Category: Insomni’hack

Insomni’Hack 2017 – FPS Write-Ups

For the 10th Insomni’Hack anniversary, new hacking challenge categories were available during the CTF. They consisted of social engineering, hacking room, and a multiplayer FPS game.

This article will cover several write-ups for this last category. It is a great occasion to understand quickly some basis of modern game hacking.

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Exploiting a misused C++ shared pointer on Windows 10

In this post I describe a detailed solution to my “winworld” challenge from Insomni’hack CTF Teaser 2017. winworld was a x64 windows binary coded in C++11 and with most of Windows 10 built-in protections enabled, notably AppContainer (through the awesome AppJailLauncher), Control Flow Guard and the recent mitigation policies.

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rbaced – a CTF introduction to grsecurity’s RBAC

Description

rbaced was a pwnable challenge at last week-end’s Insomni’hack Teaser, split in 2 parts: rbaced1 and rbaced2.

TL;DR: grsecurity/PaX can prevent introducing executable memory in a process or execute untrusted binaries, and make your life miserable.

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Insomni’hack finals – Hollywood network writeup

You probably saw on many ‘hackers movies’ weird IP address such a 312.5.125.833. On this challenge, you had to connect on a fake IBM mainframe running on this strange IP stack. After the Z/OS banner, you had to get a shell with “L IMS3270”. No guessing here, it’s simply one of the three suggestions. On the READY prompt, you had a bunch of crappy commands extracted from the Swordfish movie. Only FLAG, IFCONFIG worked. FLAG expects an IP address as parameter. Since this mainframe runs on a non-standard IP stack, you can’t simply enter your IPv4 address. So you have to get a look at the IFCONFIG output:

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Insomni’hack finals – smtpwn writeup

This challenge was solved by several teams during the contest, however it seems that most teams didn’t have the intended solution, so here it is 😉
The source, binary and exploit for this challenge can be found on our github here!
smtpwn was a very simple local SMTP service. Basically you write a message to its stdin, and it’ll write a file to /tmp/ with the following content:

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