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XCCDF
Cisco IOS Router NDM Security Technical Implementation Guide
Cisco IOS Router NDM Security Technical Implementation Guide
An XCCDF Benchmark
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43 rules organized in 43 groups
SRG-APP-000001-NDM-000200
1 Rule
The Cisco router must be configured to limit the number of concurrent management sessions to an organization-defined number.
Medium Severity
Device management includes the ability to control the number of administrators and management sessions that manage a device. Limiting the number of allowed administrators and sessions per administrator based on account type, role, or access type is helpful in limiting risks related to DoS attacks. This requirement addresses concurrent sessions for administrative accounts and does not address concurrent sessions by a single administrator via multiple administrative accounts. The maximum number of concurrent sessions should be defined based upon mission needs and the operational environment for each system. At a minimum, limits must be set for SSH, HTTPS, account of last resort, and root account sessions.
SRG-APP-000026-NDM-000208
1 Rule
The Cisco router must be configured to automatically audit account creation.
Medium Severity
Upon gaining access to a network device, an attacker will often first attempt to create a persistent method of reestablishing access. One way to accomplish this is to create a new account. Notification of account creation helps to mitigate this risk. Auditing account creation provides the necessary reconciliation that account management procedures are being followed. Without this audit trail, personnel without the proper authorization may gain access to critical network nodes.
SRG-APP-000027-NDM-000209
1 Rule
The Cisco router must be configured to automatically audit account modification.
Medium Severity
Since the accounts in the network device are privileged or system-level accounts, account management is vital to the security of the network device. Account management by a designated authority ensures access to the network device is being controlled in a secure manner by granting access to only authorized personnel with the appropriate and necessary privileges. Auditing account modification along with an automatic notification to appropriate individuals will provide the necessary reconciliation that account management procedures are being followed. If modifications to management accounts are not audited, reconciliation of account management procedures cannot be tracked.
SRG-APP-000028-NDM-000210
1 Rule
The Cisco router must be configured to automatically audit account disabling actions.
Medium Severity
Account management, as a whole, ensures access to the network device is being controlled in a secure manner by granting access to only authorized personnel. Auditing account disabling actions will support account management procedures. When device management accounts are disabled, user or service accessibility may be affected. Auditing also ensures authorized active accounts remain enabled and available for use when required.
SRG-APP-000029-NDM-000211
1 Rule
The Cisco router must be configured to automatically audit account removal actions.
Medium Severity
Account management, as a whole, ensures access to the network device is being controlled in a secure manner by granting access to only authorized personnel. Auditing account removal actions will support account management procedures. When device management accounts are terminated, user or service accessibility may be affected. Auditing also ensures authorized active accounts remain enabled and available for use when required.
SRG-APP-000038-NDM-000213
1 Rule
The Cisco router must be configured to enforce approved authorizations for controlling the flow of management information within the device based on control policies.
Medium Severity
A mechanism to detect and prevent unauthorized communication flow must be configured or provided as part of the system design. If management information flow is not enforced based on approved authorizations, the network device may become compromised. Information flow control regulates where management information is allowed to travel within a network device. The flow of all management information must be monitored and controlled so it does not introduce any unacceptable risk to the network device or data. Application-specific examples of enforcement occur in systems that employ rule sets or establish configuration settings that restrict information system services or message-filtering capability based on message content (e.g., implementing key word searches or using document characteristics). Applications providing information flow control must be able to enforce approved authorizations for controlling the flow of management information within the system in accordance with applicable policy.
SRG-APP-000065-NDM-000214
1 Rule
The Cisco router must be configured to enforce the limit of three consecutive invalid logon attempts, after which time it must lock out the user account from accessing the device for 15 minutes.
Medium Severity
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.
SRG-APP-000068-NDM-000215
1 Rule
The Cisco router must be configured to display the Standard Mandatory DoD Notice and Consent Banner before granting access to the device.
Medium Severity
Display of the DoD-approved use notification before granting access to the network device ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance. System use notifications are required only for access via logon interfaces with human users.
SRG-APP-000080-NDM-000345
1 Rule
The Cisco device must be configured to audit all administrator activity.
Medium Severity
This requirement supports non-repudiation of actions taken by an administrator and is required in order to maintain the integrity of the configuration management process. All configuration changes to the network device are logged, and administrators authenticate with two-factor authentication before gaining administrative access. Together, these processes will ensure the administrators can be held accountable for the configuration changes they implement. To meet this requirement, the network device must log administrator access and activity.
SRG-APP-000096-NDM-000226
1 Rule
The Cisco router must produce audit records containing information to establish when (date and time) the events occurred.
Medium Severity
It is essential for security personnel to know what is being done, what was attempted, where it was done, when it was done, and by whom it was done in order to compile an accurate risk assessment. Logging the date and time of each detected event provides a means of investigating an attack; recognizing resource utilization or capacity thresholds; or identifying an improperly configured network device. In order to establish and correlate the series of events leading up to an outage or attack, it is imperative the date and time are recorded in all log records.
SRG-APP-000097-NDM-000227
1 Rule
The Cisco router must produce audit records containing information to establish where the events occurred.
Medium Severity
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 device hardware components, device software modules, session identifiers, filenames, host names, and functionality. Associating information about where the event occurred within the network device provides a means of investigating an attack; recognizing resource utilization or capacity thresholds; or identifying an improperly configured device.
SRG-APP-000101-NDM-000231
1 Rule
The Cisco router must be configured to generate audit records containing the full-text recording of privileged commands.
Medium Severity
Reconstruction of harmful events or forensic analysis is not possible if audit records do not contain enough information. Organizations consider limiting the additional audit information to only that information explicitly needed for specific audit requirements. The additional information required is dependent on the type of information (i.e., sensitivity of the data and the environment within which it resides). At a minimum, the organization must audit full-text recording of privileged commands. The organization must maintain audit trails in sufficient detail to reconstruct events to determine the cause and impact of compromise.
SRG-APP-000119-NDM-000236
1 Rule
The Cisco router must be configured to protect audit information from unauthorized modification.
Medium Severity
Audit information includes all information (e.g., audit records, audit settings, and audit reports) needed to successfully audit network device activity. If audit data were to become compromised, then 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 network device must protect audit information from unauthorized modification. This requirement can be achieved through multiple methods, which will depend upon system architecture and design. Some commonly employed methods include ensuring log files receive the proper file system permissions and limiting log data locations. Network devices 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.
SRG-APP-000120-NDM-000237
1 Rule
The Cisco router must be configured to protect audit information from unauthorized deletion.
Medium Severity
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 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 network device 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 receive the proper file system permissions utilizing file system protections, restricting access, and backing up log data to ensure log data is retained. Network devices providing a user interface to audit data will leverage user permissions and roles identifying the user accessing the data and the corresponding rights the user enjoys in order to make access decisions regarding the deletion of audit data.
SRG-APP-000133-NDM-000244
1 Rule
The Cisco router must be configured to limit privileges to change the software resident within software libraries.
Medium Severity
Changes to any software components of the network device can have significant effects on the overall security of the network. Therefore, only qualified and authorized individuals should be allowed administrative access to the network device for implementing any changes or upgrades. If the network device were to enable non-authorized users to make changes to software libraries, those changes could be implemented without undergoing testing, validation, and approval.
SRG-APP-000142-NDM-000245
1 Rule
The Cisco router must be configured to prohibit the use of all unnecessary and nonsecure functions and services.
High Severity
Network devices 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 network device 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. Some network devices have capabilities enabled by default; if these capabilities are not necessary, they must be disabled. If a particular capability is used, then it must be documented and approved.
SRG-APP-000148-NDM-000346
1 Rule
The Cisco router must be configured with only one local account to be used as the account of last resort in the event the authentication server is unavailable.
Medium Severity
Authentication for administrative (privileged level) access to the device is required at all times. An account can be created on the device's local database for use when the authentication server is down or connectivity between the device and the authentication server is not operable. This account is referred to as the account of last resort since it is intended to be used as a last resort and when immediate administrative access is absolutely necessary. The account of last resort logon credentials must be stored in a sealed envelope and kept in a safe. The safe must be periodically audited to verify the envelope remains sealed. The signature of the auditor and the date of the audit should be added to the envelope as a record. An alternative to using a sealed envelope in a safe would be credential files, separated by technology, located in a secured location on a file server, with the files only accessible to those administrators authorized to use the accounts of last resort, and access to that location monitored by a central log server. Administrators should secure the credentials and disable the root account (if possible) when not needed for system administration functions.
SRG-APP-000164-NDM-000252
1 Rule
The Cisco router must be configured to enforce a minimum 15-character password length.
Medium Severity
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 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.
SRG-APP-000166-NDM-000254
1 Rule
The Cisco router must be configured to enforce password complexity by requiring that at least one uppercase character be used.
Medium Severity
Use of a complex passwords helps to increase the time and 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. Password complexity is one factor of several that determine how long it takes to crack a password. The more complex the password is, the greater the number of possible combinations that need to be tested before the password is compromised. Multifactor authentication (MFA) is required for all administrative and user accounts on network devices, except for an account of last resort and (where applicable) a root account. Passwords should only be used when MFA using PKI is not available, and for the account of last resort and root account.
SRG-APP-000167-NDM-000255
1 Rule
The Cisco router must be configured to enforce password complexity by requiring that at least one lowercase character be used.
Medium Severity
Use of a complex password helps to increase the time and 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. Password complexity is one factor of several that determine how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. Multifactor authentication (MFA) is required for all administrative and user accounts on network devices, except for an account of last resort and (where applicable) a root account. Passwords should only be used when MFA using PKI is not available, and for the account of last resort and root account.
SRG-APP-000168-NDM-000256
1 Rule
The Cisco router must be configured to enforce password complexity by requiring that at least one numeric character be used.
Medium Severity
Use of a complex password helps to increase the time and 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. Password complexity is one factor of several that determine how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. Multifactor authentication (MFA) is required for all administrative and user accounts on network devices, except for an account of last resort and (where applicable) a root account. Passwords should only be used when MFA using PKI is not available, and for the account of last resort and root account.
SRG-APP-000169-NDM-000257
1 Rule
The Cisco router must be configured to enforce password complexity by requiring that at least one special character be used.
Medium Severity
Use of a complex password helps to increase the time and 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. Password complexity is one factor of several that determine how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. Multifactor authentication (MFA) is required for all administrative and user accounts on network devices, except for an account of last resort and (where applicable) a root account. Passwords should only be used when MFA using PKI is not available, and for the account of last resort and root account.
SRG-APP-000170-NDM-000329
1 Rule
The Cisco router must be configured to require that when a password is changed, the characters are changed in at least eight of the positions within the password.
Medium Severity
If the application allows the user to consecutively reuse extensive portions of passwords, this increases the chances of password compromise by increasing the window of opportunity for attempts at guessing and brute-force attacks. The number of changed characters refers to the number of changes required with respect to the total number of positions in the current password. In other words, characters may be the same within the two passwords; however, the positions of the like characters must be different. Multifactor authentication (MFA) is required for all administrative and user accounts on network devices, except for an account of last resort and (where applicable) a root account. Passwords should only be used when MFA using PKI is not available, and for the account of last resort and root account.
SRG-APP-000171-NDM-000258
1 Rule
The Cisco router must only store cryptographic representations of passwords.
High Severity
Passwords need to be protected at all times, and encryption is the standard method for protecting passwords. If passwords are not encrypted, they can be plainly read (i.e., clear text) and easily compromised. Network devices must enforce cryptographic representations of passwords when storing passwords in databases, configuration files, and log files. Passwords must be protected at all times; using a strong one-way hashing encryption algorithm with a salt is the standard method for providing a means to validate a password without having to store the actual password. Performance and time required to access are factors that must be considered, and the one way hash is the most feasible means of securing the password and providing an acceptable measure of password security. If passwords are stored in clear text, they can be plainly read and easily compromised. In many instances, verifying the user knows a password is performed using a password verifier. In its simplest form, a password verifier is a computational function that is capable of creating a hash of a password and determining if the value provided by the user matches the stored hash.
SRG-APP-000190-NDM-000267
1 Rule
The Cisco router must be configured to terminate all network connections associated with device management after five minutes of inactivity.
High Severity
Terminating an idle session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended. In addition, quickly terminating an idle session will also free up resources committed by the managed network element. Terminating network connections associated with communications sessions includes, for example, de-allocating associated TCP/IP address/port pairs at the operating system level, or de-allocating networking assignments at the application level if multiple application sessions are using a single, operating system-level network connection. This does not mean that the device terminates all sessions or network access; it only ends the inactive session and releases the resources associated with that session.
SRG-APP-000319-NDM-000283
1 Rule
The Cisco router must be configured to automatically audit account enabling actions.
Medium Severity
Once an attacker establishes initial 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 enable a new or disabled account. Notification of account enabling is one method for mitigating this risk. A comprehensive account management process will ensure an audit trail which documents the creation of application user accounts and notifies administrators and Information System Security Officers (ISSO). Such a process greatly reduces the risk that accounts will be surreptitiously created and provides logging that can be used for forensic purposes.
SRG-APP-000357-NDM-000293
1 Rule
The Cisco router must be configured to allocate audit record storage capacity in accordance with organization-defined audit record storage requirements.
Medium Severity
In order to ensure network devices have a sufficient storage capacity in which to write the audit logs, they need to be able to allocate audit record storage capacity. The task of allocating audit record storage capacity is usually performed during initial device setup if it is modifiable. The value for the organization-defined audit record storage requirement will depend on the amount of storage available on the network device, the anticipated volume of logs, the frequency of transfer from the network device to centralized log servers, and other factors.
SRG-APP-000360-NDM-000295
1 Rule
The Cisco router must be configured to generate an alert for all audit failure events.
Medium Severity
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. 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).
SRG-APP-000373-NDM-000298
1 Rule
The Cisco router must be configured to synchronize its clock with the primary and secondary time sources using redundant authoritative time sources.
Medium Severity
The loss of connectivity to a particular authoritative time source will result in the loss of time synchronization (free-run mode) and increasingly inaccurate time stamps on audit events and other functions. Multiple time sources provide redundancy by including a secondary source. Time synchronization is usually a hierarchy; clients synchronize time to a local source while that source synchronizes its time to a more accurate source. The network device must utilize an authoritative time server and/or be configured to use redundant authoritative time sources. This requirement is related to the comparison done in CCI-001891. DOD-approved solutions consist of a combination of a primary and secondary time source using a combination or multiple instances of the following: a time server designated for the appropriate DOD network (NIPRNet/SIPRNet); United States Naval Observatory (USNO) time servers; and/or the Global Positioning System (GPS). The secondary time source must be located in a different geographic region than the primary time source.
SRG-APP-000395-NDM-000310
1 Rule
The Cisco router must be configured to authenticate SNMP messages using a FIPS-validated Keyed-Hash Message Authentication Code (HMAC).
Medium Severity
Without authenticating devices, unidentified or unknown devices may be introduced, thereby facilitating malicious activity. Bidirectional authentication provides stronger safeguards to validate the identity of other devices for connections that are of greater risk. A local connection is any connection with a device communicating without the use of a network. A network connection is any connection with a device that communicates through a network (e.g., local area or wide area network, Internet). A remote connection is any connection with a device communicating through an external network (e.g., the Internet). Because of the challenges of applying this requirement on a large scale, organizations are encouraged to only apply the requirement to those limited number (and type) of devices that truly need to support this capability.
SRG-APP-000395-NDM-000310
1 Rule
The Cisco router must be configured to encrypt SNMP messages using a FIPS 140-2 approved algorithm.
Medium Severity
Without the strong encryption that is provided by the SNMP Version 3 User-based Security Model (USM), an unauthorized user can gain access to network management information that can be used to create a network outage.
SRG-APP-000395-NDM-000347
1 Rule
The Cisco router must be configured to authenticate Network Time Protocol (NTP) sources using authentication that is cryptographically based.
Medium Severity
If Network Time Protocol is not authenticated, an attacker can introduce a rogue NTP server. This rogue server can then be used to send incorrect time information to network devices, which will make log timestamps inaccurate and affect scheduled actions. NTP authentication is used to prevent this tampering by authenticating the time source.
SRG-APP-000411-NDM-000330
1 Rule
The Cisco router must be configured to use FIPS-validated Keyed-Hash Message Authentication Code (HMAC) to protect the integrity of remote maintenance sessions.
High Severity
Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied upon to provide confidentiality or integrity, and DoD data may be compromised. Nonlocal maintenance and diagnostic activities are those activities conducted by individuals communicating through a network, either an external network (e.g., the Internet) or an internal network. Currently, HMAC is the only FIPS-approved algorithm for generating and verifying message/data authentication codes in accordance with FIPS 198-1. Products that are FIPS 140-2 validated will have an HMAC that meets specification; however, the option must be configured for use as the only message authentication code used for authentication to cryptographic modules.
SRG-APP-000412-NDM-000331
1 Rule
The Cisco router must be configured to implement cryptographic mechanisms to protect the confidentiality of remote maintenance sessions.
High Severity
This requires the use of secure protocols instead of their unsecured counterparts, such as SSH instead of telnet, SCP instead of FTP, and HTTPS instead of HTTP. If unsecured protocols (lacking cryptographic mechanisms) are used for sessions, the contents of those sessions will be susceptible to eavesdropping, potentially putting sensitive data (including administrator passwords) at risk of compromise and potentially allowing hijacking of maintenance sessions.
SRG-APP-000435-NDM-000315
1 Rule
The Cisco router must be configured to protect against known types of denial-of-service (DoS) attacks by employing organization-defined security safeguards.
Medium Severity
DoS is a condition when a resource is not available for legitimate users. When this occurs, the organization either cannot accomplish its mission or must operate at degraded capacity. This requirement addresses the configuration of network devices to mitigate the impact of DoS attacks that have occurred or are ongoing on device availability. For each network device, known and potential DoS attacks must be identified and solutions for each type implemented. A variety of technologies exist to limit or, in some cases, eliminate the effects of DoS attacks (e.g., limiting processes or restricting the number of sessions the device opens at one time). Employing increased capacity and bandwidth, combined with service redundancy, may reduce the susceptibility to some DoS attacks. The security safeguards cannot be defined at the DoD level because they vary according to the capabilities of the individual network devices and the security controls applied on the adjacent networks (e.g., firewalls performing packet filtering to block DoS attacks).
SRG-APP-000499-NDM-000319
1 Rule
The Cisco router must be configured to generate log records when administrator privileges are deleted.
Medium Severity
Without generating audit records that are specific to the security and mission needs of the organization, 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 network device (e.g., module or policy filter).
SRG-APP-000503-NDM-000320
1 Rule
The Cisco router must be configured to generate audit records when successful/unsuccessful logon attempts occur.
Medium Severity
Without generating audit records that are specific to the security and mission needs of the organization, 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 network device (e.g., module or policy filter).
SRG-APP-000504-NDM-000321
1 Rule
The Cisco router must be configured to generate log records for privileged activities.
Medium Severity
Without generating audit records that are specific to the security and mission needs of the organization, 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 network device (e.g., module or policy filter).
SRG-APP-000516-NDM-000336
1 Rule
The Cisco router must be configured to use at least two authentication servers for the purpose of authenticating users prior to granting administrative access.
High Severity
Centralized management of user accounts and authentication increases the administrative access to the router. This control is particularly important protection against the insider threat. With robust centralized management, audit records for administrator account access to the organization's network devices can be more readily analyzed for trends and anomalies. The alternative method of defining administrator accounts on each device exposes the device configuration to remote access authentication attacks and system administrators with multiple authenticators for each network device.
SRG-APP-000516-NDM-000340
1 Rule
The Cisco router must be configured to back up the configuration when changes occur.
Medium Severity
System-level information includes default and customized settings and security attributes, including ACLs that relate to the network device configuration, as well as software required for the execution and operation of the device. Information system backup is a critical step in ensuring system integrity and availability. If the system fails and there is no backup of the system-level information, a denial of service condition is possible for all who utilize this critical network component. This control requires the network device to support the organizational central backup process for system-level information associated with the network device. This function may be provided by the network device itself; however, the preferred best practice is a centralized backup rather than each network device performing discrete backups.
SRG-APP-000516-NDM-000344
1 Rule
The Cisco router must be configured to obtain its public key certificates from an appropriate certificate policy through an approved service provider.
Medium Severity
For user certificates, each organization obtains certificates from an approved, shared service provider, as required by OMB policy. For federal agencies operating a legacy public key infrastructure cross-certified with the Federal Bridge Certification Authority at medium assurance or higher, this Certification Authority (CA) will suffice.
SRG-APP-000516-NDM-000350
1 Rule
The Cisco router must be configured to send log data to at least two syslog servers for the purpose of forwarding alerts to the administrators and the ISSO.
High Severity
The aggregation of log data kept on a syslog server can be used to detect attacks and trigger an alert to the appropriate security personnel. The stored log data can used to detect weaknesses in security that enable the network IA team to find and address these weaknesses before breaches can occur. Reviewing these logs, whether before or after a security breach, are important in showing whether someone is an internal employee or an outside threat.
SRG-APP-000516-NDM-000351
1 Rule
The Cisco router must be running an IOS release that is currently supported by Cisco Systems.
High Severity
Network devices running an unsupported operating system lack current security fixes required to mitigate the risks associated with recent vulnerabilities. Running a supported release also enables operations to maintain a stable and reliable network provided by improved quality of service and security features.