Detection rules › Sigma

Kapeka Backdoor Loaded Via Rundll32.EXE

Status
test
Severity
high
Log source
product windows, category image_load
Author
Swachchhanda Shrawan Poudel
Source
github.com/SigmaHQ/sigma

Detects the Kapeka Backdoor binary being loaded by rundll32.exe. The Kapeka loader drops a backdoor, which is a DLL with the '.wll' extension masquerading as a Microsoft Word Add-In.

MITRE ATT&CK coverage

Event coverage

ProviderEventTitle
SysmonEvent ID 7Image loaded

Rule body yaml

title: Kapeka Backdoor Loaded Via Rundll32.EXE
id: a7e6b1f9-8d2c-4f1e-9a7d-63e4c8a2bf4c
status: test
description: |
    Detects the Kapeka Backdoor binary being loaded by rundll32.exe.
    The Kapeka loader drops a backdoor, which is a DLL with the '.wll' extension masquerading as a Microsoft Word Add-In.
references:
    - https://labs.withsecure.com/publications/kapeka
    - https://app.any.run/tasks/1efb3ed4-cc0f-4690-a0ed-24516809bc72/
author: Swachchhanda Shrawan Poudel
date: 2024-07-03
tags:
    - attack.execution
    - attack.stealth
    - attack.t1204.002
    - attack.t1218.011
    - detection.emerging-threats
logsource:
    category: image_load
    product: windows
detection:
    selection:
        Image|endswith: '\rundll32.exe'
        ImageLoaded|contains:
            - ':\ProgramData'
            - '\AppData\Local\'
        ImageLoaded|re: '[a-zA-Z]{5,6}\.wll'
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    Image|endswith: '\rundll32.exe'
    ImageLoaded|contains:
        - ':\ProgramData'
        - '\AppData\Local\'
    ImageLoaded|re: '[a-zA-Z]{5,6}\.wll'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Imageends_with
  • \rundll32.exe corpus 95 (sigma 95)
ImageLoadedmatch
  • :\ProgramData
  • \AppData\Local\
ImageLoadedregex_match
  • [a-zA-Z]{5,6}.wll