MALWARE FAMILY
MISTPEN
Internal ID: win.mistpen
1
aliases
Last seen:Mar 17, 2026
Intelligence Profile
According to Mandiant, MISTPEN is a lightweight backdoor written in C whose main functionality is to download and execute Portable Executable (PE) files. The backdoor is a modification of the open-source Notepad++ binhex plugin v2.0.0.1 where the creation of a thread that executes the malicious code has been added to the DllMain function.
Threat Analysis
MISTPEN is a malware family tracked by threat intelligence researchers and catalogued in the Malpedia dataset. It represents a distinct malicious software lineage with identifiable code characteristics, behaviors, and victimology.
External References
Quick Facts
TypeMalware Family
Aliases1
Also Known As
win.mistpen
Research Links
Data sourced from Malpedia, Ransomware.live, RansomLook, and CTIWATCH OSINT collection. Actor attribution is based on available intelligence and may be incomplete.