Sigma rule: Potential Atlassian Confluence CVE-2021-26084 Exploitation Attempt

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-5cc7f10a2862, updated 2023-02-13T00:00:00.000Z.

Rule

Title
Potential Atlassian Confluence CVE-2021-26084 Exploitation Attempt
Status
test
Level
high
Author
Bhabesh Raj
Date
2021-09-08
Modified
2023-02-13
File
rules-emerging-threats/2021/Exploits/CVE-2021-26084/proc_creation_win_exploit_cve_2021_26084_atlassian_confluence.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects spawning of suspicious child processes by Atlassian Confluence server which may indicate successful exploitation of CVE-2021-26084

Log source

product
windows
category
process_creation

Detection

selection:
    # Monitor suspicious child processes spawned by Confluence
    ParentImage|endswith: '\Atlassian\Confluence\jre\bin\java.exe'
    CommandLine|contains:
        - 'certutil'
        - 'cmd /c'
        - 'cmd /k'
        - 'cscript'
        - 'curl'
        - 'ipconfig'
        - 'powershell'
        - 'pwsh'
        - 'regsvr32'
        - 'rundll32'
        - 'whoami'
        - 'wscript'
condition: selection

False positives (as the rule lists them)

  • Unknown

Tags

  • attack.initial-access
  • attack.execution
  • attack.t1190
  • attack.t1059
  • cve.2021-26084
  • detection.emerging-threats

CVEs this rule names

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/2021/Exploits/CVE-2021-26084/proc_creation_win_exploit_cve_2021_26084_atlassian_confluence.yml

Sources and licences

  • SigmaHQ

    "Potential Atlassian Confluence CVE-2021-26084 Exploitation Attempt" by Bhabesh Raj (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-emerging-threats/2021/Exploits/CVE-2021-26084/proc_creation_win_exploit_cve_2021_26084_atlassian_confluence.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 Atlassian Confluence CVE-2021-26084 Exploitation Attempt",
entity page, dataset version ref-5cc7f10a2862, updated 2023-02-13T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/245f92e3-c4da-45f1-9070-bc552e06db11 (accessed 2026-11-03).
Underlying source: SigmaHQ rule 245f92e3-c4da-45f1-9070-bc552e06db11, 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.