Jay Bosamiya Software Security Researcher

CTF-Writeups


RSA Chained (Dragon CTF Teaser 2019)

In this challenge, we need to recover a message that is encrypted through 4 different RSA keys, while knowing some of the bits of the private keys. In particular, we are given code that generates 4 different RSA keys (of ~2100 bits each), permutes them, encrypts the flag by each of them in succession, and then provides us the encrypted flag. Additionally, we are given the moduli of the keys, as well as the lower... Read more...

Exploiting Chrome V8: Krautflare (35C3 CTF 2018)

In this challenge, we had to obtain remote code execution, simply by exploiting a 1-day bug that forgot the difference between -0 and +0. This has probably been one of the most difficult, fun, and frustrating bugs I have ever exploited. Read more...

HITCON CTF 2018 - Lost Modulus

Last weekend was HITCON CTF 2018, and it was really awesome! I personally spent time on various super interesting challenges. Below is just one of them that I happened to solve on the first day. I found to be particularly interesting to solve since I never have had a chance to dive into any homomorphic encryption systems before. Read more...

33c3 2016 - Hohoho

This was a great challenge, and I learnt a lot, even though I ended up spending many hours (over 10 hours!) on it. Read more...