Thursday, August 31, 2017

The TLS 1.3 Controversy

Rich Mogull:

What exactly is the security weakness TLS 1.3 eliminates? – Version 1.3 eliminates support for an older way of setting up encrypted connections using a master key. It could enable someone with a copy of the master key to sniff all encrypted traffic. They could also decrypt any previously recorded traffic protected with that key. The proposed updates to TLS use a different key for every connection, so there is no master key which could allow unrestricted monitoring. We call this Perfect Forward Secrecy, if you want to look it up.

This is a pretty big weakness, which has been used in attacks. Unfortunately it’s also used by legitimate security tools for more efficient monitoring.


TLS 1.2 is still completely supported and will be for a long time. As online services start adopting TLS 1.3, organizations which rely on passive sniffing of encrypted connections may start losing visibility into those connections. Organizations which want to maintain this visibility will need to update their tools and techniques.

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