APT / THREAT GROUP

PRIVATELOG

aliases

Last seen:Mar 17, 2026

Intelligence Profile

Malware that abuses the Common Log File System (CLFS) to store/hide a second stage payload via registry transaction files.

Threat Analysis

PRIVATELOG is a known-sophistication threat actor of undetermined national origin, engaged in cyber operations with a primary motivation of unknown activity patterns.

External References

→https://twitter.com/ESETresearch/status/1433819369784610828

→https://www.cybereason.com/blog/operation-cuckoobees-a-winnti-malware-arsenal-deep-dive

→https://www.cybereason.com/blog/operation-cuckoobees-deep-dive-into-stealthy-winnti-techniques

→https://www.fireeye.com/blog/threat-research/2021/09/unknown-actor-using-clfs-log-files-for-stealth.html

Quick Facts

TypeAPT / Threat Group

Aliases2

Also Known As

PRIVATELOGwin.privatelog

External Intelligence

Malpedia: win.privatelog

Research Links

MITRE ATT&CK VirusTotal Google (news) Twitter/X search

Data sourced from Malpedia, Ransomware.live, RansomLook, and CTIWATCH OSINT collection. Actor attribution is based on available intelligence and may be incomplete.

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