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Monday, February 13 • 10:45am - 11:15am
Witchcraft Compiler Collection : Towards programs self awareness

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With this presentation, we take a new approach to reverse engineering. Instead of attempting to decompile code, we seek to undo the work of the linker and produce relocatable files, the typical output of a compiler. The main benefit of the later technique over the former being that it does work. Once achieved universal code 'reuse' by relinking those relocatable objects as arbitrary shared libraries, we'll create a form of binary reflection, add scripting capabilities and in memory debugging using a JIT compiler, to attain automated API prototyping and annotation, which, we will argue, constitutes a primary form of binary code self awareness. 

Finally, we'll see how abusing the dynamic linker internals shall elegantly solve a number of complex tasks for us, such as calling a given function within a binary without having to craft a valid input to reach it. The applications in terms of vulnerability exploitation, functional testing, static analysis validation and more generally computer wizardry being tremendous, we'll have fun demoing some new exploits in real life applications, and commit public program profanity, such as turning PEs into ELFs, functional scripting of sshd in memory, stealing crypto routines without even disassembling them, among other things that were never supposed to work. All the above techniques have been implemented into the Wichcraft Compiler Collection, to be released as proper open source software (MIT/BSD-2 licenses).

 


Speakers
JB

Jonathan Brossard

Jonathan Brossard is a computer whisperer from France, although he's been living in Brazil, India, Australia and now lives in San Francisco. For his first conference at DEF CON 16, he hacked Microsoft Bitlocker, McAffee Endpoint and a fair number of BIOS Firmwares. During his second... Read More →


Monday February 13, 2017 10:45am - 11:15am PST
DNA Lounge