Old TLS backward compatibility

The TLS protocol is used to provide privacy and data integrity between two or more communicating computer applications. When secured by TLS, connections between a client and a server have one or more of the following properties:-

1. The connection is private
2. The identity of parties can be authenticated
3. The connection is reliable

Transportation layer came from Secure Socket Layer. A careful configuration of TLS will provide additional privacy-related properties like forwarding secrecy, prevent discloser of encryption keys etc. Some of the clients might use older operating systems or old web browsers. The old cipher suite is used for all clients back to Windows XP/IE6. It method should be used only as a last resort only for the specific clients.

Impact

The impact include:-

• Renegotiation attack
• Downgrade attacks like Logjam and FREAK
• Cross-platform attacks like DROWN
• BEAST attack
• Breach attacks
• POODLE attacks

Mitigation / Precaution

This vulnerability can be fixed by:-

• Changing to the old cipher suit if the client is using Windows XP/IE6.

Written by

Sooraj V Nair

Cyber Security Engineer