Codehead's Corner
Random ramblings on hacking, coding, fighting with infrastructure and general tech
Posted: 17 Apr 2016 by Codehead
2 minute read

Challenge:

Welcome to Vertinet.

This problem follows the same specifications as the previous Verticode problem, except that you have to solve many of them by developing a client to communicate with the server available at problems1.2016q1.sctf.io:50000. Good luck.


Categories: Hacking CTF
Posted: 17 Apr 2016 by Codehead
3 minute read

This was a nice little challenge from sCTF 2016. I’m trying to work on more tricky stuff, but this one looked like fun and I couldn’t resist.

Challenge:

Welcome to Verticode, the new method of translating text into vertical codes.


Categories: Hacking CTF
Posted: 5 Apr 2016 by Codehead
4 minute read

Due the age of some of my email accounts and the stupid things I did when I was less careful with my contact details, I have a constant flow of spam and malware to some parts of my inbox. This is a good thing because I get to pick stuff apart and find out what’s going on in the shady world of digital con artists.

A few weeks ago I received several emails claiming to be important final demands. The messages urged me to view an attached document, which was a JavaScript file. That’s a pretty feeble attempt at phishing, but I guess some people might fall for it. I was interested to see what the script was actually going to do, so I tried to view the content. My mail client quite rightly denied me access to the file, even when I tried to bypass the blocks and warnings. In the end I had to go to the server and pull the attachment manually.


Categories: Malware Teardown
Posted: 27 Mar 2016 by Codehead
7 minute read

I only managed one task in the 2016 VolgaCTF, but it was a fun one. Coding a tic tac toe bot.

Challenge:

Tic-Tac-Toe

An important step towards the strong AI is the ability of an artificial agent to solve a well-defined problem. 
A project by the name 'tic-tac-toe' was one of such test problems. It's still up...

nc tic-tac-toe.2016.volgactf.ru 45679

Categories: Hacking CTF
Posted: 22 Feb 2016 by Codehead
2 minute read

Challenge:

EquationSolver (exp60)

Description:

I created a program for an unsolveable equation system. My friend somehow forced it to solve the equations. Can you tell me how he did it?


Categories: Hacking CTF
Posted: 21 Feb 2016 by Codehead
3 minute read

Challenge:

File Checker (rev60)

Description:

My friend sent me this file. He told that if I manage to reverse it, I’ll have access to all his devices. My misfortune that I don’t know anything about reversing :/


Categories: Hacking CTF
Posted: 21 Feb 2016 by Codehead
2 minute read

Challenge:

FlagStore (exp70)

Description:

Here’s the ultimate flag store. Store and retrieve your flags whenever you want.


Categories: Hacking CTF
Posted: 21 Feb 2016 by Codehead
2 minute read

Challenge:

It’s Prime Time! (code60)

Description: We all know that prime numbers are quite important in cryptography. Can you help me to find some?

Service: 188.166.133.53:11059

Solution:

Running netcat against the address gave the following output:

> nc 188.166.133.53 11059
Hi, you know that prime numbers are important, don't you? 
Help me calculating the next prime!
Level 1.: Find the next prime number after 5:

Categories: Hacking CTF
Posted: 21 Feb 2016 by Codehead
2 minute read

I haven’t done much work with Ruby, but this little challenge from the Internetwache CTF looked interesting.

Challenge:

Ruby’s count (exp50)

Description: Hi, my name is Ruby. I like converting characters into ascii values and then calculating the sum.

Service: 188.166.133.53:12037

Solution

The first thing to do was to poke the service using netcat:

> nc 188.166.133.53 12037
Let me count the ascii values of 10 characters:
> 123
WRONG!!!! Only 10 characters matching /^[a-f]{10}$/ !

Categories: Hacking CTF
Posted: 7 Feb 2016 by Codehead
3 minute read

I hadn’t played SharifCTF before, but these guys put on a good competition.

Unfortunately I had other commitments, but I managed to spend a little bit of time looking at some of the challenges.

dMd was a reverse engineering challenge worth 50 points. A binary was provided with the description:

Flag is : The valid input.

file told me that the binary was an x86-64 ELF, so I threw it at my Fedora install and pulled up the disassembly in IDA.


Categories: CTF Hacking
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