Threat Group Cards: A Threat Actor Encyclopedia Archived: 2026-04-05 17:58:53 UTC Home > List all groups > List all tools > List all groups using tool Geppei Tool: Geppei Names Geppei Category Malware Type Dropper Description (Symantec) The first malicious activity Symantec researchers saw on victim machines was the presence of a previously undocumented dropper (Trojan.Geppei). It uses PyInstaller, which converts Python script to an executable file. Geppei reads commands from a legitimate IIS log. IIS logs are meant to record data from IIS, such as web pages and apps. The attackers can send commands to a compromised web server by disguising them as web access requests. IIS logs them as normal but Trojan.Geppei can read them as commands. The commands read by Geppei contain malicious encoded .ashx files. These files are saved to an arbitrary folder determined by the command parameter and they run as backdoors. Information Last change to this tool card: 18 November 2022 Download this tool card in JSON format All groups using tool Geppei Changed Name Country Observed APT groups   APT 29, Cozy Bear, The Dukes 2008-Feb 2025 1 group listed (1 APT, 0 other, 0 unknown) https://apt.etda.or.th/cgi-bin/listgroups.cgi?u=46e2b498-934d-47a5-9dab-9d4cdda34c97 Page 1 of 2 Source: https://apt.etda.or.th/cgi-bin/listgroups.cgi?u=46e2b498-934d-47a5-9dab-9d4cdda34c97 https://apt.etda.or.th/cgi-bin/listgroups.cgi?u=46e2b498-934d-47a5-9dab-9d4cdda34c97 Page 2 of 2 APT groups APT 29, Cozy Bear, The Dukes 2008-Feb 2025 1 group listed (1 APT, 0 other, 0 unknown) Page 1 of 2