The use of DES encryption suites must not be allowed for Kerberos encryption.

From Windows Server 2012/2012 R2 Member Server Security Technical Implementation Guide

Part of Kerberos Encryption Types

Associated with: CCI-000803

SV-53179r2_rule The use of DES encryption suites must not be allowed for Kerberos encryption.

Vulnerability discussion

Certain encryption types are no longer considered secure. By default, Windows 2012/R2 does not use the DES encryption suites. If the configuration of allowed Kerberos encryption suites is needed, the DES encryption suites must not be included.

Check content

Verify whether the registry key below exists. If it does not exist or the value is "0", this is not a finding. If the registry key exists and contains a value other than "0", continue below. The values are determined by the selection of encryption suites in the policy Computer Configuration >> Windows Settings >> Security Settings >> Local Policies >> Security Options >> "Network Security: Configure encryption types allowed for Kerberos". Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\Kerberos\Parameters\ Value Name: SupportedEncryptionTypes Type: REG_DWORD Due to the number of possible combinations that may include the DES encryption types, it is not possible to include all acceptable values as viewed directly in the registry. If the registry key does exist, the value must be converted to binary to determine configuration of specific bits. This will determine whether this is a finding. Note the value for the registry key. For example, when all suites, including the DES suites are selected, the value will be "0x7fffffff (2147483647)". Open the Windows calculator (Run/Search for "calc"). Select "View", then "Programmer". Select "Dword" and either "Hex" or "Dec". Enter the appropriate form of the value found for the registry key (e.g., Hex - enter 0x7fffffff, Dec - enter 2147483647) Select "Bin". The returned value may vary in length, up to 32 characters. If the either of 2 right most characters are "1", this is a finding. If the both of 2 right most characters are "0", this is not a finding.

Fix text

The default system configuration does not use DES encryption for Kerberos and supports this requirement. If Kerberos encryption types must be configured, ensure the following are not selected: DES_CBC_CRC DES_CBC_MD5 If the policy for Computer Configuration >> Windows Settings >> Security Settings >> Local Policies >> Security Options >> "Network security: Configure encryption types allowed for Kerberos" is configured, only the following selections are allowed: RC4_HMAC_MD5 AES128_HMAC_SHA1 AES256_HMAC_SHA1 Future encryption types

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