SquareLemon Blog

stealthier attacks and smarter defending with tls fingerprinting

I am really pleased to announce that I have decided to try my hand at talking at conferences again this year and have a new talk ready “Stealthier Attacks and Smarter Defending with TLS Fingerprinting”. Despite being a talk on TLS (and SSL) there isn’t any complex crypto or mathematics, this is aimed at defenders and attackers rather than cryptographers. Here’s the abstract:

Ever been busted because you man in the middle software (which does TLS properly) alerted someone to your bad certificate? No more! Want to detect certain types of connections leaving your network, but can’t keep the IP blacklist up to date? This could be the answer.

This talk includes an introduction to both TLS and man in the middle attacks, a walkthrough on what TLS fingerprints contain, how to create your own fingerprints, how we use the fingerprints in several scenarios, a demo, and a discussion of implications and pitfalls.

TLS provides transport security to all manner of connections from legitimate financial transactions to private conversations and malware calling home. The inability to analyse encrypted traffic protects its users, whether they are legitimate or malicious. This talk explores a technique for quickly and passively fingerprinting TLS clients and adapting our responses for the purposes of both attack and defence. Attackers can make automated decisions concerning when to man in the middle a connection and when to let the clients pass through silently, remaining stealthy. Defenders can gain insight into what is making encrypted connections within their networks without access to either endpoints or cryptographic keying material.

I am really excited to have been accepted to speak at SecTor for the second time in October (page for my session here).