Mstsc.EXE Execution From Uncommon Parent

SIGMA detection rule by Nasreddine Bencherchali (Nextron Systems) · NOASSERTION

Detects potential RDP connection via Mstsc using a local ".rdp" file located in suspicious locations.

title: Mstsc.EXE Execution From Uncommon Parent
id: ff3b6b39-e765-42f9-bb2c-ea6761e0e0f6
status: test
description: Detects potential RDP connection via Mstsc using a local ".rdp" file located in suspicious locations.
references:
    - https://www.blackhillsinfosec.com/rogue-rdp-revisiting-initial-access-methods/
    - https://web.archive.org/web/20230726144748/https://blog.thickmints.dev/mintsights/detecting-rogue-rdp/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-04-18
tags:
    - attack.lateral-movement
logsource:
    category: process_creation
    product: windows
detection:
    selection_parent:
        ParentImage|endswith:
            # Covers potential downloads/clicks from browsers
            - '\brave.exe'
            - '\CCleanerBrowser.exe'
            - '\chrome.exe'
            - '\chromium.exe'
            - '\firefox.exe'
            - '\iexplore.exe'
            - '\microsoftedge.exe'
            - '\msedge.exe'
            - '\opera.exe'
            - '\vivaldi.exe'
            - '\whale.exe'
            # Covers potential downloads/clicks from email clients
            - '\outlook.exe'
    selection_img:
        - Image|endswith: '\mstsc.exe'
        - OriginalFileName: 'mstsc.exe'
    condition: all of selection_*
falsepositives:
    - Unlikely
level: high

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

1cdb54f1-081f-46df-aaab-1603d4e6f292

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

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Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

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[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

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