Cybersecurity firm Profero has discovered that the RansomExx gang does not correctly lock Linux files during encryption, leading to potentially corrupted files.
In a new report by Profero, Senior Incident Responder Brenton Morris says the RansomEXX decryptor was failing on various files encrypted by the threat actor’s Linux Vmware ESXI encryptor for one the victims who paid the ransom.
After reverse-engineering the RansomExx Linux encryptor, Profero discovered that the problematic decryption was caused by Linux files not being adequately locked while they were encrypted.
Without the file being locked, if the ransomware attempted to encrypt a Linux file simultaneously as another process wrote to it, the encrypted file would contain both encrypted data and unencrypted data appended after it, as shown below.