Title

Domain Controllers must require LDAP signing. (Cat II impact)

Discussion

Unsigned network traffic is susceptible to man-in-the-middle attacks where an intruder captures packets between the server and the client and modifies them before forwarding them to the client. In the case of an LDAP server, this means that an attacker can cause a client to make decisions based on false records from the LDAP directory. You can lower the risk of an attacker pulling this off in a corporate network by implementing strong physical security measures to protect the network infrastructure. Furthermore, implementing Internet Protocol security (IPSec) authentication header mode (AH), which performs mutual authentication and packet integrity for Internet Protocol (IP) traffic, can make all types of man-in-the-middle attacks extremely difficult.

Check Content

Analyze the system using the Security Configuration and Analysis snap-in. Expand the Security Configuration and Analysis tree view. Navigate to Local Policies -> Security Options. If the value for "Domain Controller: LDAP Server signing requirements" is not set to "Require signing", this is a finding. The policy referenced configures the following registry value: Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \System\CurrentControlSet\Services\NTDS\Parameters\ Value Name: LDAPServerIntegrity Value Type: REG_DWORD Value: 2 Documentable Explanation: If LDAP Signing is not supported by a client, service or application, this must be documented with the IAO with supporting vendor information.

Fix Text

Configure the policy value for Computer Configuration -> Windows Settings -> Security Settings -> Local Policies -> Security Options -> "Domain Controller: LDAP Server signing requirements" to "Require signing".

Additional Identifiers

Rule ID: SV-41837r2_rule

Vulnerability ID: V-4407

Group Title: LDAP Signing Requirements

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