STOP
Intelligence Profile
STOP Djvu Ransomware it is a ransomware which encrypts user data through AES-256 and adds one of the dozen available extensions as marker to the encrypted file's name. It is not used to encrypt the entire file but only the first 5 MB. In its original version it was able to run offline and, in that case, it used a hard-coded key which could be extracted to decrypt files.
Threat Analysis
STOP is a high-sophistication threat actor of undetermined national origin, engaged in cyber operations with a primary motivation of financial.
Financially motivated threat actors like STOP prioritize monetary gain through methods such as ransomware deployment, banking trojans, cryptocurrency theft, BEC scams, or credential harvesting for resale on underground markets.
With high sophistication, STOP is capable of targeted intrusions using adapted commodity tools alongside custom implants, maintaining operational security and evading standard detection mechanisms.