GandCrab Ransomware affiliates are doing their victims a favor by distributing a version of the ransomware that can be decrypted for free. At least one affiliate is continuing to distribute the older 5.1 version that is decryptable, rather than switching to the new 5.2 version, which is no longer decryptable. If you become infected, be sure to check the version number. If it is 5.1 or earlier, then you can use the BitDefender decrypter to get your files back.
Source: https://www.bleepingcomputer.com/news/security/gandcrab-ransomware-affiliates-continue-to-push-decryptable-versions/