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V-225052

CAT II (Medium)

Kerberos encryption types must be configured to prevent the use of DES and RC4 encryption suites.

Rule ID

SV-225052r971535_rule

STIG

Microsoft Windows Server 2016 Security Technical Implementation Guide

Version

V2R10

CCIs

CCI-000803

Discussion

Certain encryption types are no longer considered secure. The DES and RC4 encryption suites must not be used for Kerberos encryption. Note: Organizations with domain controllers running earlier versions of Windows where RC4 encryption is enabled, selecting "The other domain supports Kerberos AES Encryption" on domain trusts, may be required to allow client communication across the trust relationship.

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: \SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\Kerberos\Parameters\

Value Name: SupportedEncryptionTypes

Value Type: REG_DWORD
Value: 0x7ffffff8 (2147483640)

Fix Text

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:

AES128_HMAC_SHA1
AES256_HMAC_SHA1
Future encryption types   

Note: Organizations with domain controllers running earlier versions of Windows where RC4 encryption is enabled, selecting "The other domain supports Kerberos AES Encryption" on domain trusts, may be required to allow client communication across the trust relationship.