Sigma rule: Ursnif Malware C2 URL Pattern

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-92093914349a, updated 2021-08-09T00:00:00.000Z.

Rule

Title
Ursnif Malware C2 URL Pattern
Status
stable
Level
critical
Author
Thomas Patzke
Date
2019-12-19
Modified
2021-08-09
File
rules-emerging-threats/2019/Malware/Ursnif/proxy_malware_ursnif_c2_url.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects Ursnif C2 traffic.

Log source

category
proxy

Detection

b64encoding:
    c-uri|contains:
        - '_2f'
        - '_2b'
urlpatterns:
    c-uri|contains|all:
        - '.avi'
        - '/images/'
condition: b64encoding and urlpatterns

False positives (as the rule lists them)

  • Unknown

Tags

  • attack.initial-access
  • attack.t1566.001
  • attack.execution
  • attack.t1204.002
  • attack.command-and-control
  • attack.t1071.001
  • detection.emerging-threats

MITRE ATT&CK ids this rule names

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/2019/Malware/Ursnif/proxy_malware_ursnif_c2_url.yml

Sources and licences

  • SigmaHQ

    "Ursnif Malware C2 URL Pattern" by Thomas Patzke (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-emerging-threats/2019/Malware/Ursnif/proxy_malware_ursnif_c2_url.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: Ursnif Malware C2 URL Pattern",
entity page, dataset version ref-92093914349a, updated 2021-08-09T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/932ac737-33ca-4afd-9869-0d48b391fcc9 (accessed 2026-11-03).
Underlying source: SigmaHQ rule 932ac737-33ca-4afd-9869-0d48b391fcc9, 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.