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IMAPLoader

This is a defensive tool-intelligence page. It is intended for analyst navigation, source review, and hunt planning. It is not a malware-analysis report and does not contain sample code or binaries.

Summary

  • Associated actor(s): Imperial Kitten
  • Tool type(s): .NET downloader / loader
  • Confidence level(s): High
  • Source ID(s): SRC-PWC-YELLOW-LIDERC-2023

Behavior

ActorBehavior Summary
Imperial KittenPwC and related reporting describe IMAPLoader as an Imperial Kitten/Yellow Liderc .NET loader using legitimate or compromised email accounts for IMAP-based C2 after strategic web compromise or lure execution; it identifies target systems and can deploy follow-on payloads.

Hash And IOC Status

ActorStatusReference
Imperial KittenHash not committed; use PwC or vendor IOC appendix/current report for current sample hashes and mail-account indicators.SRC-PWC-YELLOW-LIDERC-2023

Hashes and IOCs on this page are source pointers or representative public indicators. They SHOULD be refreshed from the linked source before operational use and MUST NOT be used alone for actor attribution.

Defensive Hunting Notes

ActorHunting Notes
Imperial KittenHunt non-mail-client IMAP/IMAPS egress, high-frequency mailbox polling, encoded attachment retrieval by unusual processes, and Office/XLL to csc.exe chains after maritime/logistics web compromise.

Handling Notes

ActorHandling Notes
Imperial KittenBehavior must be locally allowlisted for legitimate IMAP applications.

Mapped ATT&CK Techniques For Associated Actor(s)

ActorTechniqueTacticMapping QualitySource
Imperial KittenT1189 Drive-by CompromiseInitial AccessM2SRC-CS-IMPERIAL-KITTEN-2023
Imperial KittenT1071.003 Mail ProtocolsCommand and ControlM3SRC-PWC-YELLOW-LIDERC-2023
Imperial KittenT1059.005 Visual BasicExecutionM2SRC-PWC-YELLOW-LIDERC-2023

These detections are mapped through the associated actor or scenario and are not automatically tool-specific. Promote a tool-specific detection only after the behavior is tied to telemetry and test evidence.

No repository detection is currently mapped to the associated actor(s). Use the hunting notes and source references as backlog input.

These hunts are mapped through the associated actor or scenario and may need narrowing before they are used for this specific tool.

No repository hunt is currently mapped to the associated actor(s). Create a hunt from the behavior and telemetry notes before proposing a production detection.

Source Review

SourcePublisherDateReliabilityTypeLast Reviewed
SRC-PWC-YELLOW-LIDERC-2023PwC2023-10-25AVendor CTI2026-05-14

If a source publishes a large or frequently changing IOC appendix, keep the current IOC list in the source system or TIP and store only the pointer here.