ForeScout CounterACT ALG Security Technical Implementation Guide

Display of a standardized and approved use notification before granting access to the network ensures privacy and security notification verbiage used is consistent with DoD requirements. System use notifications are required only for access via logon interfaces with human users and are not required when such human interfaces do not exist, for example, with CounterACT guest access function. This requirement applies to network elements that have the concept of a user account and have the logon function residing on the network element. This requirement is not for access to the device itself, such as with system administrators of CounterACT, but rather is related to the network access control function provided to the users. The banner must be formatted in accordance with DTM-08-060. Use the following verbiage for network elements that can accommodate banners of 1300 characters: "You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details."

Display of a standardized and approved use notification before granting access to the publicly accessible network element 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 and are not required when such human interfaces do not exist. This requirement applies to network elements that have the concept of a user account and have the logon function residing on the network element. The banner must be formatted in accordance with DTM-08-060. Use the following verbiage for network elements that can accommodate banners of 1300 characters: "You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following:

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. Possible audit processing failures also include the inability of ALG to write to the central audit log. While this requirement also applies to the event monitoring system (e.g., Syslog, Security Information and Event Management [SIEM], or SNMP servers), CounterACT can also be configured to send notifications.

User account and privilege validation must be centralized in order to prevent unauthorized access using changed or revoked privileges. CounterACT can implement functions such as traffic filtering, authentication, access, and authorization functions based on computer and user privileges. However, the directory service (e.g., Active Directory or LDAP) must not be installed on CounterACT, particularly if the gateway resides on the untrusted zone of the Enclave.

User authentication can be used as part of the policy filtering rule sets. Some URLs or network resources can be restricted to authenticated users only. Users are prompted by the application or browser for credentials. Authentication service may be provided by CounterACT as an intermediary for the application; however, the authentication credential must be stored in the site's directory services server. This requirement only applies to components where this is specific to the function of the device or has the concept of an organizational user (e.g., proxy capability). This does not apply to authentication for the purpose of configuring the device itself (i.e., device management).

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. A non-privileged account is any account with the authorizations of a non-privileged user. Privileged roles are organization-defined roles assigned to individuals that allow those individuals to perform certain security-relevant functions that ordinary users are not authorized to perform. Security relevant roles include key management, account management, network and system administration, database administration, and web administration. Techniques used to address this include protocols using nonces (e.g., numbers generated for a specific one time use) or challenges (e.g., TLS). Additional techniques include time-synchronous or challenge-response one-time authenticators. This requirement applies to ALGs that provide user authentication intermediary services.

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. This does not apply to audit logs generated on behalf of the device itself (management).

Without reauthentication, users may access resources or perform tasks for which they do not have authorization. In addition to the reauthentication requirements associated with session locks, organizations may require reauthentication of individuals and/or devices in other situations, including (but not limited to) the following circumstances: 1. When authenticators change 2. When roles change 3. When security categories of information systems change 4. When the execution of privileged functions occurs 5. After a fixed period of time 6. Periodically Within the DoD, the minimum circumstances requiring reauthentication are privilege escalation and role changes. This requirement only applies to components where this is specific to the function of the device or has the concept of user authentication (e.g., VPN or ALG capability). This does not apply to authentication for the purpose of configuring the device itself (i.e., device management).

For remote access to non-privileged accounts, the purpose of requiring a device that is separate from the information system gaining access for one of the factors during multifactor authentication is to reduce the likelihood of compromising authentication credentials stored on the system. Multifactor solutions that require devices separate from information systems gaining access include, for example, hardware tokens providing time-based or challenge-response authenticators and smart cards such as the U.S. Government Personal Identity Verification card and the DoD common access card. A privileged account is defined as an information system account with authorizations of a privileged user. Remote access is access to DoD-nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. An example of compliance with this requirement is the use of a one-time password token and PIN coupled with a password; or the use of a CAC/PIV card and PIN coupled with a password.

Off-loading ensures audit information does not get overwritten if the limited audit storage capacity is reached and also protects the audit record in case the system/component being audited is compromised. Off-loading is a common process in information systems with limited audit storage capacity. The audit storage on the ALG is used only in a transitory fashion until the system can communicate with the centralized log server designated for storing the audit records, at which point the information is transferred. However, DoD requires that the log be transferred in real time which indicates that the time from event detection to off-loading is seconds or less. This does not apply to audit logs generated on behalf of the device itself (management).

It is critical that when the network element is 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. When availability is an overriding concern, other approved actions in response to an audit failure are as follows: 1. If the failure was caused by the lack of audit record storage capacity, the network element 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. 2. If audit records are sent to a centralized collection server and communication with this server is lost or the server fails, the network element 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. A NAC is an essential security service and should not be shut down in the event of an audit failure. Redundancy and rollover features of the CounterACT enterprise or a high availability solution should be leveraged. Load balancing and redundancy is a function of the CounterAct enterprise architecture by default.