Monday, August 17, 2009

Dumpster Diving - XCrypt by Kazuya

For the last week or so I've been repeatedly asked "how do you find these crime-ware tools?" The answer is pretty simple really, I often just use a search engine and focus in on the hacking forums if I'm curious or after some low hanging fruit.

For example, lets take a look at a new(ish) crypter - XCrypt.

I stumbled across this particular crime-ware tool while perusing a popular Spanish hacking site - - which I originally came across when I was looking to see if there were any new (or related) updates to the DIY Octopus Keylogger tool.

Since my Spanish is pretty much non-existent, I need to rely upon one of those online Web translators for these kinds of sites - but then again, it seems that most of the "better" underground malware and hacking sites tend not to be in English anyway. These translators are good enough for my purposes though.

XCrypt caught my eye for a handful of reasons:
  1. It was a 1.0 cryptor (and I wasn't familiar with it)...
  2. It wa hosted on a Spanish site but had German instructions...
  3. It was high up on the first page of the forum.
If you're wondering what a cryptor does - well, generally, you point the tool at a malicious file (e.g. a piece of malware that you've already created - say the output from the DIY Octopus Keylogger), click start, and out pops an auto-unpacking self-encrypted version of the original malware that's (probably) going to bypass any anti-virus detection tools out there.

I was curious about XCrypt though, so I did a little more searching - this time using the keywords "xCrypt Public Kazuya" - and came across yet another hacking forum site - - which had a whole bundle of other Trojans and keyloggers for download (along with satisfied customer reviews).

PortalHacker had a bit of a discussion going on about XCrypt, including the latest anti-virus coverage (which was nothing currently detected it)...

... which isn't precisely unexpected. It's new(ish).

And, to help things along, the site (and review) also included a convenient option to download the tool from one of the free file-hosting providers out there (which is a popular way of distributing these kinds of crime-ware tools). The file was also password protected - to prevent any perimeter or host-based security products from intercepting the file and potentially flagging it as malware (the tool itself - not the output from the tool).

As for the specifics of this particular crime-ware creator tool - I'll leave that to a full-time threat analyst to do his/her stuff and provide the juicy biopsy of XCrypt - even though there were a bundle of postings on the forum congratulating the author of the tool for their skills and eliteness... as well as repeated AV evasion test results.

So, what was next? How about examining the German heritage of this particular tool?... which led to (yet another) hacking forum site - - with a thread covering the XCrypt tool, but this time the thread was started by someone called Kazuya (the author?).

And what do you know, pay dirt, there's an even newer version of the tool available...

... along with new AV test results (only one AV discovers its crypted crime-ware output), and 140 satisfied downloaders.

Most of these kinds of hacking and malware discussion forums have rating systems for contributors (and sellers), and it looks like the last stop in my search found a site that the author of this particular tool likes to hang out - 440 posts and a 5-star site reputation.

And so concludes a brief demonstration in how easy it is to uncover new crime-ware creator kits and tools, and how to get hold of samples to "play" with. This isn't really rocket science kind of stuff.

You may be asking yourself "isn't this all kind of illegal?" and "why aren't these kinds of sites shut down?". Well the answer to that is typically different laws apply in different countries. In most countries it is not illegal to create these kinds of tools, nor is it illegal to discuss their use. In some countries it may be illegal to buy/sell these tools, and in many countries it may be illegal to use them against computers you're not authorized to access - but the net result is that these kinds of information and crime-ware toolsets are out on the Internet for anyone to access (subject to Web filtering policies :-)

1 comment:

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