Title

The operating system must limit the number of concurrent sessions for each account to an organization-defined number of sessions. (Cat III impact)

Discussion

Limiting the number of allowed users and sessions per user can limit risks related to denial of service attacks. The organization may define the maximum number of concurrent sessions for an information system account globally, by account type, by account, or by a combination thereof. This requirement addresses concurrent sessions for a single information system account and does not address concurrent sessions by a single user via multiple accounts.

Check Content

Identify the organizational requirements for maximum number of sessions and which users must be restricted. If there are no requirements to limit concurrent sessions, this item does not apply. For each user requiring concurrent session restrictions, determine if that user is in the user.[username] project where [username] is the user's account username. # projects [username] | grep user If the output does not include the project user.[username], this is a finding. Determine the project membership for the user. # projects [username] If the user is a member of any project other than default, group.[groupname], or user.[username], this is a finding. Determine whether the max-tasks resource control is enabled properly. # projects -l user.[username] | grep attribs If the output does not include the text: attribs: project.max-tasks=(privileged,[MAX],deny) where [MAX] is the organization-defined maximum number of concurrent sessions, this is a finding.

Fix Text

Identify the organizational requirements for maximum number of sessions and which users must be restricted. If there are no requirements to limit concurrent sessions, this item does not apply. The Project Management profile is required. For each user requiring concurrent session restrictions, add the user to the special user.[username] project where [username] is the user's account username where [MAX] is equal to the organizational requirement. # pfexec projadd -K 'project.max-tasks=(privileged,[MAX],deny)' user.[username] Determine the project membership for the user. # projects [username] If the user is a member of any projects other than default, group.[groupname], or user.[username], remove that project from the user's account. The root role is required. # pfedit /etc/user_attr Locate the line containing the user's username. Remove any project=[projectname] entries from the fifth field. # pfedit /etc/project Locate the line containing the user's username in a project other than default, group.[groupname], or user.[username], and remove the user from the project's entry or entries from the fourth field.

Additional Identifiers

Rule ID: SV-216130r603268_rule

Vulnerability ID: V-216130

Group Title: SRG-OS-000027

Expert Comments

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