Malware lab, Emsisoft, released a free decryptor tool on June 4. The tool enables victims to recover files encrypted by Tycoon ransomware attacks without needing to pay the ransom.
Researchers from the BlackBerry’s security unit first discovered the ransomware. They stated in TechCrunch that Tycoon uses a Java file format to make it more difficult to detect before deploying its payload that encrypts the files.
During an interview Brett Called, threat analyst of Emsisoft explained how Tycoon works saying:
“Tycoon is a Java-based, human-operated ransomware that appears to specifically target smaller enterprises and is typically deployed via an attack on RDP. Java-based ransomware is unusual, but certainly not unique. Microsoft warned about another Java-based ransomware strain, PonyFinal, last month.”
On the tool, Callow also clarified some of the limitations of the free tool “Emsisoft Decryptor for RedRum”:
“(…) the tool only works for files encrypted by the original Tycoon variant, not for files encrypted by any subsequent variants. This means it will work for files that have a .RedRum extension, but not for files with .grinch or .thanos extension. Unfortunately, the only way to recover files with those latter extensions is to pay the ransom.”
BlackBerry’s researchers noted that Tycoon ransomware can run on both Windows and Linux computers, employing the same technique of asking for cryptocurrency payments like Bitcoin (BTC).