DEF CON Quals 2018: It's a Me

Category: pwnable      |      Points: 124      |      Solves: 49      |      Challenge files

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> checksec mario
[*] '/home/raywang/ctf/DEFCONQ2018/mario'
Arch: amd64-64-little
RELRO: Full RELRO
Stack: Canary found
NX: NX enabled
PIE: PIE enabled

Summary

This is a classic C++ menu challenge that features a UAF and heap overflow with a vtable pointer overwrite. The main heap techniques involve using a free unsorted bin chunk to leak a libc and heap address, as well as some feng shui to place an object in an overflow-able region on the heap. fortenforge, qzqxq, and I combined to reverse the binary and discover the 3 separate vulnerabilities.

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My Favorite Films of All Time

I discovered my interest in film at the start of college. As an arts reviewer for The Tech, MIT’s student newspaper, I had the luxury of attending advance press screenings of big-name films like Suicide Squad and the final Hobbit film. But more importantly, my reviews cultivated an appreciation for the medium and an insatiable desire to experience all it had to offer. Since then, I’ve devoured films of all genres and eras, directors and actors, cinematographers and writers.

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Formal Verification: The Gap Between Perfect Code and Reality

Thanks to Vlad Brown and Drawings Team for Russian and Uzbek translations.

In Fall 2017, I took MIT’s 6.826, Principles of Computer Systems, taught by Turing Award-winner Butler Lampson, Nickolai Zeldovich, and Frans Kaashoek. Despite its rudimentary title, it’s a grad class on building formally verified systems. Using the proof language Coq, we wrote specifications, implementations, and proofs of toy structures: a remapped disk, an atomic pair of blocks, and a replicated disk. We also read quite a few papers from the state-of-the-art in formal methods.

I went into the class believing that formal verification is the future — the only solution to a world of software ridden with bugs and security issues. But after recent events and a semester of trying to apply formal methods, I’m a serious skeptic. In this post, I’ll discuss why I think formal verification has a long way to go — and why it just doesn’t work right now.

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Formal Reasoning in Coq — a Beginner's Guide

I’m currently taking the Fall 2017 iteration of 6.826, Principles of Computer Systems. This class has been offered in various forms over the years, but this iteration is quite different. It focuses on formal verification of computer systems using Coq, a language for mechanical theorem proving.

The goal of this class is to write the spec, implementation, and proofs for a formally verified RAID filesystem in Coq, then generate Haskell code from it.

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Looking Towards Summer: Concolic Execution, Fuzzy Panda, and More

It’s always bothered me that MIT or MIT Lincoln Lab didn’t submit anything to DARPA’s Cyber Grand Challenge. With all the smart people, such as my advisor, Armando Solar-Lezama, working on program analysis and formal methods (which I currently know nothing about), I would have expected that we could create a strong Cyber Reasoning System worthy of CGC.

That’s sort of what I will be working on this summer at Lincoln and probably writing my thesis on. But I’m very new to the field and have just started diving in.

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Matasano Crypto Challenges, Set 6

The last of the original crypto challenges… here we go!

Challenge 41 Implement unpadded message recovery oracle

Unpadded RSA is homomorphic, meaning that, if operations like multiplication and addition are carried out on ciphertext, it is as if the same operation were applied to the plaintext.

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