WannaCry Ransomware Decryption Tool ReleasedMay 19, 2017 – 5:25 AM
If your PC has been infected by WannaCry – the ransomware that wreaked havoc across the world last Friday – you might be lucky to get your locked files back without paying the ransom of $300 to the cyber criminals.
Adrien Guinet, a French security researcher from Quarkslab, has discovered a way to retrieve the secret encryption keys used by the WannaCry ransomware for free, which works on Windows XP, Windows 7, Windows Vista, Windows Server 2003 and 2008 operating systems.
The WannaCry’s encryption scheme works by generating a pair of keys on the victim’s computer that rely on prime numbers, a “public” key and a “private” key for encrypting and decrypting the system’s files respectively.
To prevent the victim from accessing the private key and decrypting locked files himself, WannaCry erases the key from the system, leaving no choice for the victims to retrieve the decryption key except paying the ransom to the attacker.
But here’s the kicker: WannaCry “does not erase the prime numbers from memory before freeing the associated memory,” says Guinet.
Based on this finding, Guinet released a WannaCry ransomware decryption tool, named WannaKey, that basically tries to retrieve the two prime numbers, used in the formula to generate encryption keys from memory.