Sigma rule: CVE-2023-38331 Exploitation Attempt - Suspicious Double Extension File

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-684970ea87cd, updated 2023-08-30T00:00:00.000Z.

Rule

Title
CVE-2023-38331 Exploitation Attempt - Suspicious Double Extension File
Status
test
Level
high
Author
Nasreddine Bencherchali (Nextron Systems)
Date
2023-08-30
File
rules-emerging-threats/2023/Exploits/CVE-2023-38831/file_event_win_exploit_cve_2023_38331_winrar_susp_double_ext.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the creation of a file with a double extension and a space by WinRAR. This could be a sign of exploitation of CVE-2023-38331

Log source

product
windows
category
file_event

Detection

selection:
    Image|endswith: '\WinRAR.exe'
    TargetFilename|contains: '\AppData\Local\Temp\Rar$'
    TargetFilename|re: '\.[a-zA-Z0-9]{1,4} \.'
condition: selection

False positives (as the rule lists them)

  • Unknown

Tags

  • attack.execution
  • cve.2023-38331
  • detection.emerging-threats

CVEs 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-emerging-threats/2023/Exploits/CVE-2023-38831/file_event_win_exploit_cve_2023_38331_winrar_susp_double_ext.yml

Sources and licences

  • SigmaHQ

    "CVE-2023-38331 Exploitation Attempt - Suspicious Double Extension File" by Nasreddine Bencherchali (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-emerging-threats/2023/Exploits/CVE-2023-38831/file_event_win_exploit_cve_2023_38331_winrar_susp_double_ext.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: CVE-2023-38331 Exploitation Attempt - Suspicious Double Extension File",
entity page, dataset version ref-684970ea87cd, updated 2023-08-30T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/e4556676-fc5c-4e95-8c39-5ef27791541f (accessed 2026-11-03).
Underlying source: SigmaHQ rule e4556676-fc5c-4e95-8c39-5ef27791541f, 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.