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BNAT Hijacking: Repairing Broken Communication Channels
Jonathan Claudius AIDE 2012 (Hacking Illustrated Series InfoSec Tutorial Videos)
BNAT Hijacking: Repairing Broken Communication Channels
Jonathan Claudius
AIDE 2012
NAT “just works” – sometimes in ways we don’t expect. Thanks to broken vendor
implementations and subtle configuration problems, it’s not uncommon to see a
router leaking packets. As it turns out, these packets, even in mangled form,
often represent a missed opportunity. In this presentation we are going
demonstrate how broken communication channels can be repaired to give an
attacker an entirely different functional view of your public facing
infrastructure. If you’re planning on attending this talk, expect to check your
understanding of an "open port” at the door and be ready to discover what your
last penetration test probably missed. A suite of open source tools will also be
released during this presentation that will allow you to identify, weaponize and
exploit communications channels that "never existed", but have been there all
along!
Detailed description: A common example of Broken NAT (BNAT) is found in
asymmetric routing. Asymmetric routing is basically the concept of creating a
logical layer 3 loop in a TCP/IP session between a client and a server. This is
commonly found in complex routing scenarios or situations where mistakes are
"corrected" to make something work without understanding or caring about the
actual flow of traffic.
In many cases, what can happen during asymmetric communication initiation is
that the response traffic can get mangled/nat'd by egress devices to the point
where the connection becomes inoperable but the traffic still makes it back to
the initiator. What I'm doing is taking this inoperable communication channel
and designing a fully usable connection that an attacker could leverage to gain
access to the hidden service which responded but your client failed to
understand the response.
Bio:
Jonathan Claudius is a Security Researcher at Trustwave. He is a member of
Trustwave's SpiderLabs - the advanced security team focused on penetration
testing, incident response, and application security. He has ten years of
experience in the IT industry with the last eight years specializing in
Security. At Trustwave, Jonathan works in the SpiderLabs Research Division where
he focuses on vulnerability research, network exploitation and is the creator of
the BNAT-Suite. Before joining SpiderLabs, Jonathan ran Trustwave¹s Global
Security Operations Center.
Before joining Trustwave, Jonathan was a Network Penetration Tester for a Top 10
Consulting and Accounting firm and worked for a US Department of Defense
contractor in their Communications Electronics Warfare Division. Jonathan holds
a Bachelor of Science in Applied Networking and System Administration from the
Rochester Institute of Technology and is a Certified Information Systems
Security Professional (CISSP).
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