Security Tools Keyword Lookup Via Findstr.EXE — Sigma Rule

Rule metadata and linked tags

Author: Nasreddine Bencherchali (Nextron Systems), frack113. Source status: test; severity: medium. Source dates: 2023-10-20 / 2023-11-14.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 30e29aa6bbab1d6335f15757e5a13620ca3d70ce2b3e3c8cf42ce28f3b3c6d59

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 Tools Keyword Lookup Via Findstr.EXE
id: 4fe074b4-b833-4081-8f24-7dcfeca72b42
related:
    - id: fe63010f-8823-4864-a96b-a7b4a0f7b929
      type: derived
status: test
description: |
    Detects execution of "findstr" to search for common names of security tools. Attackers often pipe the results of recon commands such as "tasklist" or "whoami" to "findstr" in order to filter out the results.
    This detection focuses on the keywords that the attacker might use as a filter.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/987e3ca988ae3cff4b9f6e388c139c05bf44bbb8/atomics/T1518.001/T1518.001.md#atomic-test-1---security-software-discovery
    - https://www.microsoft.com/en-us/security/blog/2023/10/18/multiple-north-korean-threat-actors-exploiting-the-teamcity-cve-2023-42793-vulnerability/
    - https://www.hhs.gov/sites/default/files/manage-engine-vulnerability-sector-alert-tlpclear.pdf
author: Nasreddine Bencherchali (Nextron Systems), frack113
date: 2023-10-20
modified: 2023-11-14
tags:
    - attack.discovery
    - attack.t1518.001
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith:
              - '\find.exe'
              - '\findstr.exe'
        - OriginalFileName:
              - 'FIND.EXE'
              - 'FINDSTR.EXE'
    selection_cli:
        CommandLine|endswith:
            # Note: Add additional keywords to increase and enhance coverage
            # Note:
            #   We use the double quote variation because in cases of where the command is executed through cmd for example:
            #       cmd /c "tasklist | findstr virus"
            #   Logging utilties such as Sysmon would capture the end quote as part of findstr execution
            - ' avira'
            - ' avira"'
            - ' cb'
            - ' cb"'
            - ' cylance'
            - ' cylance"'
            - ' defender'
            - ' defender"'
            - ' kaspersky'
            - ' kaspersky"'
            - ' kes'
            - ' kes"'
            - ' mc'
            - ' mc"'
            - ' sec'
            - ' sec"'
            - ' sentinel'
            - ' sentinel"'
            - ' symantec'
            - ' symantec"'
            - ' virus'
            - ' virus"'
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium
regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_findstr_security_keyword_lookup/info.yml
simulation:
    - type: atomic-red-team
      name: Security Software Discovery
      technique: T1518.001
      atomic_guid: f92a380f-ced9-491f-b338-95a991418ce2

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://github.com/redcanaryco/atomic-red-team/blob/987e3ca988ae3cff4b9f6e388c139c05bf44bbb8/atomics/T1518.001/T1518.001.md#atomic-test-1---security-software-discovery
• https://www.microsoft.com/en-us/security/blog/2023/10/18/multiple-north-korean-threat-actors-exploiting-the-teamcity-cve-2023-42793-vulnerability/
• https://www.hhs.gov/sites/default/files/manage-engine-vulnerability-sector-alert-tlpclear.pdf