Birthday attacks against TLS ciphers with 64bit block size vulnerability

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Birthday attacks against TLS ciphers with 64bit block size vulnerability (Sweet32) detected in the HAA server.

Issue Description

The following vulnerability has been detected in the HAA server:

"Birthday attacks against TLS ciphers with 64bit block size vulnerability (Sweet32) "

Legacy block ciphers having a block size of 64 bits are vulnerable to a practical collision attack when used in CBC mode. All versions of the SSL/TLS protocols that support cipher suites that use 3DES as the symmetric encryption cipher are affected. The DES and Triple DES ciphers, as used in the TLS, SSH, and IPSec protocols and other protocols and products, have a birthday bound of approximately four billion blocks, which makes it easier for remote attackers to obtain cleartext data via a birthday attack against a long-duration encrypted session, as demonstrated by an HTTPS session using Triple DES in CBC mode, aka a “Sweet32” attack. The vulnerability was discovered in 2016.

Resolution

We can follow the steps below to solve this vulnerability by specifying the Cipher suites.

  1. Go into the folder: /opt/redislabs/bin
  2. Run the command: 
    ccs-cli hset cluster sentinel_cipher_list 0x003c,0x009c,0x009d,0xc023,0xc027,0xc02f,0xc02b,0xc030,0xc02c,0xcca8,0xcca9,0x5600
  3. Restart sentinel: 
    supervisorctl restart sentinel_service
  4. Do the scan again, check if the vulnerability still persists and share.