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Djvu is a Windows ransomware family first observed in late 2018 and widely regarded as a STOP variant or close successor. It became one of the most prevalent commodity ransomware strains affecting consumers and small organizations, with infections strongly associated with pirated software, software cracks, and adware-bundled installers. It has also appeared as a payload delivered by malware distribution services such as PrivateLoader, sometimes alongside other crimeware including stealers and loaders.
Once executed, Djvu installs multiple components in user-accessible application data locations and launches auxiliary modules that weaken host defenses and support encryption. Documented behavior includes disabling or degrading Microsoft Defender protections, modifying the HOSTS file to block access to security and remediation resources, contacting command-and-control infrastructure to obtain encryption material, and displaying a fake Windows Update screen while files are being encrypted. The malware encrypts a broad range of files on the local system and drops ransom notes in affected directories. Operators typically demand payment for a private key and decryptor, offer to decrypt one file for free, and use time-limited discount language to pressure victims.
Djvu also establishes persistence so encryption activity can resume or newly created files can be encrypted after reboot. Reported persistence mechanisms include scheduled task creation, and some variants have been observed using autorun-style startup mechanisms. The family has been notable for high infection volume and frequent variant churn, including changes to appended encrypted-file extensions and operator contact details.
The malware is primarily associated with financially motivated cybercrime rather than a named state actor. Its distribution through cracked software ecosystems and pay-per-install loader services has made it a recurring component of broader commodity malware campaigns. Victims have included large numbers of individual users worldwide, especially those seeking unauthorized software downloads.
Mallory pivots from this family to the IOCs, detections, and named campaigns that touch your stack, and pages you when something new lands.
10 distinct techniques documented for this family, organized by ATT&CK tactic.
During this process, the ransomware will generate a unique ID for the machine... and connect to it's Command & Control server at the url http://morgem[.]ru/test/get.php?pid=[machine_id]. The server would then reply back with the encryption key that should be used to encrypt a victim's files.
6 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Ransomware family observed as a payload delivered by PrivateLoader.
Ransomware family referenced as a source of leaked code/builders for derivative variants.
Djvu is identified as one of the payloads delivered through the observed tasking. The sample includes ransom-note strings and file-encryption behavior.
Referenced as a ransomware family distributed by the loader infrastructure.
Match every observed IP, domain, and hash against your live telemetry.
Named campaigns wielding this family, with evidence pinned to each claim.
CVEs this family uses for access and lateral movement.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Every documented technique, ranked by evidence weight.
Reddit, Mastodon, and CTI community discussion around this family.