Suspicious Calc DLL Load

SIGMA detection rule by Micah Babinski · GPL-3.0

Detects Windows 7 calc.exe loading DLLs from suspicious or abnormal file paths.

title: Suspicious Calc DLL Load
id: b47b9cc3-6f9a-4a58-a669-5e5e126514b1
status: experimental
description: Detects Windows 7 calc.exe loading DLLs from suspicious or abnormal file paths.
references:
    - https://www.trellix.com/en-us/about/newsroom/stories/research/demystifying-qbot-malware.html
author: Micah Babinski
date: 2022/11/19
tags:
    - attack.persistence
    - attack.t1574
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\calc.exe'
    filter:
        ImageLoaded|startswith:
            - 'C:\Windows\System32'
            - 'C:\Windows\SysWOW64'
    condition: selection and not filter
falsepositives:
    - Unknown
level: high

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

8744e5d4-ad41-4a38-964b-e4891a815e2a

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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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