Detection rules › Sigma

Renamed NirCmd.EXE Execution

Status
test
Severity
high
Log source
product windows, category process_creation
Author
X__Junior (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects the execution of a renamed "NirCmd.exe" binary based on the PE metadata fields.

MITRE ATT&CK coverage

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation

Rule body yaml

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

Stages and Predicates

Stage 0: condition

selection and not 1 of filter_main_*

Stage 1: selection

selection:
    OriginalFileName: 'NirCmd.exe'

Stage 2: not filter_main_img

filter_main_img:
    Image|endswith:
        - '\nircmd.exe'
        - '\nircmdc.exe'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

FieldKindExcluded values
Imageends_with\nircmd.exe
Imageends_with\nircmdc.exe

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
OriginalFileNameeq
  • NirCmd.exe corpus 2 (sigma 2)