Title

The directory service must be configured to terminate LDAP-based network connections to the directory server after five (5) minutes of inactivity. (Cat III impact)

Discussion

The failure to terminate inactive network connections increases the risk of a successful attack on the directory server. The longer an established session is in progress, the more time an attacker has to hijack the session, implement a means to passively intercept data, or compromise any protections on client access. For example, if an attacker gains control of a client computer, an existing (already authenticated) session with the directory server could allow access to the directory. The lack of confidentiality protection in LDAP-based sessions increases exposure to this vulnerability.

Check Content

Verify the value for MaxConnIdleTime. Open an elevated command prompt. Enter "ntdsutil". At the "ntdsutil:" prompt, enter "LDAP policies". At the "ldap policy:" prompt, enter "connections". At the "server connections:" prompt, enter "connect to server [host-name]". (Where [host-name] is the computer name of the domain controller.) At the "server connections:" prompt, enter "q". At the "ldap policy:" prompt, enter "show values". If the value for MaxConnIdleTime is greater than 300 (the value for five minutes) or it is not specified, this is a finding. Enter "q" at the "ldap policy:" and "ntdsutil:" prompts to exit. Alternately, Dsquery can be used to display MaxConnIdleTime: Open an elevated command prompt. Enter the following command (on a single line). dsquery * "cn=Default Query Policy,cn=Query-Policies,cn=Directory Service, cn=Windows NT,cn=Services,cn=Configuration,dc=[forest-name]" -attr LDAPAdminLimits The quotes are required and dc=[forest-name] is the fully qualified LDAP name of the domain being reviewed (e.g., dc=disaost,dc=mil).

Fix Text

Configure the directory service to terminate LDAP-based network connections to the directory server after five (5) minutes of inactivity. Open an elevated command prompt. Enter "ntdsutil". At the "ntdsutil:" prompt, enter "LDAP policies". At the "ldap policy:" prompt, enter "connections". At the "server connections:" prompt, enter "connect to server [host-name]". (Where [host-name] is the computer name of the domain controller.) At the "server connections:" prompt, enter "q". At the "ldap policy:" prompt, enter "Set MaxConnIdleTime to 300". Enter "Commit Changes" to save. Enter "Show values" to verify changes. Enter "q" at the "ldap policy:" and "ntdsutil:" prompts to exit.

Additional Identifiers

Rule ID: SV-226083r794805_rule

Vulnerability ID: V-226083

Group Title: SRG-OS-000163-GPOS-00072

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.