Month: December 2015

Disable unsafe ciphers and SSL 2.0/3.0 on your server

One step to improve the security on your servers, would be to disable SSL 2.0 and 3.0 as well as the unsafe ciphers RC4. This can be done using the following registry changes on your server.
Note: When you disable SSL 2.0 and 3.0 on your servers, clients will no longer be able to connect using that. See this post for additional reference.

RC4 Cipher

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\RC4 128/128]
"Enabled"=dword:00000000
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\RC4 40/128]
"Enabled"=dword:00000000
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\RC4 56/128]
"Enabled"=dword:00000000

SSL 2.0 and 3.0

Windows Registry Editor Version 5.00
[HKey_Local_Machine\System\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0]
"Enabled"=dword:00000000
[HKey_Local_Machine\System\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0]
"Enabled"=dword:00000000

References:
https://en.wikipedia.org/wiki/RC_algorithm
https://jesperarnecke.wordpress.com/2014/04/24/web-server-security-ssltls/
https://technet.microsoft.com/en-us/library/dn786418.aspx