Cl0p Ransomware Recovery: What's Recoverable

Cl0p (also written Clop) is one of the longer-running groups covered here, first documented in 2019 as a CryptoMix variant distributed by the TA505 threat actor via phishing. It later shifted from phishing toward mass exploitation of vulnerabilities in enterprise file-transfer and networking software to compromise many victims through a single vulnerable product.

Cl0p combines Salsa20, AES and ECDH encryption, appending extensions like .clop or variants of it, with ransom notes typically named ClopReadMe.txt. It specifically targets Windows infrastructure with Active Directory deployed, using SMB and Windows admin shares for lateral movement once inside — meaning domain-joined servers and shared storage are usually squarely in scope.

Cl0p's history of compromising many organizations through a single exploited product means the initial entry point is often already publicly known once an incident is attributed to this group — worth checking against your own exposure. For recovery, its heavy reliance on Active Directory and SMB shares for lateral movement means domain controllers and file shares typically need assessment alongside whatever was directly encrypted, not just the systems where the ransom note appeared.