MMA CTF 2016::Judgement::Pwn-50

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After opening the binary up in IDA, it was pretty obvious that we needed to exploit a format string vulnerability. It looks like the flag was declared as a global variable, which means it will have a static address in the .bss Section. This definitely makes our lives easier. See the full writeup here.

CSAW 2015 Finals: Blox (Pwn Adventure Z RE250)

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This year at CSAW Finals, Vector35 contributed an entire NES/Famicom RPG as a challenge category. One challenge was solving the puzzle of the mysterious “Blox Cave” – a room of 24 urns that need to be activated in a certain combination in order to open the door to the flag.

Hack.LU 2014 :: Web 150 :: Hidden in Plain Sight

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For this challenge, we are given the service code to review and find the vulnerability. We locate the function that is generating the sha256 hash: var HMAC_SECRET = ” for (var i=0; i<20; i++) { HMAC_SΕCRET = HMAC_SECRET + (Math.random()+”).substr(2) } function hmac_sign(path) { var hmac = crypto.createHmac(‘sha256’, HMAC_SECRET) hmac.update(path) return hmac.digest(‘hex’) } At first… Read more »

D-CTF 2014 :: Exploit 400 :: Paranormal Activity

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####disclaimer: this CTF involved a lot of guessing, and please note that other challenges were of far lower quality. reader beware. To start this challenge, you had to solve Exploitation 300. 300 consisted of googling a public webapp vulnerability. Once you’ve got a shell as the web user, you’ll see e4.hint in the root dir…. Read more »

D-CTF 2014 :: Bonus 200 :: Final

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For this challenge, we were presented with a website made from the ApPHP Microblog CMS. A quick search on Exploit-DB revealed that there was an existing RCE bug. PHP disable_functions seemed to have an extensive list since exec, shell_exec, and system were all disabled. This leaves only a few commands left to use. It… Read more »

ASIS 2014 :: Web 100 :: Lottery

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For this challenge, you visit the website At the website, there is a basic message about being a specific visitor to win the prize: After checking the cookies, there is a specific value that is written: Visitor=MTUyNDo0NzFjNzVlZTY2NDNhMTA5MzQ1MDJiZGFmZWUxOThmYg%3D%3D This value ends with the entity %3D, which is =, meaning that the value is base64. After… Read more »

CSAW 2014 :: Exploitation 400 :: greenhornd.exe

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[gfm] For this challenge, we’re given an `.exe` file and a server that it’s running on. Running strings on the binary, we see that there’s a lot of text in the program. It’s all instructions on how to get started with Windows exploitation. One block that is particularly interesting is: ~~~ VULNERABLE FUNCTION ——————- Send… Read more »

CSAW 2014 :: Forensics 300 :: Fluffy No More

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I think forensics challenges are generally horrible no fun zones, but Fluffy No More is actually a fun little scavenger hunt through a filesystem. @brad_anton gives us a tarball of the relevant parts of a compromised webserver – a MySQL database dump, /var/log/ , /var/www/ , and all of /etc/. Co-credit for this challenge goes to Alex… Read more »