Potential Suspicious Execution From GUID Like Folder Names

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

Detects potential suspicious execution of a GUID like folder name located in a suspicious location such as %TEMP% as seen being used in IcedID attacks. Use this rule to hunt for potentially suspicious activity stemming from uncommon folders.

title: Potential Suspicious Execution From GUID Like Folder Names
id: 90b63c33-2b97-4631-a011-ceb0f47b77c3
status: test
description: |
    Detects potential suspicious execution of a GUID like folder name located in a suspicious location such as %TEMP% as seen being used in IcedID attacks.
    Use this rule to hunt for potentially suspicious activity stemming from uncommon folders.
references:
    - https://twitter.com/Kostastsale/status/1565257924204986369
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-09-01
modified: 2023-03-02
tags:
    - attack.stealth
    - attack.t1027
    - detection.threat-hunting
logsource:
    category: process_creation
    product: windows
detection:
    # Uncomment this section and remove the filter if you want the rule to be more specific to processes
    # selection_img:
    #     Image|endswith:
    #         - '\rundll32.exe'
    selection_folder:
        CommandLine|contains:
            # Add more suspicious or unexpected paths
            - '\AppData\Roaming\'
            - '\AppData\Local\Temp\' # This could generate some FP with some installers creating folders with GUID
    selection_guid:
        CommandLine|contains|all:
            - '\{'
            - '}\'
    filter_main_image_guid:
        Image|contains|all:
            - '\{'
            - '}\'
    filter_main_null:
        Image: null
    filter_main_driver_inst:  # DrvInst.exe "4" "0" "C:\Users\venom\AppData\Local\Temp\{a0753cc2-fcea-4d49-a787-2290b564b06f}\nvvhci.inf" "9" "43a2fa8e7" "00000000000001C0" "WinSta0\Default" "00000000000001C4" "208" "c:\program files\nvidia corporation\installer2\nvvhci.{eb7b4460-7ec9-42d6-b73f-d487d4550526}"
        Image: 'C:\Windows\System32\drvinst.exe'
    filter_main_msiexec:
        Image:
            - 'C:\Windows\System32\msiexec.exe'
            - 'C:\Windows\SysWOW64\msiexec.exe'
    condition: all of selection_* and not 1 of filter*
falsepositives:
    - Installers are sometimes known for creating temporary folders with GUID like names. Add appropriate filters accordingly
level: low

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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.

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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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