Title

Windows Server 2019 directory service must be configured to terminate LDAP-based network connections to the directory server after five 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

This applies to domain controllers. It is NA for other systems. Open an elevated "Command Prompt" (run as administrator). 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" (5 minutes) or 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 "Command Prompt (Admin)". 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). If the results do not specify a "MaxConnIdleTime" or it has a value greater than "300" (5 minutes), this is a finding.

Fix Text

Configure the directory service to terminate LDAP-based network connections to the directory server after 5 minutes of inactivity. Open an elevated "Command prompt" (run as administrator). 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-205726r970703_rule

Vulnerability ID: V-205726

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.