EDB Postgres Advanced Server v11 on Windows Security Technical Implementation Guide

Database management includes the ability to control the number of users and user sessions utilizing a DBMS. Unlimited concurrent connections to the DBMS could allow a successful Denial of Service (DoS) attack by exhausting connection resources; 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, the DBMS (for example, by use of a logon trigger), when this is technically feasible. Note: it is not sufficient to limit sessions via a web server or application server alone, because legitimate users and adversaries can potentially connect to the DBMS 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, two might be an acceptable limit for general users accessing the database via an application; but ten 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.) Note that by default if no connection limit is specified, when a Postgres database user is created it will be allowed to have an unlimited number of concurrent sessions. The EDB Postgres CREATE USER and the PostgreSQL CREATE ROLE sql commands, which are used to create database users, provide a CONNECTION LIMIT option for configuring the allowable number of concurrent sessions for a user. It is good administrative practice to use this option to set the connection limit when new users are created. However, if a user was created without a connection limit or if the assigned connection limit needs to be changed, the CONNECTION LIMIT option can be set using the ALTER USER and ALTER ROLE commands.

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 the DBMS' audit tools to capture the necessary audit trail. Design and implementation also must ensure that applications pass individual user identification to the DBMS, even where the application connects to the DBMS with a standard, group account.

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 the DBMS (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 the DBMS 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 the capability to restrict the types of roles and individuals that 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.

The EDB Postgres Advanced Server must generate audit records for DoD-defined auditable events within all DBMS/database components. Audit records should contain (at a minimum): -Time stamps to establish when the events occurred -Sufficient information to establish what type of events occurred -Sufficient information to establish where the events occurred -Sufficient information to establish the sources (origins) of the events -Sufficient information to establish the outcome (success or failure) of the events -Sufficient information to establish the identity of any user/subject or process associated with the event Audit record content which may be necessary to investigate the events relating to an incident or identify those responsible for one. Audit policy includes, for example, time stamps, user/process identifiers, event descriptions, success/fail indications, filenames involved, and access control or flow control rules invoked. 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. The list of minimum DoD-defined audit events includes: -When privileges/permissions are retrieved, added, modified or deleted -When unsuccessful attempts to retrieve, add, modify, delete privileges/permissions occur -Enforcement of access restrictions associated with changes to the configuration of the database(s) -When security objects are accessed, modified, or deleted -When unsuccessful attempts to access, modify, or delete security objects occur -When categories of information (e.g., classification levels/security levels) are accessed, created, modified, or deleted -When unsuccessful attempts to access, create, modify, or delete categorized information occur -All privileged activities or other system-level access -When unsuccessful attempts to execute privileged activities or other system-level access occur -When successful or unsuccessful access to objects occur 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. Satisfies: SRG-APP-000095-DB-000039, SRG-APP-000091-DB-000325, SRG-APP-000096-DB-000040, SRG-APP-000097-DB-000041, SRG-APP-000098-DB-000042, SRG-APP-000099-DB-000043, SRG-APP-000100-DB-000201, SRG-APP-000381-DB-000361, SRG-APP-000492-DB-000332, SRG-APP-000492-DB-000333, SRG-APP-000494-DB-000344, SRG-APP-000494-DB-000345, SRG-APP-000495-DB-000326, SRG-APP-000495-DB-000327, SRG-APP-000495-DB-000328, SRG-APP-000495-DB-000329, SRG-APP-000496-DB-000334, SRG-APP-000496-DB-000335, SRG-APP-000498-DB-000346, SRG-APP-000498-DB-000347, SRG-APP-000499-DB-000330, SRG-APP-000499-DB-000331, SRG-APP-000501-DB-000336, SRG-APP-000501-DB-000337, SRG-APP-000502-DB-000348, SRG-APP-000502-DB-000349, SRG-APP-000504-DB-000354, SRG-APP-000504-DB-000355, SRG-APP-000507-DB-000356, SRG-APP-000507-DB-000357

Session auditing is used when a user's activities are under investigation. To ensure all activity is captured during those periods when session auditing is in use, it must be in operation for the entire time the DBMS is running.

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 group users, 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 group account users. In EnterpriseDB Postgres Plus Advanced Server, the edb_audit_tag can be used to record additional information. This tag can be set to different values by different sessions (connections), and can be set to new values any number of times. How to recognize the conditions for producing such audit data must be determined and coded for as part of application and database design.

It is critical that when the DBMS is at risk of failing to process audit logs as required, action be taken to mitigate the failure. Audit processing failures include: software/hardware errors; failures in the audit capturing mechanisms; and audit storage capacity being reached or exceeded. Responses to audit failure depend upon the nature of the failure mode. When the need for system availability does not outweigh the need for a complete audit trail, the DBMS should shut down immediately, rolling back all in-flight transactions. Systems where audit trail completeness is paramount will most likely be at a lower MAC level than MAC I; the final determination is the prerogative of the application owner, subject to Authorizing Official concurrence. In any case, sufficient auditing resources must be allocated to avoid a shutdown in all but the most extreme situations.

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.

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.

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 to 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.

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 to 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.

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 to 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.

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 to 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.

If the system were to allow any user to make changes to software libraries, then 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 will be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications. Monitoring is required for assurance that the protections are effective. 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 modules implemented within the database, then 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 will be allowed to obtain access to information system components for purposes of initiating changes, including upgrades and modifications. Monitoring is required for assurance that the protections are effective. Unmanaged changes that occur to the database software libraries or configuration can lead to unauthorized or compromised installations.

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.

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.

If the DBMS were to allow any user to make changes to database structure or logic, then 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.

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. Examples include, but are not limited to, installing advertising software, demonstrations, or browser plugins not related to requirements or providing a wide array of functionality, not required for every mission, that cannot be disabled. DBMSs must adhere to the principles of least functionality by providing only essential capabilities. Demonstration and sample database objects and applications present publicly known attack points for malicious users. These demonstration and sample objects are meant to provide simple examples of coding specific functions and are not developed to prevent vulnerabilities from being introduced to the DBMS and 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. DBMSs 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 software products to provide, or install by default, functionality exceeding requirements or mission objectives. DBMSs must adhere to the principles of least functionality by providing only essential capabilities. Unused, unnecessary DBMS components increase the attack vector for the DBMS 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.

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. EDB Postgres Advanced Server may spawn additional external processes to execute procedures that are defined in EDB Postgres Advanced Server 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 EDB Postgres Advanced Server and provide unauthorized access to the host system.

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. A Postgres database cluster (i.e., instance) listens for connections on a single TCP port. The default port for an EDB Postgres Advanced Server cluster is 5444; however, the port number that is used is configurable via the Postgres "port" parameter. A database restart is required to apply a change to the port parameter. Also by default, a Postgres cluster will listen for connections on all interfaces on the host. The "listen_addresses" parameter can be used to configure specific interfaces on the host to listen for connections. The default value of "*" indicates all interfaces are used. To listen only on specific interfaces, the listen_addresses parameter is configured with a comma-separated list of host names and/or numeric IP addresses corresponding to the interfaces that should be used. As with the port parameter, changes to the listen_addresses parameter requires a cluster restart to take effect.

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 in group accounts (e.g., shared privilege accounts) or for detailed accountability of individual activity.

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.

The EDB Postgres password file can contain passwords to be used if the connection allows a password (and no password has been specified otherwise). This file contain lines of the following format: hostname:port:database:username:password It is critically important to system security that use of a password file be avoided as it stores passwords in plain text. Any user with access to these could potentially compromise the security of the database.

Non-organizational users include all information system users other than organizational users, which include 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. With Postgres, all database users are uniquely identified. To discriminate non-organizational users from organizational users, applications often create and utilize one or more tables to record additional information about the users, including their organizational affiliations. Another approach that may be used is to create and assign database roles corresponding to the different organizations. The EDB Postgres Advanced Server session audit log tagging feature can also be used to log additional information about the user associated with a database session such as organizational affiliation. The session audit tagging feature uses the edb_audit_tag parameter. Typically, this parameter would be set on a session by session basis via the application that connects to the EDB Postgres Advanced Server database.

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 DBMS management is presented on an interface available for users, information on DBMS settings may inadvertently be made available to the user.

Failure to a known state can address safety or security in accordance with the mission/business needs of the organization. Failure to a known secure state helps prevent a loss of confidentiality, integrity, or availability in the event of a failure of the information system or a component of the system. Preserving information system state information helps to facilitate system restart and return to the operational mode of the organization with less disruption of mission/business processes. Since it is usually not possible to test this capability in a production environment, systems should either be validated in a testing environment or prior to installation. This requirement is usually a function of the design of the IDPS component. Compliance can be verified by acceptance/validation processes or vendor attestation. At all times, Postgres maintains a write ahead log (WAL) in the pg_wal/ subdirectory of the cluster's data directory. The log records every change made to the database's data files. This log exists primarily for crash-safety purposes: if the system crashes, the database can be restored to consistency by “replaying” the log entries made since the last checkpoint. Under the covers, Postgres uses fsync system calls to help ensure that modified database information held in memory is written to disk. To support certain specialized use cases where crash recovery is not as important as system performance, Postgres provides an fsync parameter that can be set to "off" to disable the use of fsync. By default, this parameter is set to "on" and except for the rare use cases should not be set to "off". To support being able to determine what may have caused a database failure, Postgres inherently logs failures.

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.

Applications, including DBMSs, 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 DBMSs, 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.

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 is 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, and REVOKE 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. 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.

Any DBMS 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 must 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. 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.

If EDB Postgres Advanced Server 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 EDB Postgres Advanced Server 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 appropriate approval. In addition to ensuring that access to EDB Postgres Advanced Server database and audit logs is restricted to authorized users and that EDB Postgres Advanced Server is configured to emit minimal information to clients related to Postgres generated errors, custom database code and external application code should also be designed to not emit detailed error messages to a client. 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.

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.

Without the association of security labels to information, there is no basis for EDB Postgres Advanced Server 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 a feature of EDB Postgres Advanced Server, a third-party product, or custom application code. In addition to being able to grant privileges on tables using standard SQL features, EDB Postgres Advanced Server provides a Row Level Security (RLS) feature. This feature provides the ability to define and enable row-level security policies that restrict insert, update, delete, and select access on the rows of a table on a per user basis. For deployments within the DoD, RLS policies are configured to use the assigned security labels.

Without the association of security labels to information, there is no basis for EDB Postgres Advanced Server 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 a feature of EDB Postgres Advanced Server, a third-party product, or custom application code. In addition to being able to grant privileges on tables using standard SQL features, EDB Postgres Advanced Server provides a Row Level Security (RLS) feature. This feature provides the ability to define and enable row level security policies that restrict insert, update, delete, and select access on the rows of a table on a per user basis. For deployments within the DoD, RLS policies are configured to use the assigned security labels.

Without the association of security labels to information, there is no basis for EDB Postgres Advanced Server 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 a feature of EDB Postgres Advanced Server, a third-party product, or custom application code. In addition to being able to grant privileges on tables using standard SQL features, EDB Postgres Advanced Server provides a Row Level Security (RLS) feature. This feature provides the ability to define and enable row level security policies that restrict insert, update, delete, and select access on the rows of a table on a per user basis. For deployments within the DoD, RLS policies are configured to use the assigned security labels.

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.

Preventing non-privileged users from executing privileged functions mitigates the risk that unauthorized individuals or processes may gain unnecessary access to information or privileges. System documentation should include a definition of the functionality considered privileged. Depending on circumstances, privileged functions can include, for example, establishing accounts, performing system integrity checks, or administering cryptographic key management activities. Non-privileged users are individuals that do not possess appropriate authorizations. Circumventing intrusion detection and prevention mechanisms or malicious code protection mechanisms are examples of privileged functions that require protection from non-privileged users. A privileged function in the DBMS/database 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 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 the DBMS and the design of the database and associated applications, the prevention of unauthorized use of privileged functions may be achieved by means of DBMS security features, database triggers, other mechanisms, or a combination of these. In Postgres, a user or group role that has been granted the SUPERUSER privilege can perform any action in the database. As such, the SUPERUSER privilege should only be granted to a limited set of approved users. The SUPERUSER privilege can be assigned to a role when the role is created. It can also be assigned or removed from a role via an ALTER ROLE statement. Postgres also provides the CREATEROLE, CREATEDB, REPLICATION, and BYPASSURLS privileges that can be granted to non-superuser roles to allow them to perform a limited set of privileged activities such as creating databases, creating user and group roles, managing replication slots, and bypassing row level security restrictions. Although not as all-encompassing as the SUPERUSER privilege, these privileges must only be granted to users who are approved to perform these activities. Like the SUPERUSER privilege, these privileges can be assigned to a role when the role is created. They can also be assigned or removed from a role via an ALTER ROLE statement. The PostgreSQL CREATE ROLE documentation provides more information about these privileges. See: https://www.postgresql.org/docs/current/sql-createrole.html In addition to the SUPERUSER, CREATEDB, and CREATEROLE privileges, a user may be granted one or more default roles that provide access to certain privileged capabilities and activities. A listing and description of the default roles provided with Postgres is documented at the following link: https://www.postgresql.org/docs/current/default-roles.html Roles and privileges on database objects can be granted to or revoked from a user using the GRANT and REVOKE statements. Users that are granted a role with the ADMIN OPTION can in turn grant the role to other users and roles. The ADMIN OPTION should only be granted to user and group roles that are approved to grant the roles. A description of the available privileges that may be granted to the different types of Postgres database objects is documented at the following link: https://www.postgresql.org/docs/current/ddl-priv.html Also in Postgres, for most object types, object owners can perform any action on the objects they own, including dropping or altering them and assigning or revoking privileges on them. As such, database objects should only be owned by users who are approved to own them. Another security risk to consider, is that Postgres can be extended with additional procedural languages that can be used to create user defined functions (i.e., not provided by EDB Postgres Advanced Server out-of-the-box). Some of these languages, such as pl/Python and pl/R are defined as "untrusted" languages. Any users who are granted access to these untrusted languages are able to run user defined functions to escalate privileges and perform unintended functions. These languages allow a Postgres database to be extended with additional capabilities that may be of benefit to a system. However, usage of these languages should only be granted to approved users for documented and approved purposes.

In certain situations, to provide required functionality, a DBMS must 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.

In certain situations, to provide required functionality, a DBMS must 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.

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. The DBMS 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.

If the configuration of the DBMS's auditing is spread across multiple locations in the database management software, or across multiple commands, only loosely related, it is harder to use and takes longer to reconfigure in response to events. The DBMS must provide a unified tool for audit configuration.

To ensure sufficient storage capacity for the audit logs, the DBMS 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 the DBMS 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 the DBMS's ability to reuse the space formerly occupied by off-loaded records.

Organizations are required to use a central log management system, so, under normal conditions, the audit space allocated to EDB Postgres on its own server will not be an issue. However, space will still be required on the EDB Postgres 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.

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 EDB Postgres, the OS, third-party software, custom code, or a combination of these. The term "the system" is used to encompass all of these.

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. DBMS 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. The DBMS 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.

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 must be allowed to obtain access to system components for the purposes of initiating changes, including upgrades and modifications.

Use of nonsecure network functions, ports, protocols, and services exposes the system to avoidable threats. A database cluster listens on a single port (usually 5444 for Postgres Plus Advanced Server). The Postgres Enterprise Manager (PEM) agents do not listen on ports, they only act as clients to the PEM server. The PEM server has two components (a repository which is a Postgres database) and an Apache HTTPD application. The Apache HTTPD application listens on a port configured in Apache, generally 8080 or 8443. The ports to check are: 1) The primary Postgres cluster port, 2) If PEM is in use, the PEM Apache HTTPD port, and 3) The PEM Repository DB port. Generally 2 and 3 should be installed on an isolated management machine without access from anyone other than administrators.

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 re-authentication is required. Without re-authentication, 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 re-authentication requirements associated with session locks, organizations may require re-authentication 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 categories of 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 re-authentication are privilege escalation and role changes.

Only DoD-approved external PKIs evaluated to ensure security controls and identity vetting procedures are in place that 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 https://cyber.mil/pki-pke/interoperability/. This requirement focuses on communications protection for the DBMS session rather than for the network packet.

DBMSs 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 the DBMS 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.

DBMSs 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 the DBMS 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 influenced by the physical measures taken to secure the equipment and media on which the information resides.

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, the DBMS, associated applications, and infrastructure must leverage transmission protection mechanisms. EDB Postgres Advanced Server provides native support for using SSL connections to encrypt client/server communications. To enable the use of SSL, the postgres “ssl” configuration parameter must be set to “on” and the database instance needs to be configured to use a valid server certificate and private key installed on the server. With SSL enabled, connections made to the database server will default to being encrypted. However, it is possible for clients to override the default and attempt to establish an unencrypted connection. To prevent connections made from non-local hosts from being unencrypted, the postgres host-based authentication settings should be configured to only allow hostssl (i.e., encrypted) connections. The hostssl connections can be further configured to require the client present a valid (trusted) SSL certificate for a connection.

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 non-locally. 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, the DBMS, associated applications, and infrastructure must leverage protection mechanisms. EDB Postgres Advanced Server provides native support for using SSL connections to encrypt client/server communications. To enable the use of SSL, the postgres “ssl” configuration parameter must be set to “on” and the database instance needs to be configured to use a valid server certificate and private key installed on the server. With SSL enabled, connections made to the database server will default to being encrypted. However, it is possible for clients to override the default and attempt to establish an unencrypted connection. To prevent connections made from non-local hosts from being unencrypted, the postgres host-based authentication settings should be configured to only allow hostssl (i.e., encrypted) connections. The hostssl connections can be further configured to require the client present a valid (trusted) SSL certificate for a connection.

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. 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.

Security flaws with software applications, including database management systems, are discovered daily. Vendors are constantly updating and patching their products to address newly discovered security vulnerabilities. Organizations (including any contractor to the organization) are required to promptly install security-relevant software updates (e.g., patches, service packs, and hot fixes). Flaws discovered during security assessments, continuous monitoring, incident response activities, or information system error handling must also be addressed expeditiously. Organization-defined time periods for updating security-relevant software may vary based on a variety of factors including, for example, the security category of the information system or the criticality of the update (i.e., severity of the vulnerability related to the discovered flaw). This requirement will apply to software patch management solutions that are used to install patches across the enclave and also to applications themselves that are not part of that patch management solution. For example, many browsers today provide the capability to install their own patch software. Patch criticality, as well as system criticality, will vary. Therefore, the tactical situations regarding the patch management process will also vary. This means the time period utilized must be a configurable parameter. Timeframes for application of security-relevant software updates may be dependent upon the Information Assurance Vulnerability Management (IAVM) process. The application will be configured to check for and install security-relevant software updates within an identified time period from the availability of the update. The specific time period will be defined by an authoritative source (e.g., IAVM, CTOs, DTMs, and STIGs).

For completeness of forensic analysis, it is necessary to track who/what (a user or other principal) logs on to the DBMS. It is also necessary to track failed attempts to log on to the DBMS. While positive identification may not be possible in a case of failed authentication, as much information as possible about the incident must be captured. Satisfies: SRG-APP-000503-DB-000350,SRG-APP-000503-DB-000351

For completeness of forensic analysis, it is necessary to know how long a user's (or other principal's) connection to the DBMS 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. 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.) Satisfies: SRG-APP-000505-DB-000352,SRG-APP-000506-DB-000353

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.

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 of testing and validation. For detailed information, refer to NIST FIPS Publication 140-3, Security Requirements For Cryptographic Modules. Note that the product's cryptographic modules must be validated and certified by NIST as FIPS-compliant.

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. The DBMS may write audit records to database tables, to files in the file system, to other kinds of local repositories, 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.

Configuring the DBMS to implement organization-wide security implementation guides and security checklists ensures compliance with federal standards and establishes a common security baseline across DoD that reflects the most restrictive security posture consistent with operational requirements. In addition to this SRG, sources of guidance on security and information assurance exist. These include NSA configuration guides, CTOs, DTMs, and IAVMs. The DBMS must be configured in compliance with guidance from all such relevant sources.