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	WN08-SO-000064	SV-48426r2_rule	ECSC-1	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 8 / 8.1 Security Technical Implementation Guide	2015-06-16

Details

Check Text ( C-45094r2_chk )
Analyze the system using the Security Configuration and Analysis snap-in. (See "Performing Analysis with the Security Configuration and Analysis Snap-in" in the STIG Overview document.) 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 Subkey: \Software\Microsoft\Windows\CurrentVersion\Policies\System\Kerberos\Parameters\ Value Name: SupportedEncryptionTypes Type: REG_DWORD Value: 0x7ffffffc (2147483644)

Check Text ( C-45094r2_chk )

Analyze the system using the Security Configuration and Analysis snap-in. (See "Performing Analysis with the Security Configuration and Analysis Snap-in" in the STIG Overview document.)
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
Subkey: \Software\Microsoft\Windows\CurrentVersion\Policies\System\Kerberos\Parameters\

Value Name: SupportedEncryptionTypes

Type: REG_DWORD
Value: 0x7ffffffc (2147483644)

Fix Text (F-41557r2_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