diff --git a/controls/anssi.yml b/controls/anssi.yml index dec9d68c99a8..3303d70295a5 100644 --- a/controls/anssi.yml +++ b/controls/anssi.yml @@ -521,10 +521,22 @@ controls: description: >- Remote user sessions (shell access, graphical clients) must be closed after a certain period of inactivity. + notes: >- + There is no specific capability to check remote user inactivity, but some shells allow the + session inactivity time out to be configured via TMOUT variable. + In OpenSSH < 8.2 the inactivity of the user is implied from the network inactivity. + The server is configured to disconnect sessions if no data has been received within the idle timeout, + regardless of liveness status (ClientAliveCountMax is 0 and ClientAliveInterval is > 0). + In OpenSSH >= 8.2 there is no way to disconnect sessions based on client liveness. + The semantics of "ClientAliveCountMax 0" has changed from "disconnect on first timeout" to + "don't disconnect network inactive sessions". The server either probes for the client liveness + or keeps inactive sessions connected. + automated: yes rules: - accounts_tmout + - var_accounts_tmout=10_min - sshd_set_idle_timeout - - sshd_idle_timeout_value=5_minutes + - sshd_idle_timeout_value=10_minutes - sshd_set_keepalive - id: R30