Help crack Gpcode

Static M.e.

Just saw this posted, interesting and scary stuff if more virus writers started to use good encryption..

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Help crack Gpcode

Aleks June 06, 2008 | 16:50 GMT comment

If you read Vitaly's blogpost yesterday, you'll know that on the 4th June 2008 we detected a new variant of Gpcode, a dangerous file encryptor. Details of the encryption algorithms used by the virus are all in Vitaly's post and the description of Gpcode.ak.
Along with antivirus companies around the world, we're faced with the task of cracking the RSA 1024-bit key. This is a huge cryptographic challenge. We estimate it would take around 15 million modern computers, running for about a year, to crack such a key.

Of course, we don't have that type of computing power at our disposal. This is a case where we need to work together and apply all our collective knowledge and resources to the problem.

So we're calling on you: crytographers, governmental and scientific institutions, antivirus companies, independent researchers…join with us to stop Gpcode. This is a unique project – uniting brain-power and resources out of ethical, rather than theoretical or malicious considerations.

Here are the public keys used by the authors of Gpcode.

The first is used for encryption in Windows XP and higher.


Key type: RSA KeyExchange
bitlength: 1024
RSA exponent: 00010001
RSA modulus:
c0c21d693223d68fb573c5318982595799d2d295ed37da38be41ac8486ef900a
ee78b4729668fc920ee15fe0b587d1b61894d1ee15f5793c18e2d2c8cc64b053
9e01d088e41e0eafd85055b6f55d232749ef48cfe6fe905011c197e4ac6498c0
e60567819eab1471cfa4f2f4a27e3275b62d4d1bf0c79c66546782b81e93f85d
The second is used for encryption in versions of Windows prior to XP.


Key type: RSA KeyExchange
bitlength: 1024
RSA exponent: 00010001
RSA modulus:
d6046ad6f2773df8dc98b4033a3205f21c44703da73d91631c6523fe73560724
7cc9a5e0f936ed75c75ac7ce5c6ef32fff996e94c01ed301289479d8d7d708b2
c030fb79d225a7e0be2a64e5e46e8336e03e0f6ced482939fc571514b8d7280a
b5f4045106b7a4b7fa6bd586c8d26dafb14b3de71ca521432d6538526f308afb
The RSA exponent for both keys is 0x10001 (65537).

The information above is sufficient to start factoring the key. A specially created utility could be of great help in factoring.

We're happy to provide additional information to anyone involved in stopping Gpcode. To keep everyone up to date, we've set up a dedicated forum.

Martyr

yeah, its interesting and we are definitely gonna see more of the same in the future, i'm reading up on this stuff at the moment and it seems cryptovirology isn't a new concept - the idea of extortion with crypto has been around for atleast 20 or more years - the first use of RSA in a virus that i'm aware of was by Vecna with Hybris (released around 2001) - although this was more PoC than anything else. (it wasn't extortion, but used to verify plugin modules)

another example of using crypto is serotonin by benny.

one thing that has been discussed for years and implemented in "lab" conditions - but not by people you'd expect - is kleptography.

just like a good burglar wouldn't enter a house without using gloves, a professional computer attack would employ protocols proven to be secure against network analysis.

take for example shellcode which allows the attacker to use ECDH to exchange symmetric keys for encrypting the entire attack.
how could a network administrator or IDS system possibly identify it in real time?
how could a forensics expert analyse the data after an attack?

Screaming Monkey

I like this little rant about all of this, you mileage may vary..

http://anti-virus-rants.blogspot.com/2008/06/stop-trying-to-decrypt-your-data.html

_CreeD_

I agree with that last article. Cracking the key is only of real benefit to the AV vendors in being able to advertise that they can do it. Anyone with data sensitive enough to have value should be backing it up anyway (let alone have more proactive defenses in place to stop it from happening). It's easy to grenerate and inject new keys into the code so cracking one variant is a waste of time imho.

Martyr

absolutely, SM - the obvious and most sensible thing to do is make backups, and this is would solve the problem, which is probably why extortion with crypto hasn't ever been a huge problem.

on the other hand, kleptography isn't that well used (AFAIK)
most administrators rely on the fact they can view, record and analyse network traffic for malicious activity.

if a malicious attacker gains access to some system, uses ECDH + AES to encrypt everything between the compromised system and himself, how can you deal with that? - thats something we're gonna have to think about.

the traditional backdoor is old too..would it not make more sense to place keys in the crypto components of a system? allowing access whenever you want.

how easy is that to detect?

_CreeD_

Aye, you need to be able to inspect and alert on anomalous traffic, signature based identification will be next to impossible but detection shouldn't be. Standard VPN protocols are easily identified and can be blocked/alerted on by your Firewalls alone, for tunnelled traffic using normally permitted ports you need to rely on packet inspection preferably by a good IPS. It won't tell you what's inside the traffic but so long as the user/affected system has no normal business need to use the same protocols outgoing you can detect and block the anomalies then deal with the infection itself. But yup encryption is going to become the norm (hell IPSec is built into IPv6 ).

Capt'n Midnight

Average Joe wrote: »

absolutely, SM - the obvious and most sensible thing to do is make backups, and this is would solve the problem, which is probably why extortion with crypto hasn't ever been a huge problem.

I can remember in the early days someone sent one of these to AIDS researchers world wide. Scumbag.

Found it - 1989 when AIDS was very scary
http://en.wikipedia.org/wiki/AIDS_(trojan_horse)
http://momusings.blogsome.com/2005/05/24/


Have to agree that cracking the encryption on one virus would be a waste of time unless it could prevent most further occurance. Perhaps if they announced a minimum term of 1 day per computer year it took to break the encryption ??
Other wise is just another indirect DoS attack. You could nearly imagine a company like Enron trying this.

And there is nothing stopping them using an abritarly long key in the future.