decisions. Security labels are abstractions representing the basic properties or characteristics of an entity (e.g., subjects and objects) with respect to safeguarding information. These labels are typically associated with internal data structures (e.g., tables, rows) within the database and are used to enable the implementation of access control and flow control policies, reflect special dissemination, handling or distribution instructions, or support other aspects of the information security policy. One example includes marking data as classified or FOUO. These security labels may be assigned manually or during data processing, but, either way, it is imperative these assignments are maintained while the data is in storage. If the security labels are lost when the data is stored, there is the risk of a data compromise.

Invalid user input occurs when a user inserts data or characters into an application's data entry fields and the application is unprepared to process that data. This results in unanticipated application behavior, potentially leading to an application or information system compromise. Invalid user input is one of the primary methods employed when attempting to compromise an application. With respect to database management systems, one class of threat is known as SQL Injection, or more generally, code injection. It takes advantage of the dynamic execution capabilities of various programming languages, including dialects of SQL. Potentially, the attacker can gain unauthorized access to data, including security settings, and severely corrupt or destroy the database. Even when no such hijacking takes place, invalid input that gets recorded in the database, whether accidental or malicious, reduces the reliability and usability of the system. Available protections include data types, referential constraints, uniqueness constraints, range checking, and application-specific logic. Application-specific logic can be implemented within the database in stored procedures and triggers, where appropriate. This calls for inspection of application source code, which will require collaboration with the application developers. It is recognized that in many cases, the database administrator (DBA) is organizationally separate from the application developers, and may have limited, if any, access to source code. Nevertheless, protections of this type are so important to the secure operation of databases that they must not be ignored. At a minimum, the DBA must attempt to obtain assurances from the development organization that this issue has been addressed, and must document what has been discovered.

With respect to database management systems, one class of threat is known as SQL Injection, or more generally, code injection. It takes advantage of the dynamic execution capabilities of various programming languages, including dialects of SQL. In such cases, the attacker deduces the manner in which SQL statements are being processed, either from inside knowledge or by observing system behavior in response to invalid inputs. When the attacker identifies scenarios where SQL queries are being assembled by application code (which may be within the database or separate from it) and executed dynamically, the attacker is then able to craft input strings that subvert the intent of the query. Potentially, the attacker can gain unauthorized access to data, including security settings, and severely corrupt or destroy the database. The principal protection against code injection is not to use dynamic execution except where it provides necessary functionality that cannot be utilized otherwise. Use strongly typed data items rather than general-purpose strings as input parameters to task-specific, pre-compiled stored procedures and functions (and triggers). This calls for inspection of application source code, which will require collaboration with the application developers. It is recognized that in many cases, the database administrator (DBA) is organizationally separate from the application developers, and may have limited, if any, access to source code. Nevertheless, protections of this type are so important to the secure operation of databases that they must not be ignored. At a minimum, the DBA must attempt to obtain assurances from the development organization that this issue has been addressed, and must document what has been discovered.

With respect to database management systems, one class of threat is known as SQL Injection, or more generally, code injection. It takes advantage of the dynamic execution capabilities of various programming languages, including dialects of SQL. In such cases, the attacker deduces the manner in which SQL statements are being processed, either from inside knowledge or by observing system behavior in response to invalid inputs. When the attacker identifies scenarios where SQL queries are being assembled by application code (which may be within the database or separate from it) and executed dynamically, the attacker is then able to craft input strings that subvert the intent of the query. Potentially, the attacker can gain unauthorized access to data, including security settings, and severely corrupt or destroy the database. The principal protection against code injection is not to use dynamic execution except where it provides necessary functionality that cannot be utilized otherwise. Use strongly typed data items rather than general-purpose strings as input parameters to task-specific, pre-compiled stored procedures and functions (and triggers). When dynamic execution is necessary, ways to mitigate the risk include the following, which should be implemented both in the on-screen application and at the database level, in the stored procedures: -- Allow strings as input only when necessary. -- Rely on data typing to validate numbers, dates, etc. Do not accept invalid values. If substituting other values for them, think carefully about whether this could be subverted. -- Limit the size of input strings to what is truly necessary. -- If single quotes/apostrophes, double quotes, semicolons, equals signs, angle brackets, or square brackets will never be valid as input, reject them. -- If comment markers will never be valid as input, reject them. In SQL, these are -- or /* */ -- If HTML and XML tags, entities, comments, etc., will never be valid, reject them. -- If wildcards are present, reject them unless truly necessary. In SQL these are the underscore and the percentage sign, and the word ESCAPE is also a clue that wildcards are in use. -- If SQL key words, such as SELECT, INSERT, UPDATE, DELETE, CREATE, ALTER, DROP, ESCAPE, UNION, GRANT, REVOKE, DENY, MODIFY will never be valid, reject them. Use case-insensitive comparisons when searching for these. Bear in mind that some of these words, particularly Grant (as a person's name), could also be valid input. -- If there are range limits on the values that may be entered, enforce those limits. -- Institute procedures for inspection of programs for correct use of dynamic coding, by a party other than the developer. -- Conduct rigorous testing of program modules that use dynamic coding, searching for ways to subvert the intended use. -- Record the inspection and testing in the system documentation. -- Bear in mind that all this applies not only to screen input, but also to the values in an incoming message to a web service or to a stored procedure called by a software component that has not itself been hardened in these ways. Not only can the caller be subject to such vulnerabilities; it may itself be the attacker.

In order to ensure sufficient storage capacity for the audit logs, PostgreSQL must be able to allocate audit record storage capacity. Although another requirement (SRG-APP-000515-DB-000318) mandates that audit data be off-loaded to a centralized log management system, it remains necessary to provide space on the database server to serve as a buffer against outages and capacity limits of the off-loading mechanism. The task of allocating audit record storage capacity is usually performed during initial installation of PostgreSQL and is closely associated with the DBA and system administrator roles. The DBA or system administrator will usually coordinate the allocation of physical drive space with the application owner/installer and the application will prompt the installer to provide the capacity information, the physical location of the disk, or both. In determining the capacity requirements, consider such factors as: total number of users; expected number of concurrent users during busy periods; number and type of events being monitored; types and amounts of data being captured; the frequency/speed with which audit records are off-loaded to the central log management system; and any limitations that exist on PostgreSQL's ability to reuse the space formerly occupied by off-loaded records.

Discretionary Access Control (DAC) is based on the notion that individual users are "owners" of objects and therefore have discretion over who should be authorized to access the object and in which mode (e.g., read or write). Ownership is usually acquired as a consequence of creating the object or via specified ownership assignment. DAC allows the owner to determine who will have access to objects they control. An example of DAC includes user-controlled table permissions. When discretionary access control policies are implemented, subjects are not constrained with regard to what actions they can take with information for which they have already been granted access. Thus, subjects that have been granted access to information are not prevented from passing (i.e., the subjects have the discretion to pass) the information to other subjects or objects. A subject that is constrained in its operation by Mandatory Access Control policies is still able to operate under the less rigorous constraints of this requirement. Thus, while Mandatory Access Control imposes constraints preventing a subject from passing information to another subject operating at a different sensitivity level, this requirement permits the subject to pass the information to any subject at the same sensitivity level. The policy is bounded by the information system boundary. Once the information is passed outside of the control of the information system, additional means may be required to ensure the constraints remain in effect. While the older, more traditional definitions of discretionary access control require identity-based access control, that limitation is not required for this use of discretionary access control.

If audit data were to become compromised, then competent forensic analysis and discovery of the true source of potentially malicious system activity is impossible to achieve. To ensure the veracity of audit data, the information system and/or the application must protect audit information from unauthorized deletion. This requirement can be achieved through multiple methods which will depend upon system architecture and design. Some commonly employed methods include: ensuring log files enjoy the proper file system permissions utilizing file system protections; restricting access; and backing up log data to ensure log data is retained. Applications providing a user interface to audit data will leverage user permissions and roles identifying the user accessing the data and the corresponding rights the user enjoys in order make access decisions regarding the deletion of audit data. Audit information includes all information (e.g., audit records, audit settings, and audit reports) needed to successfully audit information system activity. Deletion of database audit data could mask the theft of, or the unauthorized modification of, sensitive data stored in the database.

If time stamps are not consistently applied and there is no common time reference, it is difficult to perform forensic analysis. Time stamps generated by PostgreSQL must include date and time. Time is commonly expressed in Coordinated Universal Time (UTC), a modern continuation of Greenwich Mean Time (GMT), or local time with an offset from UTC.

If PostgreSQL provides too much information in error logs and administrative messages to the screen, this could lead to compromise. The structure and content of error messages need to be carefully considered by the organization and development team. The extent to which the information system is able to identify and handle error conditions is guided by organizational policy and operational requirements. Some default PostgreSQL error messages can contain information that could aid an attacker in, among others things, identifying the database type, host address, or state of the database. Custom errors may contain sensitive customer information. It is important that detailed error messages be visible only to those who are authorized to view them; that general users receive only generalized acknowledgment that errors have occurred; and that these generalized messages appear only when relevant to the user's task. For example, a message along the lines of, "An error has occurred. Unable to save your changes. If this problem persists, please contact your help desk" would be relevant. A message such as "Warning: your transaction generated a large number of page splits" would likely not be relevant. Administrative users authorized to review detailed error messages typically are the ISSO, ISSM, SA, and DBA. Other individuals or roles may be specified according to organization-specific needs, with DBA approval.

Without the capability to restrict which roles and individuals can select which events are audited, unauthorized personnel may be able to prevent or interfere with the auditing of critical events. Suppression of auditing could permit an adversary to evade detection. Misconfigured audits can degrade the system's performance by overwhelming the audit log. Misconfigured audits may also make it more difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one.

It is critical for the appropriate personnel to be aware if a system is at risk of failing to process audit logs as required. Without a real-time alert, security personnel may be unaware of an impending failure of the audit capability, and system operation may be adversely affected. The appropriate support staff include, at a minimum, the ISSO and the DBA/SA. Alerts provide organizations with urgent messages. Real-time alerts provide these messages immediately (i.e., the time from event detection to alert occurs in seconds or less). The necessary monitoring and alerts may be implemented using features of PostgreSQL, the OS, third-party software, custom code, or a combination of these. The term "the system" is used to encompass all of these.

Information can be either unintentionally or maliciously disclosed or modified during reception, including, for example, during aggregation, at protocol transformation points, and during packing/unpacking. These unauthorized disclosures or modifications compromise the confidentiality or integrity of the information. This requirement applies only to those applications that are either distributed or can allow access to data nonlocally. Use of this requirement will be limited to situations where the data owner has a strict requirement for ensuring data integrity and confidentiality is maintained at every step of the data transfer and handling process. When receiving data, PostgreSQL, associated applications, and infrastructure must leverage protection mechanisms. PostgreSQL uses OpenSSL SSLv23_method() in fe-secure-openssl.c; while the name is misleading, this function enables only TLS encryption methods, not SSL. See OpenSSL: https://mta.openssl.org/pipermail/openssl-dev/2015-May/001449.html

Within the database, object ownership implies full privileges to the owned object, including the privilege to assign access to the owned objects to other subjects. Database functions and procedures can be coded using definer's rights. This allows anyone who utilizes the object to perform the actions if they were the owner. If not properly managed, this can lead to privileged actions being taken by unauthorized individuals. Conversely, if critical tables or other objects rely on unauthorized owner accounts, these objects may be lost when an account is removed.

When dealing with change control issues, it should be noted any changes to the hardware, software, and/or firmware components of the information system and/or application can have significant effects on the overall security of the system. If the system were to allow any user to make changes to software libraries, those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. Accordingly, only qualified and authorized individuals must be allowed access to information system components for purposes of initiating changes, including upgrades and modifications. DBA and other privileged administrative or application owner accounts are granted privileges that allow actions that can have a great impact on database security and operation. It is especially important to grant privileged access to only those persons who are qualified and authorized to use them.

When dealing with change control issues, it should be noted, any changes to the hardware, software, and/or firmware components of the information system and/or application can potentially have significant effects on the overall security of the system. Multiple applications can provide a cumulative negative effect. A vulnerability and subsequent exploit to one application can lead to an exploit of other applications sharing the same security context. For example, an exploit to a web server process that leads to unauthorized administrative access to host system directories can most likely lead to a compromise of all applications hosted by the same system. Database software not installed using dedicated directories both threatens and is threatened by other hosted applications. Access controls defined for one application may by default provide access to the other application's database objects or directories. Any method that provides any level of separation of security context assists in the protection between applications.

Information system auditing capability is critical for accurate forensic analysis. Reconstruction of harmful events or forensic analysis is not possible if audit records do not contain enough information. To support analysis, some types of events will need information to be logged that exceeds the basic requirements of event type, time stamps, location, source, outcome, and user identity. If additional information is not available, it could negatively impact forensic investigations into user actions or other malicious events. The organization must determine what additional information is required for complete analysis of the audited events. The additional information required is dependent on the type of information (e.g., sensitivity of the data and the environment within which it resides). At a minimum, the organization must employ either full-text recording of privileged commands or the individual identities of users of shared accounts, or both. The organization must maintain audit trails in sufficient detail to reconstruct events to determine the cause and impact of compromise. Examples of detailed information the organization may require in audit records are full-text recording of privileged commands or the individual identities of shared account users.

In certain situations, to provide required functionality, PostgreSQL needs to execute internal logic (stored procedures, functions, triggers, etc.) and/or external code modules with elevated privileges. However, if the privileges required for execution are at a higher level than the privileges assigned to organizational users invoking the functionality applications/programs, those users are indirectly provided with greater privileges than assigned by organizations. Privilege elevation must be utilized only where necessary and protected from misuse. This calls for inspection of application source code, which will require collaboration with the application developers. It is recognized that in many cases, the database administrator (DBA) is organizationally separate from the application developers, and may have limited, if any, access to source code. Nevertheless, protections of this type are so important to the secure operation of databases that they must not be ignored. At a minimum, the DBA must attempt to obtain assurances from the development organization that this issue has been addressed, and must document what has been discovered.

A common vulnerability is unplanned behavior when invalid inputs are received. This requirement guards against adverse or unintended system behavior caused by invalid inputs, where information system responses to the invalid input may be disruptive or cause the system to fail into an unsafe state. The behavior will be derived from the organizational and system requirements and includes, but is not limited to, notification of the appropriate personnel, creating an audit record, and rejecting invalid input.

Without the ability to centrally manage the content captured in the audit records, identification, troubleshooting, and correlation of suspicious behavior would be difficult and could lead to a delayed or incomplete analysis of an ongoing attack. The content captured in audit records must be managed from a central location (necessitating automation). Centralized management of audit records and logs provides for efficiency in maintenance and management of records, as well as the backup and archiving of those records. PostgreSQL may write audit records to database tables, to files in the file system, to other kinds of local repository, or directly to a centralized log management system. Whatever the method used, it must be compatible with off-loading the records to the centralized system.

An isolation boundary provides access control and protects the integrity of the hardware, software, and firmware that perform security functions. Security functions are the hardware, software, and/or firmware of the information system responsible for enforcing the system security policy and supporting the isolation of code and data on which the protection is based. Developers and implementers can increase the assurance in security functions by employing well-defined security policy models; structured, disciplined, and rigorous hardware and software development techniques; and sound system/security engineering principles. Database Management Systems typically separate security functionality from non-security functionality via separate databases or schemas. Database objects or code implementing security functionality should not be commingled with objects or code implementing application logic. When security and non-security functionality are commingled, users who have access to non-security functionality may be able to access security functionality.

Without auditing the enforcement of access restrictions against changes to configuration, it would be difficult to identify attempted attacks and an audit trail would not be available for forensic investigation for after-the-fact actions. Enforcement actions are the methods or mechanisms used to prevent unauthorized changes to configuration settings. Enforcement action methods may be as simple as denying access to a file based on the application of file permissions (access restriction). Audit items may consist of lists of actions blocked by access restrictions or changes identified after the fact.

If audit data were to become compromised, then competent forensic analysis and discovery of the true source of potentially malicious system activity is difficult, if not impossible, to achieve. In addition, access to audit records provides information an attacker could potentially use to his or her advantage. To ensure the veracity of audit data, the information system and/or the application must protect audit information from any and all unauthorized access. This includes read, write, copy, etc. This requirement can be achieved through multiple methods which will depend upon system architecture and design. Some commonly employed methods include ensuring log files enjoy the proper file system permissions utilizing file system protections and limiting log data location. Additionally, applications with user interfaces to audit records should not allow for the unfettered manipulation of or access to those records via the application. If the application provides access to the audit data, the application becomes accountable for ensuring that audit information is protected from unauthorized access. Audit information includes all information (e.g., audit records, audit settings, and audit reports) needed to successfully audit information system activity.

Previous versions of PostgreSQL components that are not removed from the information system after updates have been installed may be exploited by adversaries. Some PostgreSQL installation tools may remove older versions of software automatically from the information system. In other cases, manual review and removal will be required. In planning installations and upgrades, organizations must include steps (automated, manual, or both) to identify and remove the outdated modules. A transition period may be necessary when both the old and the new software are required. This should be taken into account in the planning.

Changes in categorized information must be tracked. Without an audit trail, unauthorized access to protected data could go undetected. For detailed information on categorizing information, refer to FIPS Publication 199, Standards for Security Categorization of Federal Information and Information Systems, and FIPS Publication 200, Minimum Security Requirements for Federal Information and Information Systems.

Changes to the security configuration must be tracked. This requirement applies to situations where security data is retrieved or modified via data manipulation operations, as opposed to via specialized security functionality. In an SQL environment, types of access include, but are not necessarily limited to: SELECT INSERT UPDATE DELETE EXECUTE To aid in diagnosis, it is necessary to keep track of failed attempts in addition to the successful ones.

For completeness of forensic analysis, it is necessary to track failed attempts to log on to PostgreSQL. While positive identification may not be possible in a case of failed authentication, as much information as possible about the incident must be captured.

For completeness of forensic analysis, it is necessary to know how long a user's (or other principal's) connection to PostgreSQL lasts. This can be achieved by recording disconnections, in addition to logons/connections, in the audit logs. Disconnection may be initiated by the user or forced by the system (as in a timeout) or result from a system or network failure. To the greatest extent possible, all disconnections must be logged.

Changes in the database objects (tables, views, procedures, functions) that record and control permissions, privileges, and roles granted to users and roles must be tracked. Without an audit trail, unauthorized changes to the security subsystem could go undetected. The database could be severely compromised or rendered inoperative. To aid in diagnosis, it is necessary to keep track of failed attempts in addition to the successful ones.

Changes in the permissions, privileges, and roles granted to users and roles must be tracked. Without an audit trail, unauthorized elevation or restriction of privileges could go undetected. Elevated privileges give users access to information and functionality that they should not have; restricted privileges wrongly deny access to authorized users. In an SQL environment, adding permissions is typically done via the GRANT command, or, in the negative, the REVOKE command.

Changes in categorized information must be tracked. Without an audit trail, unauthorized access to protected data could go undetected. To aid in diagnosis, it is necessary to keep track of failed attempts in addition to the successful ones. For detailed information on categorizing information, refer to FIPS Publication 199, Standards for Security Categorization of Federal Information and Information Systems, and FIPS Publication 200, Minimum Security Requirements for Federal Information and Information Systems.

For completeness of forensic analysis, it is necessary to track who/what (a user or other principal) logs on to PostgreSQL.

The removal of security objects from the database/PostgreSQL would seriously degrade a system's information assurance posture. If such an event occurs, it must be logged.

Under some circumstances, it may be useful to monitor who/what is reading privilege/permission/role information. Therefore, it must be possible to configure auditing to do this. PostgreSQLs typically make such information available through views or functions. This requirement addresses explicit requests for privilege/permission/role membership information. It does not refer to the implicit retrieval of privileges/permissions/role memberships that PostgreSQL continually performs to determine if any and every action on the database is permitted. To aid in diagnosis, it is necessary to keep track of failed attempts in addition to the successful ones.

Failed attempts to change the permissions, privileges, and roles granted to users and roles must be tracked. Without an audit trail, unauthorized attempts to elevate or restrict privileges could go undetected. In an SQL environment, deleting permissions is typically done via the REVOKE command. To aid in diagnosis, it is necessary to keep track of failed attempts in addition to the successful ones.

Under some circumstances, it may be useful to monitor who/what is reading privilege/permission/role information. Therefore, it must be possible to configure auditing to do this. PostgreSQLs typically make such information available through views or functions. This requirement addresses explicit requests for privilege/permission/role membership information. It does not refer to the implicit retrieval of privileges/permissions/role memberships that PostgreSQL continually performs to determine if any and every action on the database is permitted.

Changes in categorized information must be tracked. Without an audit trail, unauthorized access to protected data could go undetected. To aid in diagnosis, it is necessary to keep track of failed attempts in addition to the successful ones. For detailed information on categorizing information, refer to FIPS Publication 199, Standards for Security Categorization of Federal Information and Information Systems, and FIPS Publication 200, Minimum Security Requirements for Federal Information and Information Systems.

Without tracking all or selected types of access to all or selected objects (tables, views, procedures, functions, etc.), it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. In an SQL environment, types of access include, but are not necessarily limited to: SELECT INSERT UPDATE DROP EXECUTE To aid in diagnosis, it is necessary to keep track of failed attempts in addition to the successful ones.

Without tracking privileged activity, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. System documentation should include a definition of the functionality considered privileged. A privileged function in this context is any operation that modifies the structure of the database, its built-in logic, or its security settings. This would include all Data Definition Language (DDL) statements and all security-related statements. In an SQL environment, it encompasses, but is not necessarily limited to: CREATE ALTER DROP GRANT REVOKE There may also be Data Manipulation Language (DML) statements that, subject to context, should be regarded as privileged. Possible examples in SQL include: TRUNCATE TABLE, DELETE, or DELETE affecting more than n rows, for some n, or DELETE without a WHERE clause. UPDATE or UPDATE affecting more than n rows, for some n, or UPDATE without a WHERE clause. Any SELECT, INSERT, UPDATE, or DELETE to an application-defined security table executed by other than a security principal. Depending on the capabilities of PostgreSQL and the design of the database and associated applications, audit logging may be achieved by means of DBMS auditing features, database triggers, other mechanisms, or a combination of these. Note: That it is particularly important to audit, and tightly control, any action that weakens the implementation of this requirement itself, since the objective is to have a complete audit trail of all administrative activity.

Changes in categorized information must be tracked. Without an audit trail, unauthorized access to protected data could go undetected. To aid in diagnosis, it is necessary to keep track of failed attempts in addition to the successful ones. For detailed information on categorizing information, refer to FIPS Publication 199, Standards for Security Categorization of Federal Information and Information Systems, and FIPS Publication 200, Minimum Security Requirements for Federal Information and Information Systems.

Changes to the security configuration must be tracked. This requirement applies to situations where security data is retrieved or modified via data manipulation operations, as opposed to via specialized security functionality. In an SQL environment, types of access include, but are not necessarily limited to: CREATE SELECT INSERT UPDATE DELETE PREPARE EXECUTE ALTER DROP

Changes in the permissions, privileges, and roles granted to users and roles must be tracked. Without an audit trail, unauthorized elevation or restriction of privileges could go undetected. Elevated privileges give users access to information and functionality that they should not have; restricted privileges wrongly deny access to authorized users. In an SQL environment, deleting permissions is typically done via the REVOKE command.

For completeness of forensic analysis, it is necessary to track who logs on to PostgreSQL. Concurrent connections by the same user from multiple workstations may be valid use of the system; or such connections may be due to improper circumvention of the requirement to use the CAC for authentication; or they may indicate unauthorized account sharing; or they may be because an account has been compromised. (If the fact of multiple, concurrent logons by a given user can be reliably reconstructed from the log entries for other events (logons/connections; voluntary and involuntary disconnections), then it is not mandatory to create additional log entries specifically for this.)

The removal of security objects from the database/PostgreSQL would seriously degrade a system's information assurance posture. If such an action is attempted, it must be logged. To aid in diagnosis, it is necessary to keep track of failed attempts in addition to the successful ones.

Changes in the permissions, privileges, and roles granted to users and roles must be tracked. Without an audit trail, unauthorized elevation or restriction of privileges could go undetected. Elevated privileges give users access to information and functionality that they should not have; restricted privileges wrongly deny access to authorized users. In an SQL environment, modifying permissions is typically done via the GRANT and REVOKE commands.

Without tracking privileged activity, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. System documentation should include a definition of the functionality considered privileged. A privileged function in this context is any operation that modifies the structure of the database, its built-in logic, or its security settings. This would include all Data Definition Language (DDL) statements and all security-related statements. In an SQL environment, it encompasses, but is not necessarily limited to: CREATE ALTER DROP GRANT REVOKE Note: That it is particularly important to audit, and tightly control, any action that weakens the implementation of this requirement itself, since the objective is to have a complete audit trail of all administrative activity. To aid in diagnosis, it is necessary to keep track of failed attempts in addition to the successful ones.

Changes in the database objects (tables, views, procedures, functions) that record and control permissions, privileges, and roles granted to users and roles must be tracked. Without an audit trail, unauthorized changes to the security subsystem could go undetected. The database could be severely compromised or rendered inoperative.

Changes in categorized information must be tracked. Without an audit trail, unauthorized access to protected data could go undetected. For detailed information on categorizing information, refer to FIPS Publication 199, Standards for Security Categorization of Federal Information and Information Systems, and FIPS Publication 200, Minimum Security Requirements for Federal Information and Information Systems.

Failed attempts to change the permissions, privileges, and roles granted to users and roles must be tracked. Without an audit trail, unauthorized attempts to elevate or restrict privileges could go undetected. Modifying permissions is done via the GRANT and REVOKE commands. To aid in diagnosis, it is necessary to keep track of failed attempts in addition to the successful ones.

Failed attempts to change the permissions, privileges, and roles granted to users and roles must be tracked. Without an audit trail, unauthorized attempts to elevate or restrict privileges could go undetected. In an SQL environment, adding permissions is typically done via the GRANT command, or, in the negative, the REVOKE command. To aid in diagnosis, it is necessary to keep track of failed attempts in addition to the successful ones.

The DoD standard for authentication is DoD-approved PKI certificates. A certificate’s certification path is the path from the end entity certificate to a trusted root certification authority (CA). Certification path validation is necessary for a relying party to make an informed decision regarding acceptance of an end entity certificate. Certification path validation includes checks such as certificate issuer trust, time validity and revocation status for each certificate in the certification path. Revocation status information for CA and subject certificates in a certification path is commonly provided via certificate revocation lists (CRLs) or online certificate status protocol (OCSP) responses. Database Management Systems that do not validate certificates by performing RFC 5280-compliant certification path validation are in danger of accepting certificates that are invalid and/or counterfeit. This could allow unauthorized access to the database.

Information can be either unintentionally or maliciously disclosed or modified during preparation for transmission, including, for example, during aggregation, at protocol transformation points, and during packing/unpacking. These unauthorized disclosures or modifications compromise the confidentiality or integrity of the information. Use of this requirement will be limited to situations where the data owner has a strict requirement for ensuring data integrity and confidentiality is maintained at every step of the data transfer and handling process. When transmitting data, PostgreSQL, associated applications, and infrastructure must leverage transmission protection mechanisms. PostgreSQL uses OpenSSL SSLv23_method() in fe-secure-openssl.c, while the name is misleading, this function enables only TLS encryption methods, not SSL. See OpenSSL: https://mta.openssl.org/pipermail/openssl-dev/2015-May/001449.html

Without the capability to generate audit records, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within PostgreSQL (e.g., process, module). Certain specific application functionalities may be audited as well. The list of audited events is the set of events for which audits are to be generated. This set of events is typically a subset of the list of all events for which the system is capable of generating audit records. DoD has defined the list of events for which PostgreSQL will provide an audit record generation capability as the following: (i) Successful and unsuccessful attempts to access, modify, or delete privileges, security objects, security levels, or categories of information (e.g., classification levels); (ii) Access actions, such as successful and unsuccessful logon attempts, privileged activities, or other system-level access, starting and ending time for user access to the system, concurrent logons from different workstations, successful and unsuccessful accesses to objects, all program initiations, and all direct access to the information system; and (iii) All account creation, modification, disabling, and termination actions. Organizations may define additional events requiring continuous or ad hoc auditing.

Without sufficient granularity of time stamps, it is not possible to adequately determine the chronological order of records. Time stamps generated by PostgreSQL must include date and time. Granularity of time measurements refers to the precision available in time stamp values. Granularity coarser than one second is not sufficient for audit trail purposes. Time stamp values are typically presented with three or more decimal places of seconds; however, the actual granularity may be coarser than the apparent precision. For example, PostgreSQL will always return at least millisecond timestamps but it can be truncated using EXTRACT functions: SELECT EXTRACT(MINUTE FROM TIMESTAMP '2001-02-16 20:38:40');.

Information system auditing capability is critical for accurate forensic analysis. Without information that establishes the identity of the subjects (i.e., users or processes acting on behalf of users) associated with the events, security personnel cannot determine responsibility for the potentially harmful event. Identifiers (if authenticated or otherwise known) include, but are not limited to, user database tables, primary key values, user names, or process identifiers. 1) Linux's sudo and su feature enables a user (with sufficient OS privileges) to emulate another user, and it is the identity of the emulated user that is seen by PostgreSQL and logged in the audit trail. Therefore, care must be taken (outside of Postgresql) to restrict sudo/su to the minimum set of users necessary. 2) PostgreSQL's SET ROLE feature enables a user (with sufficient PostgreSQL privileges) to emulate another user running statements under the permission set of the emulated user. In this case, it is the emulating user's identity, and not that of the emulated user, that gets logged in the audit trail. While this is definitely better than the other way around, ideally, both identities would be recorded.

Use of weak or untested encryption algorithms undermines the purposes of utilizing encryption to protect data. The application must implement cryptographic modules adhering to the higher standards approved by the federal government since this provides assurance they have been tested and validated. It is the responsibility of the data owner to assess the cryptography requirements in light of applicable federal laws, Executive Orders, directives, policies, regulations, and standards. NSA-approved cryptography for classified networks is hardware based. This requirement addresses the compatibility of PostgreSQL with the encryption devices.

This control is intended to address the confidentiality and integrity of information at rest in non-mobile devices and covers user information and system information. Information at rest refers to the state of information when it is located on a secondary storage device (e.g., disk drive, tape drive) within an organizational information system. Applications and application users generate information throughout the course of their application use. User data generated, as well as application-specific configuration data, needs to be protected. Organizations may choose to employ different mechanisms to achieve confidentiality and integrity protections, as appropriate. If the confidentiality and integrity of application data is not protected, the data will be open to compromise and unauthorized modification.

Allowing regular users to install software, without explicit privileges, creates the risk that untested or potentially malicious software will be installed on the system. Explicit privileges (escalated or administrative privileges) provide the regular user with explicit capabilities and control that exceed the rights of a regular user. PostgreSQL functionality and the nature and requirements of databases will vary; so while users are not permitted to install unapproved software, there may be instances where the organization allows the user to install approved software packages such as from an approved software repository. The requirements for production servers will be more restrictive than those used for development and research. PostgreSQL must enforce software installation by users based upon what types of software installations are permitted (e.g., updates and security patches to existing software) and what types of installations are prohibited (e.g., software whose pedigree with regard to being potentially malicious is unknown or suspect) by the organization). In the case of a database management system, this requirement covers stored procedures, functions, triggers, views, etc.

Information system management functionality includes functions necessary to administer databases, network components, workstations, or servers and typically requires privileged user access. The separation of user functionality from information system management functionality is either physical or logical and is accomplished by using different computers, different central processing units, different instances of the operating system, different network addresses, combinations of these methods, or other methods, as appropriate. An example of this type of separation is observed in web administrative interfaces that use separate authentication methods for users of any other information system resources. This may include isolating the administrative interface on a different domain and with additional access controls. If administrative functionality or information regarding PostgreSQL management is presented on an interface available for users, information on DBMS settings may be inadvertently made available to the user.

Session auditing is for use when a user's activities are under investigation. To be sure of capturing all activity during those periods when session auditing is in use, it needs to be in operation for the whole time PostgreSQL is running.

PostgreSQLs handling data requiring "data at rest" protections must employ cryptographic mechanisms to prevent unauthorized disclosure and modification of the information at rest. These cryptographic mechanisms may be native to PostgreSQL or implemented via additional software or operating system/file system settings, as appropriate to the situation. Selection of a cryptographic mechanism is based on the need to protect the integrity of organizational information. The strength of the mechanism is commensurate with the security category and/or classification of the information. Organizations have the flexibility to either encrypt all information on storage devices (i.e., full disk encryption) or encrypt specific data structures (e.g., files, records, or fields). The decision whether and what to encrypt rests with the data owner and is also influenced by the physical measures taken to secure the equipment and media on which the information resides.

Information system auditing capability is critical for accurate forensic analysis. Without establishing the source of the event, it is impossible to establish, correlate, and investigate the events relating to an incident. In order to compile an accurate risk assessment and provide forensic analysis, it is essential for security personnel to know where events occurred, such as application components, modules, session identifiers, filenames, host names, and functionality. In addition to logging where events occur within the application, the application must also produce audit records that identify the application itself as the source of the event. Associating information about the source of the event within the application provides a means of investigating an attack; recognizing resource utilization or capacity thresholds; or identifying an improperly configured application.

Information systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions).  It is detrimental for software products to provide, or install by default, functionality exceeding requirements or mission objectives.   PostgreSQL must adhere to the principles of least functionality by providing only essential capabilities.

Information systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). It is detrimental for applications to provide, or install by default, functionality exceeding requirements or mission objectives. Applications must adhere to the principles of least functionality by providing only essential capabilities. PostgreSQLs may spawn additional external processes to execute procedures that are defined in PostgreSQL but stored in external host files (external procedures). The spawned process used to execute the external procedure may operate within a different OS security context than PostgreSQL and provide unauthorized access to the host system.

Information systems are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions).   It is detrimental for software products to provide, or install by default, functionality exceeding requirements or mission objectives.   PostgreSQL must adhere to the principles of least functionality by providing only essential capabilities.  Unused, unnecessary PostgreSQL components increase the attack vector for PostgreSQL by introducing additional targets for attack. By minimizing the services and applications installed on the system, the number of potential vulnerabilities is reduced. Components of the system that are unused and cannot be uninstalled must be disabled. The techniques available for disabling components will vary by DBMS product, OS and the nature of the component and may include DBMS configuration settings, OS service settings, OS file access security, and DBMS user/role permissions.

Without the association of security labels to information, there is no basis for PostgreSQL to make security-related access-control decisions. Security labels are abstractions representing the basic properties or characteristics of an entity (e.g., subjects and objects) with respect to safeguarding information. These labels are typically associated with internal data structures (e.g., tables, rows) within the database and are used to enable the implementation of access control and flow control policies, reflect special dissemination, handling or distribution instructions, or support other aspects of the information security policy. One example includes marking data as classified or FOUO. These security labels may be assigned manually or during data processing, but, either way, it is imperative these assignments are maintained while the data is in storage. If the security labels are lost when the data is stored, there is the risk of a data compromise. The mechanism used to support security labeling may be the sepgsql feature of PostgreSQL, a third-party product, or custom application code.

The DoD standard for authentication is DoD-approved PKI certificates. Authentication based on User ID and Password may be used only when it is not possible to employ a PKI certificate, and requires AO approval. In such cases, database passwords stored in clear text, using reversible encryption, or using unsalted hashes would be vulnerable to unauthorized disclosure. Database passwords must always be in the form of one-way, salted hashes when stored internally or externally to PostgreSQL.

Failure to provide logical access restrictions associated with changes to configuration may have significant effects on the overall security of the system. When dealing with access restrictions pertaining to change control, it should be noted that any changes to the hardware, software, and/or firmware components of the information system can potentially have significant effects on the overall security of the system. Accordingly, only qualified and authorized individuals should be allowed to obtain access to system components for the purposes of initiating changes, including upgrades and modifications.

Non-repudiation of actions taken is required in order to maintain data integrity. Examples of particular actions taken by individuals include creating information, sending a message, approving information (e.g., indicating concurrence or signing a contract), and receiving a message. Non-repudiation protects against later claims by a user of not having created, modified, or deleted a particular data item or collection of data in the database. In designing a database, the organization must define the types of data and the user actions that must be protected from repudiation. The implementation must then include building audit features into the application data tables, and configuring PostgreSQL' audit tools to capture the necessary audit trail. Design and implementation also must ensure that applications pass individual user identification to PostgreSQL, even where the application connects to PostgreSQL with a standard, shared account.

Without the capability to capture, record, and log all content related to a user session, investigations into suspicious user activity would be hampered. Typically, this PostgreSQL capability would be used in conjunction with comparable monitoring of a user's online session, involving other software components such as operating systems, web servers and front-end user applications. The current requirement, however, deals specifically with PostgreSQL.

Organizations are required to use a central log management system, so, under normal conditions, the audit space allocated to PostgreSQL on its own server will not be an issue. However, space will still be required on PostgreSQL server for audit records in transit, and, under abnormal conditions, this could fill up. Since a requirement exists to halt processing upon audit failure, a service outage would result. If support personnel are not notified immediately upon storage volume utilization reaching 75%, they are unable to plan for storage capacity expansion. The appropriate support staff include, at a minimum, the ISSO and the DBA/SA.

If authorized individuals do not have the ability to modify auditing parameters in response to a changing threat environment, the organization may not be able to effectively respond, and important forensic information may be lost. This requirement enables organizations to extend or limit auditing as necessary to meet organizational requirements. Auditing that is limited to conserve information system resources may be extended to address certain threat situations. In addition, auditing may be limited to a specific set of events to facilitate audit reduction, analysis, and reporting. Organizations can establish time thresholds in which audit actions are changed, for example, near real time, within minutes, or within hours.

The DoD standard for authentication of an interactive user is the presentation of a Common Access Card (CAC) or other physical token bearing a valid, current, DoD-issued Public Key Infrastructure (PKI) certificate, coupled with a Personal Identification Number (PIN) to be entered by the user at the beginning of each session and whenever reauthentication is required. Without reauthentication, users may access resources or perform tasks for which they do not have authorization. When applications provide the capability to change security roles or escalate the functional capability of the application, it is critical the user re-authenticate. In addition to the reauthentication requirements associated with session locks, organizations may require reauthentication of individuals and/or devices in other situations, including (but not limited to) the following circumstances: (i) When authenticators change; (ii) When roles change; (iii) When security categorized information systems change; (iv) When the execution of privileged functions occurs; (v) After a fixed period of time; or (vi) Periodically. Within the DoD, the minimum circumstances requiring reauthentication are privilege escalation and role changes.

Only DoD-approved external PKIs have been evaluated to ensure that they have security controls and identity vetting procedures in place which are sufficient for DoD systems to rely on the identity asserted in the certificate. PKIs lacking sufficient security controls and identity vetting procedures risk being compromised and issuing certificates that enable adversaries to impersonate legitimate users. The authoritative list of DoD-approved PKIs is published at http://iase.disa.mil/pki-pke/interoperability. This requirement focuses on communications protection for PostgreSQL session rather than for the network packet.

Information system auditing capability is critical for accurate forensic analysis. Without establishing what type of event occurred, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit record content that may be necessary to satisfy the requirement of this policy includes, for example, time stamps, user/process identifiers, event descriptions, success/fail indications, filenames involved, and access control or flow control rules invoked. Associating event types with detected events in the application and audit logs provides a means of investigating an attack; recognizing resource utilization or capacity thresholds; or identifying an improperly configured application. Database software is capable of a range of actions on data stored within the database. It is important, for accurate forensic analysis, to know exactly what actions were performed. This requires specific information regarding the event type an audit record is referring to. If event type information is not recorded and stored with the audit record, the record itself is of very limited use.

PostgreSQLs handling data requiring "data at rest" protections must employ cryptographic mechanisms to prevent unauthorized disclosure and modification of the information at rest. These cryptographic mechanisms may be native to PostgreSQL or implemented via additional software or operating system/file system settings, as appropriate to the situation. Selection of a cryptographic mechanism is based on the need to protect the integrity of organizational information. The strength of the mechanism is commensurate with the security category and/or classification of the information. Organizations have the flexibility to either encrypt all information on storage devices (i.e., full disk encryption) or encrypt specific data structures (e.g., files, records, or fields). The decision whether and what to encrypt rests with the data owner and is also influenced by the physical measures taken to secure the equipment and media on which the information resides.

Captured sessions can be reused in "replay" attacks. This requirement limits the ability of adversaries to capture and continue to employ previously valid session IDs. This requirement focuses on communications protection for PostgreSQL session rather than for the network packet. The intent of this control is to establish grounds for confidence at each end of a communications session in the ongoing identity of the other party and in the validity of the information being transmitted. Session IDs are tokens generated by PostgreSQLs to uniquely identify a user's (or process's) session. DBMSs will make access decisions and execute logic based on the session ID. Unique session IDs help to reduce predictability of said identifiers. Unique session IDs address man-in-the-middle attacks, including session hijacking or insertion of false information into a session. If the attacker is unable to identify or guess the session information related to pending application traffic, they will have more difficulty in hijacking the session or otherwise manipulating valid sessions. When a user logs out, or when any other session termination event occurs, PostgreSQL must terminate the user session(s) to minimize the potential for sessions to be hijacked.

Protecting audit data also includes identifying and protecting the tools used to view and manipulate log data. Depending upon the log format and application, system and application log tools may provide the only means to manipulate and manage application and system log data. It is, therefore, imperative that access to audit tools be controlled and protected from unauthorized access. Applications providing tools to interface with audit data will leverage user permissions and roles identifying the user accessing the tools and the corresponding rights the user enjoys in order make access decisions regarding the access to audit tools. Audit tools include, but are not limited to, OS-provided audit tools, vendor-provided audit tools, and open source audit tools needed to successfully view and manipulate audit information system activity and records. If an attacker were to gain access to audit tools, he could analyze audit logs for system weaknesses or weaknesses in the auditing itself. An attacker could also manipulate logs to hide evidence of malicious activity.

Information system auditing capability is critical for accurate forensic analysis. Without establishing when events occurred, it is impossible to establish, correlate, and investigate the events relating to an incident. In order to compile an accurate risk assessment and provide forensic analysis, it is essential for security personnel to know the date and time when events occurred. Associating the date and time with detected events in the application and audit logs provides a means of investigating an attack; recognizing resource utilization or capacity thresholds; or identifying an improperly configured application. Database software is capable of a range of actions on data stored within the database. It is important, for accurate forensic analysis, to know exactly when specific actions were performed. This requires the date and time an audit record is referring to. If date and time information is not recorded and stored with the audit record, the record itself is of very limited use.

Protecting audit data also includes identifying and protecting the tools used to view and manipulate log data. Therefore, protecting audit tools is necessary to prevent unauthorized operation on audit data. Applications providing tools to interface with audit data will leverage user permissions and roles identifying the user accessing the tools and the corresponding rights the user enjoys in order make access decisions regarding the deletion of audit tools. Audit tools include, but are not limited to, vendor-provided and open source audit tools needed to successfully view and manipulate audit information system activity and records. Audit tools include custom queries and report generators.

Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Off-loading is a common process in information systems with limited audit storage capacity. PostgreSQL may write audit records to database tables, to files in the file system, to other kinds of local repository, or directly to a centralized log management system. Whatever the method used, it must be compatible with off-loading the records to the centralized system.

One class of man-in-the-middle, or session hijacking, attack involves the adversary guessing at valid session identifiers based on patterns in identifiers already known. The preferred technique for thwarting guesses at Session IDs is the generation of unique session identifiers using a FIPS 140-2 approved random number generator. However, it is recognized that available PostgreSQL products do not all implement the preferred technique yet may have other protections against session hijacking. Therefore, other techniques are acceptable, provided they are demonstrated to be effective.

To assure accountability and prevent unauthenticated access, organizational users must be identified and authenticated to prevent potential misuse and compromise of the system. Organizational users include organizational employees or individuals the organization deems to have equivalent status of employees (e.g., contractors). Organizational users (and any processes acting on behalf of users) must be uniquely identified and authenticated for all accesses, except the following: (i) Accesses explicitly identified and documented by the organization. Organizations document specific user actions that can be performed on the information system without identification or authentication; and (ii) Accesses that occur through authorized use of group authenticators without individual authentication. Organizations may require unique identification of individuals using shared accounts, for detailed accountability of individual activity.

This addresses the termination of user-initiated logical sessions in contrast to the termination of network connections that are associated with communications sessions (i.e., network disconnect). A logical session (for local, network, and remote access) is initiated whenever a user (or process acting on behalf of a user) accesses an organizational information system. Such user sessions can be terminated (and thus terminate user access) without terminating network sessions. Session termination ends all processes associated with a user's logical session except those batch processes/jobs that are specifically created by the user (i.e., session owner) to continue after the session is terminated. Conditions or trigger events requiring automatic session termination can include, for example, organization-defined periods of user inactivity, targeted responses to certain types of incidents, and time-of-day restrictions on information system use. This capability is typically reserved for specific cases where the system owner, data owner, or organization requires additional assurance.

The DoD standard for authentication is DoD-approved PKI certificates. Once a PKI certificate has been validated, it must be mapped to PostgreSQL user account for the authenticated identity to be meaningful to PostgreSQL and useful for authorization decisions.

Applications, including PostgreSQL, must prevent unauthorized and unintended information transfer via shared system resources.   Data used for the development and testing of applications often involves copying data from production. It is important that specific procedures exist for this process, to include the conditions under which such transfer may take place, where the copies may reside, and the rules for ensuring sensitive data are not exposed.  Copies of sensitive data must not be misplaced or left in a temporary location without the proper controls.

Applications, including PostgreSQL, must prevent unauthorized and unintended information transfer via shared system resources. Permitting only DBMS processes and authorized, administrative users to have access to the files where the database resides helps ensure that those files are not shared inappropriately and are not open to backdoor access and manipulation.

Protecting audit data also includes identifying and protecting the tools used to view and manipulate log data. Therefore, protecting audit tools is necessary to prevent unauthorized operation on audit data. Applications providing tools to interface with audit data will leverage user permissions and roles identifying the user accessing the tools and the corresponding rights the user enjoys in order make access decisions regarding the modification of audit tools. Audit tools include, but are not limited to, vendor-provided and open source audit tools needed to successfully view and manipulate audit information system activity and records. Audit tools include custom queries and report generators.

Changes in categorized information must be tracked. Without an audit trail, unauthorized access to protected data could go undetected. For detailed information on categorizing information, refer to FIPS Publication 199, Standards for Security Categorization of Federal Information and Information Systems, and FIPS Publication 200, Minimum Security Requirements for Federal Information and Information Systems.

Without tracking all or selected types of access to all or selected objects (tables, views, procedures, functions, etc.), it would be difficult to establish, correlate, and investigate the events relating to an incident, or identify those responsible for one. In an SQL environment, types of access include, but are not necessarily limited to: SELECT INSERT UPDATE DELETE EXECUTE

In this context, direct access is any query, command, or call to the DBMS that comes from any source other than the application(s) that it supports. Examples would be the command line or a database management utility program. The intent is to capture all activity from administrative and non-standard sources.

Information system auditing capability is critical for accurate forensic analysis. Without establishing where events occurred, it is impossible to establish, correlate, and investigate the events relating to an incident. In order to compile an accurate risk assessment and provide forensic analysis, it is essential for security personnel to know where events occurred, such as application components, modules, session identifiers, filenames, host names, and functionality. Associating information about where the event occurred within the application provides a means of investigating an attack; recognizing resource utilization or capacity thresholds; or identifying an improperly configured application.