Domain controllers must require LDAP access signing.

From Windows Server 2012/2012 R2 Domain Controller Security Technical Implementation Guide

SV-51140r3_rule Domain controllers must require LDAP access signing.

Vulnerability 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 could 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

If the following registry value does not exist or is not configured as specified, this is a finding: Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \System\CurrentControlSet\Services\NTDS\Parameters\ Value Name: LDAPServerIntegrity Value Type: REG_DWORD Value: 2

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".

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