Hello,
I have a client which is infected with ransom virus (sos@anointernet.com).
What it does:
1. Append XXXXXXXXX-sos@anointernet.com to filenames
2. Modify exactly the first 30 000 bits of the file (looks as encryption at first look)
3. Append 4 bits at the end of the file.
4. Ask for money for decryption
I've attached a screenshot on the precise end of the encryption and start of real document.
Lucky the document has a predictable output of auto increment numbers.
There are occurring 03 00 00 <3 digit number> 03 00 00
Is there some technique I could apply to narrow down what type of encryption that is ?
Obviously encrypts same bits differently.
I was thinking of frequency analysis but I'm wondering how to apply it to binary file.
It is some form of CryptoLocker probably, but is there a way to confirm RSA-2048 bit encryption ?
Any thoughts are welcome