Security Software Discovery Via Powershell Script — Sigma Rule

Rule metadata and linked tags

Author: frack113, Anish Bogati, Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: medium. Source dates: 2021-12-16 / 2023-10-24.

{
  "product": "windows",
  "category": "ps_script",
  "definition": "Requirements: Script Block Logging must be enabled"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 2bd6e3fc916e3f09f9192796b9e6ba1f06ab714cd2ebe2bdbc19b44546e8ab62

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: Security Software Discovery Via Powershell Script
id: 904e8e61-8edf-4350-b59c-b905fc8e810c
status: test
description: |
    Detects calls to "get-process" where the output is piped to a "where-object" filter to search for security solution processes.
    Adversaries may attempt to get a listing of security software, configurations, defensive tools, and sensors that are installed on a system or in a cloud environment. This may include things such as firewall rules and anti-virus
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1518.001/T1518.001.md#atomic-test-2---security-software-discovery---powershell
author: frack113, Anish Bogati, Nasreddine Bencherchali (Nextron Systems)
date: 2021-12-16
modified: 2023-10-24
tags:
    - attack.discovery
    - attack.t1518.001
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection_cmdlet:
        ScriptBlockText|contains:
            - 'get-process | \?'
            - 'get-process | where'
            - 'gps | \?'
            - 'gps | where'
    selection_field:
        ScriptBlockText|contains:
            - 'Company -like'
            - 'Description -like'
            - 'Name -like'
            - 'Path -like'
            - 'Product -like'
    selection_keywords:
        ScriptBlockText|contains:
            # Note: These strings are using wildcard assuming the search is using the "-like" operator.
            #       You can add specific variant with the actual process names to increase coverage
            - '\*avira\*'
            - '\*carbonblack\*'
            - '\*cylance\*'
            - '\*defender\*'
            - '\*kaspersky\*'
            - '\*malware\*'
            - '\*sentinel\*'
            - '\*symantec\*'
            - '\*virus\*'
    condition: all of selection_*
falsepositives:
    - False positives might occur due to the nature of the ScriptBlock being ingested as a big blob. Initial tuning is required.
    - As the "selection_cmdlet" is common in scripts the matching engine might slow down the search. Change into regex or a more accurate string to avoid heavy resource consumption if experienced
level: medium

Original YAML and metadata in JSON

False positives

• False positives might occur due to the nature of the ScriptBlock being ingested as a big blob. Initial tuning is required.
• As the "selection_cmdlet" is common in scripts the matching engine might slow down the search. Change into regex or a more accurate string to avoid heavy resource consumption if experienced

Source references

• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1518.001/T1518.001.md#atomic-test-2---security-software-discovery---powershell