Sigma rule: FoggyWeb Backdoor DLL Loading

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-97e248f63938, updated 2022-12-09T00:00:00.000Z.

Rule

Title: FoggyWeb Backdoor DLL Loading
Status: test
Level: critical
Author: Florian Roth (Nextron Systems)
Date: 2021-09-27
Modified: 2022-12-09
File: rules-emerging-threats/2021/Malware/FoggyWeb/image_load_malware_foggyweb_nobelium.yml
Commit: ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects DLL hijacking technique used by NOBELIUM in their FoggyWeb backdoor. Which loads a malicious version of the expected "version.dll" dll

Log source

product: windows
category: image_load

Detection

selection:
    ImageLoaded: 'C:\Windows\ADFS\version.dll'
condition: selection

False positives (as the rule lists them)

Unlikely

MITRE ATT&CK ids this rule names

T1587

References

https://www.microsoft.com/security/blog/2021/09/27/foggyweb-targeted-nobelium-malware-leads-to-persistent-backdoor/

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-emerging-threats/2021/Malware/FoggyWeb/image_load_malware_foggyweb_nobelium.yml

Sources and licences

SigmaHQ
"FoggyWeb Backdoor DLL Loading" by Florian Roth (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-emerging-threats/2021/Malware/FoggyWeb/image_load_malware_foggyweb_nobelium.yml.
Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License
Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: FoggyWeb Backdoor DLL Loading",
entity page, dataset version ref-97e248f63938, updated 2022-12-09T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/640dc51c-7713-4faa-8a0e-e7c0d9d4654c (accessed 2026-11-03).
Underlying source: SigmaHQ rule 640dc51c-7713-4faa-8a0e-e7c0d9d4654c, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.