Sigma Rule Library

Kapeka Backdoor Execution Via RunDLL32.EXE

Detects Kapeka backdoor process execution pattern, where the dropper launch the backdoor binary by calling rundll32 and passing the backdoor's first export ordinal (#1) with a "-d" argument.

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Detection logic

selection_img

- Image|endswith: \rundll32.exe
- OriginalFileName: RUNDLL32.EXE

selection_backdoor_path

CommandLine|contains:
  - :\ProgramData
  - \AppData\Local

selection_backdoor_exec_1

CommandLine|contains|all:
  - .wll
  - "#1"
  - " -d"

selection_backdoor_exec_2

CommandLine|contains: .wll
CommandLine|endswith: "#1"

Condition

selection_img and selection_backdoor_path and 1 of selection_backdoor_exec_*

Raw YAML

title: Kapeka Backdoor Execution Via RunDLL32.EXE
id: e98f741c-6a5b-4c83-bc2a-1f4e58d07b12
status: test
description: |
    Detects Kapeka backdoor process execution pattern, where the dropper launch the backdoor binary by calling rundll32 and passing the backdoor's first export ordinal (#1) with a "-d" argument.
references:
    - https://labs.withsecure.com/publications/kapeka
    - https://app.any.run/tasks/1efb3ed4-cc0f-4690-a0ed-24516809bc72/
author: Swachchhanda Shrawan Poudel, Nasreddine Bencherchali (Nextron Systems)
date: 2024-07-03
tags:
    - attack.stealth
    - attack.t1218.011
    - detection.emerging-threats
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\rundll32.exe'
        - OriginalFileName: 'RUNDLL32.EXE'
    selection_backdoor_path:
        CommandLine|contains:
            - ':\ProgramData'
            - '\AppData\Local'
    selection_backdoor_exec_1:
        CommandLine|contains|all:
            - '.wll'
            - '#1'
            - ' -d'
    selection_backdoor_exec_2:
        # This account for the in the wild variant
        CommandLine|contains: '.wll'
        CommandLine|endswith: '#1'
    condition: selection_img and selection_backdoor_path and 1 of selection_backdoor_exec_*
falsepositives:
    - Unknown
level: high

False positives

  • Unknown

References

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