Sigma rule: Suspicious Curl Change User Agents - Linux

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-3c0c3d29cca1, updated 2022-09-15T00:00:00.000Z.

Rule

Title
Suspicious Curl Change User Agents - Linux
Status
test
Level
medium
Author
Nasreddine Bencherchali (Nextron Systems)
Date
2022-09-15
File
rules/linux/process_creation/proc_creation_lnx_susp_curl_useragent.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects a suspicious curl process start on linux with set useragent options

Log source

product
linux
category
process_creation

Detection

selection:
    Image|endswith: '/curl'
    CommandLine|contains:
        - ' -A '
        - ' --user-agent '
condition: selection

False positives (as the rule lists them)

  • Scripts created by developers and admins
  • Administrative activity

Tags

  • attack.command-and-control
  • attack.t1071.001

MITRE ATT&CK ids this rule names

Related rules

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/linux/process_creation/proc_creation_lnx_susp_curl_useragent.yml

Sources and licences

  • SigmaHQ

    "Suspicious Curl Change User Agents - Linux" by Nasreddine Bencherchali (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/linux/process_creation/proc_creation_lnx_susp_curl_useragent.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: Suspicious Curl Change User Agents - Linux",
entity page, dataset version ref-3c0c3d29cca1, updated 2022-09-15T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/b86d356d-6093-443d-971c-9b07db583c68 (accessed 2026-11-03).
Underlying source: SigmaHQ rule b86d356d-6093-443d-971c-9b07db583c68, 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.