Cracking the Lens: Targeting HTTP's Hidden Attack-Surface

Black Hat USA 2017

Presented by: James Kettle
Date: Wednesday July 26, 2017
Time: 16:00 - 16:50
Location: Mandalay Bay GH

Modern websites are browsed through a lens of transparent systems built to enhance performance, extract analytics and supply numerous additional services. This almost invisible attack surface has been largely overlooked for years.

In this presentation, I'll show how to use malformed requests and esoteric headers to coax these systems into revealing themselves and opening gateways into our victim's networks. I'll share how by combining these techniques with a little Bash I was able to thoroughly perforate DoD networks, trivially earn over \$30k in vulnerability bounties, and accidentally exploit my own ISP.

While deconstructing the damage, I'll also showcase several hidden systems it unveiled, including not only covert request interception by the UK's largest ISP, but a substantially more suspicious Columbian ISP, a confused Tor backend, and a system that enabled reflected XSS to be escalated into SSRF. You'll also learn strategies to unblinker blind SSRF using exploit chains and caching mechanisms.

Finally, to further drag these systems out into the light, I'll release Collaborator Everywhere - an open source Burp Suite extension which augments your web traffic with a selection of the best techniques to harvest leads from cooperative websites.

James Kettle

James Kettle is Head of Research at PortSwigger Web Security, where he designs and refines vulnerability detection techniques for Burp Suite's scanner. Recent work has focused on techniques to detect unknown classes of vulnerabilities, and exploiting subtle CORS misconfigurations in bitcoin exchanges. James has extensive experience cultivating novel attack techniques, including server-side RCE via Template Injection, client-side RCE via malicious formulas in CSV exports, and abusing the HTTP Host header to poison password reset emails and server-side caches. He has spoken at numerous prestigious venues including both Black Hat USA and EU, and OWASP AppSec USA and EU.


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