FLEXTLS A Tool for Testing TLS Implementations

Benjamin Beurdouche (1) , Antoine Delignat-Lavaud (1) , Nadim Kobeissi (1) , Alfredo Pironti (1) , Karthikeyan Bhargavan (1)

1 PROSECCO - Programming securely with cryptography

We present FLEXTLS, a tool for rapidly prototyping and testing implementations of the Transport Layer Security (TLS) protocol. FLEXTLS is built upon MITLS, a verified implementation of TLS, and hence protocol scenarios written in FLEXTLS can benefit from robust libraries for messaging and cryptography. Conversely, attack scripts in FLEXTLS can be used to evaluate and communicate the impact of new protocol vulnerabilities. FLEXTLS was used to discover recent attacks on TLS implementations, such as SKIP and FREAK, as well as to program the first proof-of-concept demos for FREAK and Logjam. It is also being used to experiment with proposed designs of the upcoming version 1.3 of TLS. Our goal is to create a common platform where protocol analysts and practitioners can easily test TLS implementations and share protocol designs, attacks or proofs.

Mots clés: Transport Layer Security; Cryptographic Pro-tocols; Attacks; Protocol Testing

Domaines: Cryptographie et sécurité [cs.CR]; Informatique et langage [cs.CL]

Benjamin Beurdouche, Antoine Delignat-Lavaud, Nadim Kobeissi, Alfredo Pironti, Karthikeyan Bhargavan. FLEXTLS A Tool for Testing TLS Implementations. 9th USENIX Workshop on Offensive Technologies, WOOT '15, Usenix, Aug 2014, Washington DC, United States. ⟨hal-01295035⟩