AAA Services Security Requirements Guide

Enterprise environments make account management challenging and complex. A manual process for account management functions adds the risk of a potential oversight or other error. A comprehensive account management process that includes automation helps to ensure accounts designated as requiring attention are consistently and promptly addressed. Examples include, but are not limited to, using automation to disable inactive accounts after a specified time period, or to lock accounts after a specified number of unsuccessful attempts at logon. AAA Services must be configured to automatically provide account management functions, and these functions must immediately enforce the organization's current account policy. The automated mechanisms may reside within AAA Services or may be directory services providing automated account management externally. Automated mechanisms may be composed of differing technologies that when placed together contain an overall automated mechanism supporting an organization's automated account management requirements. Account management functions include assignment of 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 automatically notifying account managers when users are terminated or transferred; using the information system to monitor account usage; and using automated telephonic notification to report atypical system account usage.

When temporary user accounts remain active after no longer needed or for an excessive period, these accounts may be used to gain unauthorized access. To mitigate this risk, automated termination of all temporary user accounts must be set upon account creation. Disabling a temporary account provides a higher risk alternative; disabling allows an insider adversary to enable the privileged account and make it permanent. Temporary accounts, when used, mandate that AAA Services must be configured to automatically terminate these types of accounts after 72 hours. When AAA Services do not perform account management, the connected Active Directory must provide this setting.

When temporary user accounts remain active after no longer needed or for an excessive period, these accounts may be used to gain unauthorized access. To mitigate this risk, automated termination of all temporary user accounts must be set upon account creation. Disabling a temporary account provides a higher risk alternative; disabling allows an insider adversary to enable the privileged account and make it permanent. Temporary accounts, when used, mandate that AAA Services must be configured to automatically terminate these types of accounts after 72 hours. When AAA Services do not perform account management, the connected Active Directory must provide this setting.

Attackers that are able to exploit an inactive account can potentially obtain and maintain undetected access to an application. Owners of inactive accounts will not notice if unauthorized access to their user account has been obtained. Applications need to track periods of user inactivity and disable accounts after 35 days of inactivity. Such a process greatly reduces the risk that accounts will be hijacked, leading to a data compromise. This policy does not apply to either emergency accounts or an infrequently used account (e.g., account of last resort). Infrequently used accounts are local logon administrator accounts used by system administrators when network or normal logon/access is not available. Emergency accounts are administrator accounts created in response to crisis situations.

Once an attacker establishes access to a system, the attacker often attempts to create a persistent method of reestablishing access. One way to accomplish this is for the attacker to simply create a new account. Auditing of account creation is one method for mitigating this risk. A comprehensive account management process will ensure an audit trail documents the creation of user accounts and, as required, notifies administrators and/or managers. Such a process greatly reduces the risk that accounts will be surreptitiously created and provides logging that can be used for forensic purposes.

Once an attacker establishes access to a system, the attacker often attempts to create a persistent method of reestablishing access. One way to accomplish this is for the attacker to simply modify an existing account. Auditing of account modification is one method for mitigating this risk. A comprehensive account management process will ensure an audit trail documents the modification of user accounts and, as required, notifies administrators and/or managers. Such a process greatly reduces the risk that accounts will be surreptitiously modified and provides logging that can be used for forensic purposes.

When application accounts are disabled, user accessibility is affected. Once an attacker establishes access to an application, the attacker often attempts to disable authorized accounts to disrupt services or prevent the implementation of countermeasures. Auditing account disabling actions provides logging that can be used for forensic purposes.

When application accounts are removed, user accessibility is affected. Once an attacker establishes access to an application, the attacker often attempts to remove authorized accounts to disrupt services or prevent the implementation of countermeasures. Auditing account removal actions provides logging that can be used for forensic purposes.

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute forcing, is reduced. Limits are imposed by locking the 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 application (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 application 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.

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, source and destination addresses, 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.

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 when events occurred (date and time). 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.

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.

Without establishing the source of the event, it is impossible to establish, correlate, and investigate the events leading up to an outage or attack. 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. In the case of centralized logging, the source would be the application name accompanied by the host or client name. In order to compile an accurate risk assessment, and provide forensic analysis, it is essential for security personnel to know the source of the event, particularly in the case of centralized logging. 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.

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.

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. Event identifiers (if authenticated or otherwise known) include, but are not limited to, user database tables, primary key values, user names, or process identifiers.

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 this notification, the security personnel may be unaware of an impending failure of the audit capability and system operation may be adversely affected. Audit processing failures include software/hardware errors, failures in the audit capturing mechanisms, and audit storage capacity being reached or exceeded. This requirement applies to each audit data storage repository (i.e., distinct information system component where audit records are stored), the centralized audit storage capacity of organizations (i.e., all audit data storage repositories combined), or both.

It is critical that when AAA Services are at risk of failing to process audit logs as required, they take action 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. For AAA Services, availability is an overriding concern, and so both of the following approved actions in response to an audit failure must be met: (i) If the failure was caused by the lack of audit record storage capacity, AAA Services must continue generating audit records if possible (automatically restarting the audit service if necessary), overwriting the oldest audit records in a first-in-first-out manner. (ii) If audit records are sent to a centralized collection server and communication with this server is lost or the server fails, AAA Services must queue audit records locally until communication is restored or until the audit records are retrieved manually. Upon restoration of the connection to the centralized collection server, action should be taken to synchronize the local audit data with the collection server.

It is critical that when AAA Services are at risk of failing to process audit logs as required, it take action 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. For AAA Services, availability is an overriding concern, and so both of the following approved actions in response to an audit failure must be met: (i) If the failure was caused by the lack of audit record storage capacity, AAA Services must continue generating audit records if possible (automatically restarting the audit service if necessary), overwriting the oldest audit records in a first-in-first-out manner. (ii) If audit records are sent to a centralized collection server and communication with this server is lost or the server fails, AAA Services must queue audit records locally until communication is restored or until the audit records are retrieved manually. Upon restoration of the connection to the centralized collection server, action should be taken to synchronize the local audit data with the collection server.

Without an internal clock used as the reference for the time stored on each event to provide a trusted common reference for the time, forensic analysis would be impeded. Determining the correct time a particular event occurred on a system is critical when conducting forensic analysis and investigating system events. If the internal clock is not used, the system may not be able to provide time stamps for log messages. Additionally, externally generated time stamps may not be accurate. Applications can use the capability of an operating system or purpose-built module for this purpose. Synchronizing the internal clock using NTP provides uniformity for all system clocks over a network. NTP provides an efficient and scalable method for network devices to synchronize to an accurate time source.

It is detrimental for applications to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. 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 (e.g., key missions, functions). Examples of non-essential capabilities include, but are not limited to, advertising software or browser plug-ins not related to requirements or providing a wide array of functionality not required for every mission, but cannot be disabled.

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 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.

Without the use of multifactor authentication, the ease of access to privileged functions is greatly increased. Multifactor authentication requires using two or more factors to achieve authentication. Factors include: (i) something a user knows (e.g., password/PIN); (ii) something a user has (e.g., cryptographic identification device, token); or (iii) something a user is (e.g., biometric). A privileged account is defined as an information system account with authorizations of a privileged user. Network access is defined as access to an information system by a user (or a process acting on behalf of a user) communicating through a network (e.g., local area network, wide area network, or the Internet).

To assure accountability and prevent unauthenticated access, non-privileged users must utilize multifactor authentication to prevent potential misuse and compromise of the system. Multifactor authentication uses two or more factors to achieve authentication. Factors include: (i) Something you know (e.g., password/PIN); (ii) Something you have (e.g., cryptographic identification device, token); or (iii) Something you are (e.g., biometric). A non-privileged account is any information system account with authorizations of a non-privileged user. Network access is any access to an application by a user (or process acting on behalf of a user) where said access is obtained through a network connection. Applications integrating with the DoD Active Directory and using the DoD CAC are examples of compliant multifactor authentication solutions.

Without identifying devices, unidentified or unknown devices may be introduced, thereby facilitating malicious activity. For distributed architectures (e.g., service-oriented architectures), the decisions regarding the validation of identification claims may be made by services separate from the services acting on those decisions. In such situations, it is necessary to provide the identification decisions (as opposed to the actual identifiers) to the services that need to act on those decisions. This requirement applies to applications that connect either locally, remotely, or through a network to an endpoint device (including but not limited to workstations, printers, servers [outside a datacenter], VoIP phones, VTC CODECs). Gateways and SOA applications are examples of where this requirement would apply.

Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password length is one factor of several that helps to determine strength and how long it takes to crack a password. The shorter the password, the lower the number of possible combinations that need to be tested before the password is compromised. Use of more characters in a password helps to exponentially increase the time and/or resources required to compromise the password.

Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Use of a complex password helps to increase the time and resources required to compromise the password. The more complex the password is, the greater the number of possible combinations that need to be tested before the password is compromised.

Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Use of a complex password helps to increase the time and resources required to compromise the password. The more complex the password is, the greater the number of possible combinations that need to be tested before the password is compromised.

Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Use of a complex password helps to increase the time and resources required to compromise the password. The more complex the password is, the greater the number of possible combinations that need to be tested before the password is compromised.

Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Use of a complex password helps to increase the time and resources required to compromise the password. The more complex the password is, the greater the number of possible combinations that need to be tested before the password is compromised. Special characters are those characters that are not alphanumeric. Examples include: ~ ! @ # $ % ^ *.

Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Use of a complex password helps to increase the time and resources required to compromise the password. The more complex the password is, the greater the number of possible combinations that need to be tested before the password is compromised.

Enforcing a minimum password lifetime helps prevent repeated password changes to defeat the password reuse or history enforcement requirement. Restricting this setting limits the user's ability to change their password. Passwords need to be changed at specific policy based intervals; however, if the application allows the user to immediately and continually change their password, then the password could be repeatedly changed in a short period of time to defeat the organization's policy regarding password reuse.

Any password, no matter how complex, can eventually be cracked; therefore, passwords must be changed at specific intervals. One method of minimizing this risk is to use complex passwords and periodically change them. If the application does not limit the lifetime of passwords and force users to change their passwords, there is the risk that the system and/or application passwords could be compromised. This requirement does not include emergency administration accounts that are meant for access to the application in case of failure. These accounts are not required to have maximum password lifetime restrictions.

If the private key is discovered, an attacker can use the key to authenticate as an authorized user and gain access to the network infrastructure. The cornerstone of the PKI is the private key used to encrypt or digitally sign information. If the private key is stolen, this will lead to the compromise of the authentication and non-repudiation gained through PKI because the attacker can use the private key to digitally sign documents and pretend to be the authorized user. Both the holders of a digital certificate and the issuing authority must protect the computers, storage devices, or whatever they use to keep the private keys.

Without mapping the certificate used to authenticate to the user account, the ability to determine the identity of the individual user or group will not be available for forensic analysis.

Emergency accounts are administrator accounts that are established in response to crisis situations where the need for rapid account activation is required. Therefore, emergency account activation may bypass normal account authorization processes. If these accounts are automatically disabled, system maintenance during emergencies may not be possible, thus adversely affecting system availability. Emergency accounts are different from infrequently used accounts (i.e., local logon accounts used by system administrators when network or normal logon/access is not available). Infrequently used accounts also remain available and are not subject to automatic termination dates. However, an emergency account is normally a different account that is created for use by vendors or system maintainers, that is removed once the crisis has passed. When AAA Services do not perform account management, the connected Active Directory must provide this setting

Once an attacker establishes access to an application, the attacker often attempts to create a persistent method of re-establishing access. One way to accomplish this is for the attacker to simply create a new account. Sending notification of account creation events to the system administrator and ISSO is one method for mitigating this risk. AAA Services may not have built-in capabilities to notify the administrators and ISSO and may require the use of third-party tools (e.g. SNMP, SIEM) to perform the notification.

When application accounts are modified, user accessibility is affected. Accounts are utilized for identifying individual users or for identifying the application processes themselves. Sending notification of account modification events to the SA and ISSO is one method for mitigating this risk. Such a capability greatly reduces the risk that application accessibility will be negatively affected for extended periods of time and provides logging that can be used for forensic purposes. AAA Services may not have built-in capabilities to notify the administrators and ISSO and may require the use of third-party tools (e.g., SNMP, SIEM) to perform the notification.

When application accounts are disabled, user accessibility is affected. Accounts are utilized for identifying individual users or for identifying the application processes themselves. Sending notification of account disabling events to the SA and ISSO is one method for mitigating this risk. Such a capability greatly reduces the risk that application accessibility will be negatively affected for extended periods of time and provides logging that can be used for forensic purposes. AAA Services may not have built-in capabilities to notify the administrators and ISSO and may require the use of third-party tools (e.g., SNMP, SIEM) to perform the notification.

When application accounts are removed, user accessibility is affected. Accounts are utilized for identifying users or for identifying the application processes themselves. Sending notification of account removal events to the system administrator and ISSO is one method for mitigating this risk. Such a capability greatly reduces the risk that application accessibility will be negatively affected for extended periods of time and provides logging that can be used for forensic purposes. AAA Services may not have built-in capabilities to notify system administrators and ISSO and may require the use of third-party tools (e.g. SNMP, SIEM) to perform the notification.

Once an attacker establishes access to an application, the attacker often attempts to create a persistent method of reestablishing access. One way to accomplish this is for the attacker to simply enable a new or disabled account. Automatically auditing account enabling actions provides logging that can be used for forensic purposes.

Once an attacker establishes access to an application, the attacker often attempts to create a persistent method of reestablishing access. One way to accomplish this is for the attacker to simply enable a new or disabled account. Sending notification of account enabling events to the system administrator and ISSO is one method for mitigating this risk. Such a capability greatly reduces the risk that application accessibility will be negatively affected for extended periods of time and provides logging that can be used for forensic purposes. In order to detect and respond to events that affect user accessibility and application processing, the AAA or directory services must notify the appropriate individuals so they can investigate the event. AAA Services may not have built-in capabilities to notify the administrators and ISSO and may require the use of third-party tools (e.g. SNMP, SIEM) to perform the notification.

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute forcing, is reduced. Limits are imposed by locking the account.

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.

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 the application include date and time. Time is commonly expressed in Coordinated Universal Time (UTC) or local time with an offset from UTC.

Without sufficient granularity of time stamps, it is not possible to adequately determine the chronological order of records. Time stamps generated by the application include date and time. Granularity of time measurements refers to the degree of synchronization between information system clocks and reference clocks.

Without authenticating devices, unidentified or unknown devices may be introduced, thereby facilitating malicious activity. For distributed architectures (e.g., service-oriented architectures), the decisions regarding the validation of authentication claims may be made by services separate from the services acting on those decisions. In such situations, it is necessary to provide authentication decisions (as opposed to the actual authenticators) to the services that need to act on those decisions. This requirement applies to applications that connect either locally, remotely, or through a network to an endpoint device (including but not limited to workstations, printers, servers [outside a datacenter], VoIP phones, VTC CODECs). Gateways and SOA applications are examples of where this requirement would apply. Device authentication is a solution enabling an organization to manage devices. It is an additional layer of authentication ensuring only specific pre-authorized devices can access the system.

Inaccurate time stamps make it more difficult to correlate events and can lead to an inaccurate analysis. Determining the correct time a particular event occurred on a system is critical when conducting forensic analysis and investigating system events. Sources outside of the configured acceptable allowance (drift) may be inaccurate. Additionally, unnecessary synchronization may have an adverse impact on system performance and may indicate malicious activity. Synchronizing internal information system clocks provides uniformity of time stamps for information systems with multiple system clocks and systems connected over a network. NTP provides an efficient and scalable method for network devices to synchronize to an accurate time source. NTP may pose a security risk if a malicious user were able to falsify NTP information. To launch an attack on the NTP infrastructure, a hacker could inject time that would be accepted by NTP clients by spoofing the IP address of a valid NTP server. To mitigate this risk, the time messages must be authenticated by the client before accepting them as a time source. Two NTP-enabled devices can communicate in either client-server mode or peer-to-peer mode (aka "symmetric mode"). The peering mode is configured manually on the device and indicated in the outgoing NTP packets. The fundamental difference is the synchronization behavior: an NTP server can synchronize to a peer with better stratum, whereas it will never synchronize to its client regardless of the client's stratum. From a protocol perspective, NTP clients are no different from the NTP servers. The NTP client can synchronize to multiple NTP servers, select the best server and synchronize with it, or synchronize to the averaged value returned by the servers. A hierarchical model can be used to improve scalability. With this implementation, an NTP client can also become an NTP server providing time to downstream clients at a higher stratum level and of decreasing accuracy than that of its upstream server. To increase availability, NTP peering can be used between NTP servers. In the event the device loses connectivity to its upstream NTP server, it will be able to choose time from one of its peers. The NTP authentication model is opposite of the typical client-server authentication model. NTP authentication enables an NTP client or peer to authenticate time received from their servers and peers. It is not used to authenticate NTP clients because NTP servers do not care about the authenticity of their clients, as they never accept any time from them.

Additional new EAP methods/types are still being proposed. However, the three being considered secure are EAP-TLS, EAP-TTLS, and PEAP. PEAP is the preferred EAP type to be used in DoD for its ability to support a greater number of operating systems and its capability to transmit statement of health information, per NSA NAC study. Lightweight EAP (LEAP) is a CISCO proprietary protocol providing an easy-to-deploy one-password authentication. LEAP is vulnerable to dictionary attacks. A "man in the middle" can capture traffic, identify a password, and then use it to access a WLAN. LEAP is inappropriate and does not provide sufficient security for use on DOD networks. EAP-MD5 is functionally similar to CHAP and is susceptible to eavesdropping because the password credentials are sent as a hash (not encrypted). In addition, server administrators would be required to store unencrypted passwords on their servers violating other security policies. EAP-MD5 is inappropriate and does not provide sufficient security for use on DOD networks.

Shared accounts configured for use on a network device do not allow for accountability or repudiation of individuals using them. If shared accounts are not changed when someone leaves the group, that person could possibly gain control of the network device. Having shared accounts does not allow for proper auditing of who is accessing or changing the network. For this reason, shared accounts are not permitted.

Using standardized authentication protocols such as RADIUS, TACACS+, and Kerberos, an authentication server provides centralized and robust authentication services for the management of network components. In order to control access to the servers as well as monitor traffic to them, the authentication servers should only be connected to the management network.

Using standardized authentication protocols such as RADIUS, TACACS+, and Kerberos, an authentication server provides centralized and robust authentication services for the management of network components. An authentication server is very scalable as it supports many user accounts and authentication sessions with the network components.

When policy assessment and remediation have been implemented and the advanced AAA server dynamic VLAN is misconfigured, logical separation of the production VLAN may not be assured. Non-trusted resources are resources that are not authenticated in a NAC solution implementing only the authentication component of NAC. Non-trusted resources could become resources that have been authenticated but have not had a successful policy assessment when the automated policy assessment component has been implemented.

Devices having an IP address that do not pass authentication can be used to attack compliant devices if they share VLANs. When devices proceed into the NAC AAA (radius) functions they must originate in the Unauthorized VLAN by default. If the device fails authentication, it should be denied IP capability and movement to other dynamic VLANs used in the NAC process flow or moved to a VLAN that has limited capability such as a Guest VLAN with internet access, but without access to production assets.

Configuring the application 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. Configuration settings are the set of parameters that can be changed that affect the security posture and/or functionality of the system. Security-related parameters are those parameters impacting the security state of the application, including the parameters required to satisfy other security control requirements.

Disabling expired, inactive, or otherwise anomalous accounts supports the concepts of least privilege and least functionality, which reduce the attack surface of the system.

Disabling expired, inactive, or otherwise anomalous accounts supports the concepts of least privilege and least functionality, which reduce the attack surface of the system.

Disabling expired, inactive, or otherwise anomalous accounts supports the concepts of least privilege and least functionality, which reduce the attack surface of the system.

Organizations log system accesses associated with applying configuration changes to ensure that configuration change control is implemented and to support after-the-fact actions should organizations discover any unauthorized changes.

Individual authentication prior to shared group authentication mitigates the risk of using group accounts or authenticators.

Password-based authentication applies to passwords regardless of whether they are used in single-factor or multi-factor authentication. Long passwords or passphrases are preferable over shorter passwords. Enforced composition rules provide marginal security benefits while decreasing usability. However, organizations may choose to establish certain rules for password generation (e.g., minimum character length for long passwords) under certain circumstances and can enforce this requirement in IA-5(1)(h). Account recovery can occur, for example, in situations when a password is forgotten. Cryptographically protected passwords include salted one-way cryptographic hashes of passwords. The list of commonly used, compromised, or expected passwords includes passwords obtained from previous breach corpuses, dictionary words, and repetitive or sequential characters. The list includes context-specific words, such as the name of the service, username, and derivatives thereof.

Password-based authentication applies to passwords regardless of whether they are used in single-factor or multi-factor authentication. Long passwords or passphrases are preferable over shorter passwords. Enforced composition rules provide marginal security benefits while decreasing usability. However, organizations may choose to establish certain rules for password generation (e.g., minimum character length for long passwords) under certain circumstances and can enforce this requirement in IA-5(1)(h). Account recovery can occur, for example, in situations when a password is forgotten. Cryptographically protected passwords include salted one-way cryptographic hashes of passwords. The list of commonly used, compromised, or expected passwords includes passwords obtained from previous breach corpuses, dictionary words, and repetitive or sequential characters. The list includes context-specific words, such as the name of the service, username, and derivatives thereof.

Password-based authentication applies to passwords regardless of whether they are used in single-factor or multi-factor authentication. Long passwords or passphrases are preferable over shorter passwords. Enforced composition rules provide marginal security benefits while decreasing usability. However, organizations may choose to establish certain rules for password generation (e.g., minimum character length for long passwords) under certain circumstances and can enforce this requirement in IA-5(1)(h). Account recovery can occur, for example, in situations when a password is forgotten. Cryptographically protected passwords include salted one-way cryptographic hashes of passwords. The list of commonly used, compromised, or expected passwords includes passwords obtained from previous breach corpuses, dictionary words, and repetitive or sequential characters. The list includes context-specific words, such as the name of the service, username, and derivatives thereof.

Password-based authentication applies to passwords regardless of whether they are used in single-factor or multi-factor authentication. Long passwords or passphrases are preferable over shorter passwords. Enforced composition rules provide marginal security benefits while decreasing usability. However, organizations may choose to establish certain rules for password generation (e.g., minimum character length for long passwords) under certain circumstances and can enforce this requirement in IA-5(1)(h). Account recovery can occur, for example, in situations when a password is forgotten. Cryptographically protected passwords include salted one-way cryptographic hashes of passwords. The list of commonly used, compromised, or expected passwords includes passwords obtained from previous breach corpuses, dictionary words, and repetitive or sequential characters. The list includes context-specific words, such as the name of the service, username, and derivatives thereof.

Password-based authentication applies to passwords regardless of whether they are used in single-factor or multi-factor authentication. Long passwords or passphrases are preferable over shorter passwords. Enforced composition rules provide marginal security benefits while decreasing usability. However, organizations may choose to establish certain rules for password generation (e.g., minimum character length for long passwords) under certain circumstances and can enforce this requirement in IA-5(1)(h). Account recovery can occur, for example, in situations when a password is forgotten. Cryptographically protected passwords include salted one-way cryptographic hashes of passwords. The list of commonly used, compromised, or expected passwords includes passwords obtained from previous breach corpuses, dictionary words, and repetitive or sequential characters. The list includes context-specific words, such as the name of the service, username, and derivatives thereof.

Password-based authentication applies to passwords regardless of whether they are used in single-factor or multi-factor authentication. Long passwords or passphrases are preferable over shorter passwords. Enforced composition rules provide marginal security benefits while decreasing usability. However, organizations may choose to establish certain rules for password generation (e.g., minimum character length for long passwords) under certain circumstances and can enforce this requirement in IA-5(1)(h). Account recovery can occur, for example, in situations when a password is forgotten. Cryptographically protected passwords include salted one-way cryptographic hashes of passwords. The list of commonly used, compromised, or expected passwords includes passwords obtained from previous breach corpuses, dictionary words, and repetitive or sequential characters. The list includes context-specific words, such as the name of the service, username, and derivatives thereof.

Public key cryptography is a valid authentication mechanism for individuals, machines, and devices. For PKI solutions, status information for certification paths includes certificate revocation lists or certificate status protocol responses. For PIV cards, certificate validation involves the construction and verification of a certification path to the Common Policy Root trust anchor, which includes certificate policy processing. Implementing a local cache of revocation data to support path discovery and validation also supports system availability in situations where organizations are unable to access revocation information via the network.

Public key infrastructure (PKI) certificates are certificates with visibility external to organizational systems and certificates related to the internal operations of systems, such as application-specific time services. In cryptographic systems with a hierarchical structure, a trust anchor is an authoritative source (i.e., a certificate authority) for which trust is assumed and not derived. A root certificate for a PKI system is an example of a trust anchor. A trust store or certificate store maintains a list of trusted root certificates.