Blackmailing Trojan encrypts hard-drive
Kaspersky Lab asks for help cracking it

By Nick Farrell: Wednesday, 11 June 2008, 8:06 AM


 KASPERSKY Lab has asked the world, plus dog, to help it crack the key to a Trojan that encrypts your hard drive and then demands cash for the key.

Gpcode has been used in isolated "ransomware" attacks for the last two years. The latest version encrypts all .bak, .doc, .jpg and .pdf and deletes the originals. It then erases itself after leaving a message about where to buy a decryption tool.

Kaspersky said that the files the malware encoded cannot be decrypted because it uses a very strong, 1024-bit key.

The insecurity outfit estimates it would take around 15 million modern computers, running for about a year, to crack such a key.

The company has broken Gpcode's encryption keys in the past, but that was only because the malware's maker had made mistakes implementing the encryption algorithm. µ