Gandcrab is a new family of ransomware that was spotted in January; it is the first to emerge after a hiatus during which cryptocurrency mining scripts seemed to have emerged as the next generation of threats.
Bogdan Botezatu, senior e-threat analyst at Bitdefender's labs in Romania, said that Gandcrab spread via malicious advertisements which led to landing pages for the Rig Exploit Kit.
Gandcrab also spread through specially crafted email messages which posed as receipts and had managed to infect about 50,000 Windows computers, he said.
The decryption tool, which has also had contributions from the Romanian Police, the Directorate for Investigating Organised Crime and Terrorism and Europol, is available here.
It will also soon be available on the nomoreransom.org site which hosts decryption tools for numerous other ransomware strains as well.