In a statement, the company said the decryption tool would be effective in decrypting files that had been encrypted by the latest versions of Gandcrab.
The company released its first version of the decryption tool in March this year.
Gandcrab spreads via malicious advertisements which lead to landing pages for the Rig Exploit Kit. It can also spread through spam email and affiliated malware campaigns.
Once Gandcrab has done its work, a ransom note, asking for anything between a few hundred and hundreds of thousands of DASH, a new cryptocurrency, is displayed on an infected system.
“The release of this decryption tool is a spectacular breakthrough that highlights the effectiveness of collaboration between security vendors and law enforcement agencies,” a Bitdefender spokesperson said.
“We have spent months on crypto-research and deployed considerable infrastructure to make this possible and help victims regain control of their digital lives at no cost.”
The spokesperson said the updated tool released could decrypt data encrypted by versions 1, 4 and 5 of GandCrab, and also all versions of the ransomware for a limited set of victims in Syria.
GandCrab has been very active since January, operating on an affiliate model with its developers making the malware available as a service to interested parties, in return for a share of the profits.