GCHQ: Can you crack this code?

UK intelligence agency GCHQ has launched a code cracking competition to help attract new talent.

So i have been trying now for a while and i think i might have gotten somewhere but its probaly no where near where i should be. Any code crackers on ATS wana have a go.

Crack This

reply to post by definity


Thanks for posting this...

EDIT: Im forgetting some basic compSci lessons.

reply to post by definity


Is it a one time pad? If it is, send me the cookies. You are on your own without the cookies. U2U

Remember non carrying math? I'll check your link. But if it is some kind of Puter Crypto,

I'll have Nigel play around with it.

Why should we do that job for free?

reply to post by definity


Pippa Parties

in her Panties

3rd line.

I'll check back in Manana, but this is a great post! S&F to you for the challenge

reply to post by definity


love these, just tagging for later..... nice find

I just read about this and thought it would be an ATS fun challenge, see how many MI5 grade brains we have lurking, s&f OP:

its the same code for evrey one.

i have tried for about 4 and a half hours to crack it no luck but i have got close but since im not math or code cracking expert im not sure if i am close. But in a few of my find i found out of the 160 pair of characters there are 28 0's which is the higest of any number and for some reason there are none starting with 6. i have tried the standard Hex to Ascii but no luck so mabey shifting the numbers from side to side would help. I started writing a program to do ti for me but my coding knowledge is only limited at this point and it was easier to try it by pen and papper.

Interesting puzzle, OP. Thanks for bringing it to members' attention.

Some of the following I found in half an hour's digging on the web, but other parts (for example, the second half of the shell code), I was able to work out myself by a bit of deduction. So I figure if I post what I've got so far then someone far smarter than I will be able to get the _javascript file and solve this fairly quickly.

To begin, you first need to extract the first half of the shellcode by copying the actual bytes of the crypt.png image, but as it's only half of the code you won't get anywhere if you try to run it. The other half of the required shell code is in the "comment" for the image. You can obtain it by hex edit, but it's far easier to just drop the crypt.png image (or its url) into an EXIF viewer.

I used Jeffrey's exif viewer to do the job as it's reliable and I've never had issues with it. (The link shows the actual .png image and the readings for it. Scroll down to see the vital bit, namely the "comment" at the end.)

As you'll see in the above linky, the "comment" reads:

QkJCQjIAAACR2PFtcCA6q2eaC8SR+8dmD/zNzLQC+td3tFQ4qx8O447TDeuZw5P+0SsbEcYR
78jKLw==

That's a base64 encoded string. So, just use a base64 decoder (such as this one at opinionatedgeek [dot] com) and you'll find it begins with BBBB (actually BBBB2, but it's the BBBB that's most important here). Now you use a concat to join this pice of shellcode with the first half of the shellcode. Then, run through the code and you'll find a GET request.

You'll need to download the _javascript file the GET refers to and from there you should be able to get to the solution.

Have fun...

Mike

reply to post by JustMike


Erm...

What?

reply to post by JustMike


oh well. why don't you just give them your source?

good luck hacking this, folks

reply to post by jedi_hamster

Actually, that was not my source, but it's good to have another one for people to work with, so thanks for adding it. (Starred your post. Hope others will check out your links.) I wish I'd known of that one earlier, to be honest! I used several different sites where they're discussing this to glean bits of info, though. There were quite a lot that I didn't even look at in any depth, either.

And your second link: man, wtg!! Now, there's a challenge! As jedi_hamster says, good luck if you can hack it!

And before anyone asks: no, I haven't solved it. It's too tough for me. I just shared what I'd been able to put together up to when I posted. So ignore my first post re running the shellcode as it will only get you to what jedi_hamster's put up in that second link anyway!

Hmmm... I don't think a Brit intelligence agency would want me anyway...

Mike

reply to post by JustMike


well, those folks there are trying with some screwed up python code. i have a feeling i'll give it a try with some quickly hacked tcl code, we'll see if i'll have time for this. after all, it's just a simple virtual machine

someone solved it already:
www.canyoucrackit.co.uk...

the vm code generates an url to some keygen it seems, at least according to the comments on the website i've posted earlier.
www.canyoucrackit.co.uk... - that is keygen.exe, but some parts are obviously missing, so i guess i'll have to hack that vm on my own.

reply to post by definity


I'm not having any luck with that at all. Something about it looks familiar, but I too stupid
to figure it out. I keep thinking the answer is an 8 letter word.

this is what happens after you crack the code :-)

Originally posted by Lady_Tuatha
this is what happens after you crack the code :-)

Next step join GCHQ and monitor ATS and inform on potential threats.

Look Maggie, look what we won

Ref: CYBER/SEC/SPEC/11 PHASE 2
Region: South West
Location: Cheltenham
Salary: £25,446 (GC10) £31,152 (GC9)
Discipline: Cyber
Grade: GC10/GC9
Closing date for applications is 12 December 2011

another crappy wage slave salary kissing government butt

yeah well my C is a bit rusty to compile that code, i dont know too much about cracking adn hacking but hopefully by next year i will. im gonna do some of the security tube qulification and mabey soem ethical hacker and CEH stuff!!!!!

reply to post by Lady_Tuatha


Excellent Job, Why don't you apply and become the new "Bond, Ms.Bond."

You could even be, "stirred but not shaken." Instead of "shaken,but not stirred."

I always thought they had that phrase backwards anyway.