Sigma rule: Potential Kapeka Decrypted Backdoor Indicator

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-4cce19006846, updated 2024-07-03T00:00:00.000Z.

Rule

Title: Potential Kapeka Decrypted Backdoor Indicator
Status: test
Level: high
Author: Swachchhanda Shrawan Poudel, Nasreddine Bencherchali (Nextron Systems)
Date: 2024-07-03
File: rules-emerging-threats/2024/Malware/kapeka/file_event_win_malware_kapeka_backdoor_indicators.yml
Commit: ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the presence of a file that is decrypted backdoor binary dropped by the Kapeka Dropper, which disguises itself as a hidden file under a folder named "Microsoft" within "CSIDL_COMMON_APPDATA" or "CSIDL_LOCAL_APPDATA", depending on the process privileges.
The file, typically 5-6 characters long with a random combination of consonants and vowels followed by a ".wll" extension to pose as a legitimate file to evade detection.

Log source

product: windows
category: file_event

Detection

selection_generic:
    TargetFilename|contains:
        - ':\ProgramData\'
        - '\AppData\Local\'
    TargetFilename|re: '\\[a-zA-Z]{5,6}\.wll'
selection_specific:
    TargetFilename|endswith:
        - '\win32log.exe'
        - '\crdss.exe'
condition: 1 of selection_*

False positives (as the rule lists them)

Unknown

References

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/2024/Malware/kapeka/file_event_win_malware_kapeka_backdoor_indicators.yml

Sources and licences

SigmaHQ
"Potential Kapeka Decrypted Backdoor Indicator" by Swachchhanda Shrawan Poudel, Nasreddine Bencherchali (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-emerging-threats/2024/Malware/kapeka/file_event_win_malware_kapeka_backdoor_indicators.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: Potential Kapeka Decrypted Backdoor Indicator",
entity page, dataset version ref-4cce19006846, updated 2024-07-03T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/20228d05-dd68-435d-8b4e-e7e64938880c (accessed 2026-11-03).
Underlying source: SigmaHQ rule 20228d05-dd68-435d-8b4e-e7e64938880c, 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.