Sigma rule: Qakbot Regsvr32 Calc Pattern

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-d59e904cee35, updated 2024-03-05T00:00:00.000Z.

Rule

Title
Qakbot Regsvr32 Calc Pattern
Status
test
Level
high
Author
Nasreddine Bencherchali (Nextron Systems)
Date
2023-05-26
Modified
2024-03-05
File
rules-emerging-threats/2023/Malware/Qakbot/proc_creation_win_malware_qakbot_regsvr32_calc_pattern.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects a specific command line of "regsvr32" where the "calc" keyword is used in conjunction with the "/s" flag. This behavior is often seen used by Qakbot

Log source

product
windows
category
process_creation

Detection

selection:
    Image|endswith: '\regsvr32.exe'
    CommandLine|contains|windash: ' -s'
    CommandLine|endswith: ' calc'
condition: selection

False positives (as the rule lists them)

  • Unlikely

Tags

  • attack.execution
  • detection.emerging-threats
  • attack.stealth

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/2023/Malware/Qakbot/proc_creation_win_malware_qakbot_regsvr32_calc_pattern.yml

Sources and licences

  • SigmaHQ

    "Qakbot Regsvr32 Calc Pattern" by Nasreddine Bencherchali (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-emerging-threats/2023/Malware/Qakbot/proc_creation_win_malware_qakbot_regsvr32_calc_pattern.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: Qakbot Regsvr32 Calc Pattern",
entity page, dataset version ref-d59e904cee35, updated 2024-03-05T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/0033cf83-fb87-446d-9cac-43d63ad4d5a9 (accessed 2026-11-03).
Underlying source: SigmaHQ rule 0033cf83-fb87-446d-9cac-43d63ad4d5a9, 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.