When TLS Hacks You

Presented at Black Hat USA 2020 Virtual, Aug. 5, 2020, 2:30 p.m. (40 minutes)

Lots of people try to attack the security of TLS. But, what if we use TLS to attack other things? It's a huge standard, and it turns out that features intended to make TLS fast have also made it useful as an attack vector.

Among other things, these features provide a lot of flexibility for Server-Side Request Forgery (SSRF). While past work using HTTPS URLs in SSRF has relied upon platform-specific bugs such as SNI injection, we can go further. In this talk, I present a novel, cross-platform way of leveraging TLS to target internal services.

Uniquely, these attacks are more effective the more comprehensively a platform supports modern TLS, so won't go away with library upgrades. It is also unlikely that the TLS spec will change overnight at the whim of a random security researcher. Instead, we need to walk through scenarios and dispel common assumptions so the audience can make informed code and infrastructure decisions. Of course, the best way to do so is with demos!


Presenters:

  • Joshua Maddux - Security Engineer, Latacora
    Joshua Maddux started out as a software engineer. After a few years, having introduced his share of bugs to the world, he started hunting for vulnerabilities in his own code and elsewhere. At PKC Security he gained additional experience in software development and white-box penetration testing and gave his first ever conference talk at Black Hat USA on a series of systemic SSRF vulnerabilities in sites supporting Apple Pay. Now on the Appsec team at Latacora, he helps advise startups in building secure products. Aside from work for clients, Joshua is also active in the bug bounty world. His past research has led to security updates in Java, Netflix, Gitlab, United Airlines, Zapier, and others.

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