How to Disable SSL 2.0 and SSL 3.0 in IIS?

Mert Ilis
2 min readMar 17, 2016

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A few years ago some SSL vulnerabilities were discovered and some VERY technical warnings were serviced to internet. You might have came across these warnings about SSL 2 vulnerabilities, SSL 3 vulnerabilities and POODLE Attack problem. Other protocols like TLS 1.0 are not vulnerable at this time. By using this exploit the attacker can inject a JavaScript code and watch/manipulate the encrypted network traffic.

You might have also came here because the PCI compliance programs (like Ssllabs/Ssltest) output that your website has a SSL 3.0 vulnerability.

Anyway, POODLE protocol vulnerability can be easily fixed in Windows environment by doing some registry hacking.

Be careful! After doing these changes your secure website will not be accessible via Internet Explorer 6.0 (who cares!)

First you have to access “Registry Editor”:

  • Start
  • Run
  • Type “regedit
  • Click “OK”

Perform these changes:

Windows Registry Editor Version 5.00[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\DES 56/56]
"Enabled"=dword:00000000
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\NULL]
"Enabled"=dword:00000000
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\RC2 40/128]
"Enabled"=dword:00000000
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\RC2 56/128]
"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
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\RC4 64/128]
"Enabled"=dword:00000000
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\PCT 1.0\Server]
"Enabled"=dword:00000000
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0\Server]
"Enabled"=dword:00000000
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0\Server]
"Enabled"=dword:00000000
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0\Client]
"DisabledByDefault"=dword:00000001
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Client]
"DisabledByDefault"=dword:00000000
"Enabled"=dword:00000001
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Server]
"Enabled"=dword:00000001
"DisabledByDefault"=dword:00000000
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Client]
"DisabledByDefault"=dword:00000000
"Enabled"=dword:00000001
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Server]
"Enabled"=dword:00000001
"DisabledByDefault"=dword:00000000

Restart the machine!!!

After performing these you can test the website’s SSL 3.0 vulnerability by using SSL Labs online tool.

Hope it helps!

Originally published at http://www.weboideas.com on March 17, 2016.

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Mert Ilis
Mert Ilis

Written by Mert Ilis

I’m a software development enthusiast who likes trying different web technologies and adding value to his team.

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