Tuesday, 27 September 2011

How To: Mitigate the SSL/TLS Vulnerability for Lotus Domino

I've been doing quite a bit of research into the BEAST (Browser Exploit Against SSL/TLS) vulnerability that security researchers Juliano Rizzo and Thai Duong demonstrated at the ekoparty security conference in Buenos Aires on Friday.

The session at ekoparty revealed the technical details about how the exploit works and the vulnerability it exploits.   The vulnerability has been known for quite a while.

The vulnerability affects SSL/TLS ciphers that use the Cipher Block Chaining (CBC) mode. These include the popular AES and Triple-DES encryption methods.  The easiest way to mitigate the vulnerablity is to switch to an encryption algorithm that doesn't use CBC, like those based on the RC4 stream cipher.

Interestingly enough, Google websites don't use CBC based encryption.  They use the RC4 encryption cipher instead.

 

Domino Server BEAST Mitigation - With Internet Site Documents

  1. In the Domino Administrator Client, open the 'Configuration' tab and expand 'Web' and 'Internet Sites'.

  2. Open the Internet Site Document for the server.

  3. Click on the 'Security' tab.

  4. Under 'SSL Options' section, change the 'Protocol Version' to 'V3.0 only'.

  5. Under the 'SSL Security' section, modify the list of SSL ciphers so that only the following ciphers are selected:


    1. RC4 encryption with 128-bit key and MD5 MAC

    2. RC4 encryption with 128-bit key and SHA-1 MAC

    3. RC4 encryption with 40-bit key and MD5 MAC


  6. Save the Internet Site Document.

  7. Restart the HTTP task.


Domino Server BEAST Mitigation - Without Internet Site Documents

There does not seem to be a way to specify the SSL protocol version for Domino without using Internet Sites.   There is a SSL Protocol Version field on the server document, however it states that it does not apply to the HTTP task.

With that said, I look forward to the day that there is TLS support for Lotus Domino.   (And data-at-rest encryption that is stronger than RC4, but that's for another day.)