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Suspicious GrpConv Execution — Sigma Rule

Sigma rule f14e169e-9978-4c69-acb3-1cff8200bc36. Suspicious GrpConv Execution — Sigma Rule. Detects the suspicious execution of a utility to convert Windows 3.x .grp files or for persistence purposes by malicious software or actors

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems). Source status: test; severity: high. Source dates: 2022-05-19 / not supplied.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: ac388faa2bbd6a851693ae98811b2faf0d90319aaa9791adc921b8d0cb5803c7

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: Suspicious GrpConv Execution
id: f14e169e-9978-4c69-acb3-1cff8200bc36
status: test
description: Detects the suspicious execution of a utility to convert Windows 3.x .grp files or for persistence purposes by malicious software or actors
references:
    - https://twitter.com/0gtweet/status/1526833181831200770
author: Florian Roth (Nextron Systems)
date: 2022-05-19
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1547
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        CommandLine|contains:
            - 'grpconv.exe -o'
            - 'grpconv -o'
    condition: selection
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

  • Unknown

Source references

Connected ecosystem references

Exact source-tagged techniques

Telemetry review

Read the original logsource above, then inspect the linked detection workspaces for technique-level sensor context. No per-rule telemetry equivalence is inferred.

Pinned research references. No browser attack runner, live simulation result or validated detector is asserted. Source mappings and validation limits are preserved. ATT&CK / Atomic provenance · Detection provenance.