The authors of the TeslaCrypt ransomware have handed over their master keys in what appears to be a decision to kill off the net menace.

An Eset researcher noticed the gradual decline of TeslaCrypt and, posing as a victim, asked the malware authors for a key.

The authors surprisingly offered a free master key and the security wonk quickly produced a free universal decryption tool.

It means victims of two of the worst ransomware tools can decrypt their files for free, with Kaspersky white hats producing a decryption tool yesterday for the Cryptxxx malware.

TeslaCrypt was used in massive malvertising attacks against visitors to high profile sites.

Decryption tools are released periodically as white hats find vulnerabilities, often in a ransomware's implementation of an encryption scheme.

This has gradually given way to usage of Cryptxxx as the payload of choice for infected computers.

The TeslaCrypt decrypter.

It is all-but-unheard-of for ransomware authors to release a master key capable of decrypting all infected files.

Organisations should keep backups of important data in offline sources and have a response plan in place should ransomware hit their networks. ®