Renamed NirCmd.EXE Execution — Sigma Rule

Rule metadata and linked tags

Author: X__Junior (Nextron Systems). Source status: test; severity: high. Source dates: 2024-03-11 / not supplied.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: a38606f06612030cd96836e9b5626a60002168f22f08879bddf636a6874cf73f

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Renamed NirCmd.EXE Execution
id: 264982dc-dbad-4dce-b707-1e0d3e0f73d9
status: test
description: Detects the execution of a renamed "NirCmd.exe" binary based on the PE metadata fields.
references:
    - https://www.microsoft.com/en-us/security/blog/2024/01/17/new-ttps-observed-in-mint-sandstorm-campaign-targeting-high-profile-individuals-at-universities-and-research-orgs/
    - https://www.nirsoft.net/utils/nircmd.html
author: X__Junior (Nextron Systems)
date: 2024-03-11
tags:
    - attack.execution
    - attack.stealth
    - attack.t1059
    - attack.t1202
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        OriginalFileName: 'NirCmd.exe'
    filter_main_img:
        Image|endswith:
            - '\nircmd.exe'
            - '\nircmdc.exe'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://www.microsoft.com/en-us/security/blog/2024/01/17/new-ttps-observed-in-mint-sandstorm-campaign-targeting-high-profile-individuals-at-universities-and-research-orgs/
• https://www.nirsoft.net/utils/nircmd.html