Kerberos encryption types must be configured to prevent the use of DES encryption suites.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-21954	3.154	SV-32706r2_rule		Medium

Description
Certain encryption types are no longer considered secure. This setting configures a minimum encryption type for Kerberos, preventing the use of the DES encryption suites.

STIG	Date
Windows Server 2008 R2 Domain Controller Security Technical Implementation Guide	2016-12-19

Details

Check Text ( C-60991r2_chk )

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 "Network Security: Configure encryption types allowed for Kerberos" is not set to "Enabled" with only the following selected, this is a finding: RC4_HMAC_MD5 AES128_HMAC_SHA1 AES256_HMAC_SHA1 Future encryption types If DES_CBC_CRC and DES_CBC_MD5 are selected, this is a finding. The policy referenced configures the following registry value: Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\Kerberos\Parameters\ Value Name: SupportedEncryptionTypes Type: REG_DWORD Value: 0x7ffffffc (2147483644)

Fix Text (F-65721r2_fix)
Configure the policy value for Computer Configuration >> Windows Settings >> Security Settings >> Local Policies >> Security Options >> "Network Security: Configure encryption types allowed for Kerberos" to "Enabled" with only the following selected: RC4_HMAC_MD5 AES128_HMAC_SHA1 AES256_HMAC_SHA1 Future encryption types