The ALG providing user access control intermediary services must display an explicit logoff message to users indicating the reliable termination of authenticated communications sessions.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-205057	SRG-NET-000519	SRG-NET-000519-ALG-000008	SV-205057r831407_rule	2024-12-04	2

Description
If a user cannot explicitly end a session, the session may remain open and be exploited by an attacker; this is referred to as a zombie session. Users need to be aware of whether or not the session has been terminated. Logoff messages for access, for example, can be displayed after authenticated sessions have been terminated. However, for some types of interactive sessions including, for example, remote logon, information systems typically send logoff messages as final messages prior to terminating sessions. This policy only applies to ALGs (e.g., identity management or authentication gateways) that provide user account services as part of the intermediary services.

Description

If a user cannot explicitly end a session, the session may remain open and be exploited by an attacker; this is referred to as a zombie session. Users need to be aware of whether or not the session has been terminated. Logoff messages for access, for example, can be displayed after authenticated sessions have been terminated. However, for some types of interactive sessions including, for example, remote logon, information systems typically send logoff messages as final messages prior to terminating sessions. This policy only applies to ALGs (e.g., identity management or authentication gateways) that provide user account services as part of the intermediary services.

ℹ️ Check
If the ALG does not provide user access control intermediary services, this is not applicable. Verify the ALG displays an explicit logoff message to users indicating the reliable termination of authenticated communications sessions. If the ALG does not display an explicit logoff message to users indicating the reliable termination of authenticated communications sessions, this is a finding.

✔️ Fix
If user access control intermediary services are provided, configure the ALG to display an explicit logoff message to users indicating the reliable termination of authenticated communications sessions.