Riverbed SteelHead CX v8 NDM Security Technical Implementation Guide

Account management functions include: assignment of group or role membership; identifying account type; specifying user access authorizations (i.e., privileges); account removal, update, or termination; and administrative alerts. The network device must be configured to automatically provide account management functions, and these functions must immediately enforce the organization's current account policy. All accounts used for access to the network device are privileged or system-level accounts. Therefore, if account management functions are not automatically enforced, an attacker could gain privileged access to a vital element of the network security architecture. This control does not include emergency administration accounts that provide access to the network device components in case of network failure. There must be only one such locally defined account. All other accounts must be defined. All other accounts must be created and managed on the site's authentication server (e.g., RADIUS, LDAP, or Active Directory). This requirement is applicable to account management functions provided by the network device application. If the function is provided by the underlying OS or an authentication server, it must be secured using the applicable security guide or STIG.

If shared/group account credentials are not terminated when individuals leave the group, the user that left the group can still gain access even though they are no longer authorized. A shared/group account credential is a shared form of authentication that allows multiple individuals to access the network device using a single account. There may also be instances when specific user actions need to be performed on the network device without unique administrator identification or authentication. Examples include system accounts, account of last resort, accounts used for testing/maintenance, and shared secrets that are configured on the administrator's workstation. When users with knowledge of the account of last resort or default accounts are no longer authorized, account credentials must be changed in accordance with DoD policy.

The Monitor and Shark accounts which are default group accounts with shared credentials. Monitor and Shark accounts are not enabled by default, but cannot be deleted since these network tools are designed to look for that account. Monitor is a read-only account for auditor's configuration management. Shark is used to access packet captures. If the credentials for these accounts are changed, the function of the system will not be adversely impacted.

An authorized insider or individual who maliciously creates a local account could gain immediate access from a remote location to privileged information on a critical security device. Sending an alert to the administrators and ISSO when this action occurs greatly reduces the risk that accounts will be surreptitiously created. RiOS can be configured to send an SNMP trap to the SNMP server. It also sends a message to the Syslog and the local log. Either of these methods results in an alert that can be forwarded to authorized accounts.

To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Network devices use access control policies and enforcement mechanisms to implement this requirement. Access control policies include identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the network device to control access between administrators (or processes acting on behalf of administrators) and objects (e.g., device commands, files, records, processes) in the network device.

By limiting the number of failed login attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-forcing, is reduced.

By limiting the number of failed login attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-forcing, is reduced.

By limiting the number of failed login 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.

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.

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 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. Recommended best practice for authentication and authorization is to leverage an AAA server (e.g., TACACS or RADIUS). Password of Last Resort is not affected by this requirement. Note that this is a hidden CLI command. Access to the device management console is not affected by this command.

Automatic session termination addresses the termination of administrator-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 an administrator (or process acting on behalf of a user) accesses a network device. Such administrator sessions can be terminated (and thus terminate network administrator access) without terminating network sessions. Session termination terminates all processes associated with an administrator's logical session except those processes that are specifically created by the administrator (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. These conditions will vary across environments and network device types.

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.

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).

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.

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), a modern continuation of Greenwich Mean Time (GMT), or local time with an offset from UTC.

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 difficult, if not impossible, to achieve. In addition, access to audit records provides information an attacker could use to his or her advantage. To ensure the veracity of audit data, the information system and/or the network device must protect audit information from any and all unauthorized read access. This requirement can be achieved through multiple methods which will depend upon system architecture and design. Commonly employed methods for protecting audit information include least privilege permissions as well as restricting the location and number of log file repositories. Additionally, network devices with user interfaces to audit records should not allow for the unfettered manipulation of or access to those records via the device interface. If the device provides access to the audit data, the device becomes accountable for ensuring 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 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.

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.

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. Network devices providing tools to interface with audit data will leverage user permissions and roles identifying the user accessing the tools and the corresponding rights the user enjoys in order to make access decisions regarding the access to 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 operations on audit data. Network devices providing tools to interface with audit data will leverage user permissions and roles identifying the user accessing the tools and the corresponding rights the user enjoys in order to make access decisions regarding the access to 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.

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 network device (e.g., process, module). Certain specific device 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 device 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 the capability to restrict which roles and individuals can select which events are audited, unauthorized personnel may be able to prevent the auditing of critical events. Misconfigured audits may 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 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.

Without auditing the enforcement of access restrictions against changes to the device configuration, it will be difficult to identify attempted attacks, and an audit trail will not be available for forensic investigation for after-the-fact actions. Enforcement actions are the methods or mechanisms used to prevent unauthorized changes to configuration settings. Enforcement action methods may be as simple as denying access to a file based on the application of file permissions (access restriction). Audit items may consist of lists of actions blocked by access restrictions or changes identified after the fact. For RiOS, all configuration changes authorized or unauthorized are logged in the system logs. Log entries include the user that initiated the configuration change for accountability.

Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks.

The use of authentication servers or other centralized management servers for providing centralized authentication services is required for network device management. Maintaining local administrator accounts for daily usage on each network device without centralized management is not scalable or feasible. Without centralized management, it is likely that credentials for some network devices will be forgotten, leading to delays in administration, which itself leads to delays in remediating production problems and in addressing compromises in a timely fashion.

The use of authentication servers or other centralized management servers for providing centralized authentication services is required for network device management. Maintaining local administrator accounts for daily usage on each network device without centralized management is not scalable or feasible. Without centralized management, it is likely that credentials for some network devices will be forgotten, leading to delays in administration, which itself leads to delays in remediating production problems and in addressing compromises in a timely fashion.

The use of authentication servers or other centralized management servers for providing centralized authentication services is required for network device management. Maintaining local administrator accounts for daily usage on each network device without centralized management is not scalable or feasible. Without centralized management, it is likely that credentials for some network devices will be forgotten, leading to delays in administration, which itself leads to delays in remediating production problems and in addressing compromises in a timely fashion.

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 unused or unnecessary physical and logical ports/protocols on information systems. 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 to conduct official business or to address authorized quality of life issues.

Information system backup is a critical step in maintaining data assurance and availability. Information system and security-related documentation contains information pertaining to system configuration and security settings. If this information were not backed up, and a system failure were to occur, the security settings would be difficult to reconfigure quickly and accurately. Maintaining a backup of information system and security-related documentation provides for a quicker recovery time when system outages occur. This control requires the network device to support the organizational central backup process for user account 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.

A replay attack may enable an unauthorized user to gain access to the application. Authentication sessions between the authenticator and the application validating the user credentials must not be vulnerable to a replay attack. An authentication process resists replay attacks if it is impractical to achieve a successful authentication by recording and replaying a previous authentication message. Techniques used to address this include protocols using nonces (e.g., numbers generated for a specific one-time use) or challenges (e.g., TLS, WS_Security). Additional techniques include time-synchronous or challenge-response one-time authenticators.

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. For network device management, this has been determined to be network management device addresses, SNMP authentication, and NTP authentication.

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. For network device management, this has been determined to be network management device addresses, SNMP authentication, and NTP authentication.

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. For network device management, this has been determined to be network management device addresses, SNMP authentication, and NTP authentication.

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.

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.

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.

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.

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.

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.

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

Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. To meet password policy requirements, passwords need to be changed at specific policy-based intervals. If the network device allows the user to consecutively reuse their password when that password has exceeded its defined lifetime, the end result is a password that is not changed as per policy requirements.

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. Network devices utilizing encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules. FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets DoD requirements. Note that adding the FIPS 140-2 licenses incurs a cost from the vendor for support for FIPS mode/module.

There are security-related issues arising from software brought into the network device specifically for diagnostic and repair actions (e.g., a software packet sniffer installed on a device in order to troubleshoot system traffic, or a vendor installing or running a diagnostic application in order to troubleshoot an issue with a vendor-supported device). If maintenance tools are used by unauthorized personnel, they may accidentally or intentionally damage or compromise the system. This requirement addresses security-related issues associated with maintenance tools used specifically for diagnostic and repair actions on organizational network devices. Maintenance tools can include hardware, software, and firmware items. Maintenance tools are potential vehicles for transporting malicious code, either intentionally or unintentionally, into a facility and subsequently into organizational information systems. Maintenance tools can include, for example, hardware/software diagnostic test equipment and hardware/software packet sniffers. This requirement does not cover hardware/software components that may support information system maintenance yet are a part of the system (e.g., the software implementing "ping," "ls," "ipconfig," or the hardware and software implementing the monitoring port of an Ethernet switch).

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 manipulation, potentially allowing alteration and hijacking of maintenance sessions.

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.

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.

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 will suffice.

Sequentially generated session IDs can be easily guessed by an attacker. Employing the concept of randomness in the generation of unique session identifiers helps to protect against brute-force attacks to determine future session identifiers. Unique session IDs address man-in-the-middle attacks, including session hijacking or insertion of false information into a session. If the attacker is unable to identify or guess the session information related to pending application traffic, they will have more difficulty in hijacking the session or otherwise manipulating valid sessions. This requirement is applicable to devices that use a web interface for device management. Recommended best practice is that the FIPS license be installed and utilized.

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 (for example, firewalls performing packet filtering to block DoS attacks).

By immediately displaying an alarm message, potential security violations can be identified more quickly even when administrators are not logged into the network device. An example of a mechanism to facilitate this would be through the utilization of SNMP traps.

Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state. Additionally, sensitive account information must not be revealed through error messages to unauthorized personnel or their designated representatives.