7.10 Ensure RC4 Cipher Suites is disabled

Information

RC4 is a stream cipher that has known practical attacks. It is recommended that RC4 be disabled. The only RC4 cipher enabled by default on Server 2012 and 2012 R2 is RC4 128/128.

Rationale:

The use of RC4 may increase an adversaries ability to read sensitive information sent over SSL/TLS.

Solution

To disable RC4 40/128, ensure the following key is absent. If the key is present, ensure it is set to 0.

HKLM\System\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\RC4 40/128\Enabled

To disable RC4 56/128, ensure the following key is absent. If the key is present, ensure it is set to 0.

HKLM\System\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\RC4 56/128\Enabled

To disable RC4 64/128, ensure the following key is absent. If the key is present, ensure it is set to 0.

HKLM\System\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\RC4 64/128\Enabled

To disable RC4 128/128, ensure the following key is set to 0.

HKLM\System\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\RC4 128/128\Enabled

See Also

https://workbench.cisecurity.org/benchmarks/14293

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-13

Plugin: Windows

Control ID: b02b46f102cdb4aafa353162f4c8c411bb7fccad31adcc7f11b1e203d7ca7cdd