Getting Shells from JavaScript: offensive JavaScript techniques for red teamers

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Presented at Kiwicon20138AD 2018 by

Dylan Frichot

AppSec is often very heavily focused on pre-exploitation. Frameworks like BeEF break this norm a little and can be used as tools to move laterally from the browser, to implant malware on adjacent machines. Unfortunately, performing network reconnaissance with JavaScript becomes tricky if the victim doesn't keep the tab open for long. This presentation will discuss relatively new features of JavaScript that have made it easier for sophisticated threat actors to craft JavaScript payloads that target internal network vulnerabilities. We'll also show new reconnaissance techniques traditionally used by red teams, post-malware implant, that can be used to get a foothold onto a network from a browser, pre-malware implant. This presentation will thread together the following techniques to highlight how HTML and JavaScript are more dangerous than ever:CSRF to gain footholds into internal networks; WebRTC for internal network reconnaissance; Service Workers to help reduce the likelihood of arbitrary; JavaScript being detected or halted; Bug Bounty programs as a means of exploitation; Certificate Transparency and other modern sub-domain reconnaissance techniques to refine where to target your CSRF payloads; Looking for vulnerabilities in open source internal tools is much easier to do than looking for vulnerabilities in edge facing assets; We'll also show some real examples of this, crafting external payloads that target internal assets at large companies, and we'll show how responsible disclosure for intranet facing bugs typically gets resolved.