Skip to main content

Good news!


ONLY FOR THOSE INFECTED WITH 'CRYPTODEFENSE' MALWARE.

I've found a weakness in the malware samples which would allow me to regenerate the private key! . Now it'd be possible to recover files without paying the crooks a penny (though it's not as easy as it sounds). I won't comment any further as I don't want to alert the cyber-crooks.

Comments

  1. Hello, I am a security researcher as well and I think it's totally true. How do I get in touch with you?

    ReplyDelete

Post a Comment

Popular posts from this blog

Wana Decryptor / WanaCrypt0r

Alright, guys. This is a tough one: However, there's no reason to claim it's impossible to decrypt victims data. These idiots always let something slip through their fingers. Their servers might be found and keys restored to their respective victims. Errors might be found in their code, their key encryption scheme may have some weakness, etc. Let's just let the experts find a way out.

By the way, if you want to temporarily protect your PC from this malware, you may do this.


Working backwards to the seeds! (OUTDATED)

Note: 
This article is technically accurate and it can be applied to rudimentary RSA implementations that only use time retrieval functions as seed as demonstrated by CS Students from Virginia University
However, CryptoDefense uses CrytoAPI which uses a robust PRNG based on process ID, thread ID,  system clock, system time, system counter, memory status, free disk clusters, etc. I dramatically changed the keys recovery approach as soon as I found out the keys were stored on disk. Why keep this article then? Oh, we wanted the crooks to think we were down the wrong path ;)

Do NOT use somebody else's decryption program!
The reason why each key is unique and why you can't use somebody else's decryption program is because this ransomware randomly generates the keys for each victim. If there was a unique private key for everyone, there would be no need to panic!

But the is a problem...

Software alone is technically incapable of generating random numbers in its truest sense. This exp…

CryptoDefense: Keys pair stored on disk!

This little detail slipped through their fingers... TOO LATE!

(I actually hid this post when I understood that it might alert the crooks. But SYMANTEC did!)

This is the exact path where your keys are:


Windows XP
C:\Documents and Settings\<USERNAME>\Application Data\Microsoft\Crypto\RSA\S-1-5-2... Windows 7
X:\Users\<USERNAME>\AppData\Roaming\Microsoft\Crypto\RSA\S-1-5-21... (X stands for your hard-disk letter, which is commonly C in most computers)

The private key is encrypted via DPAPI (Data Protection API). There are many RSA keys in that folder though, but you can still find them by sorting these files by date. If you don't remember the date you got infected, see your screenshot at the crook's webpage or search for the oldest HOW_DECRYPT.TXT file in your system.
I'll update this blog soon!