Detection rules › Sigma

Wab/Wabmig Unusual Parent Or Child Processes

Status
test
Severity
high
Log source
product windows, category process_creation
Author
Nasreddine Bencherchali (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects unusual parent or children of the wab.exe (Windows Contacts) and Wabmig.exe (Microsoft Address Book Import Tool) processes as seen being used with bumblebee activity

MITRE ATT&CK coverage

TacticTechniques
ExecutionNo specific technique
StealthNo specific technique

Event coverage

Rule body yaml

title: Wab/Wabmig Unusual Parent Or Child Processes
id: 63d1ccc0-2a43-4f4b-9289-361b308991ff
status: test
description: Detects unusual parent or children of the wab.exe (Windows Contacts) and Wabmig.exe (Microsoft Address Book Import Tool) processes as seen being used with bumblebee activity
references:
    - https://thedfirreport.com/2022/08/08/bumblebee-roasts-its-way-to-domain-admin/
    - https://symantec-enterprise-blogs.security.com/blogs/threat-intelligence/bumblebee-loader-cybercrime
    - https://thedfirreport.com/2022/09/26/bumblebee-round-two/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-08-12
modified: 2022-09-27
tags:
    - attack.execution
    - attack.stealth
logsource:
    category: process_creation
    product: windows
detection:
    selection_parent:
        ParentImage|endswith:
            # Add more if known
            - \WmiPrvSE.exe
            - \svchost.exe
            - \dllhost.exe
        Image|endswith:
            - '\wab.exe'
            - '\wabmig.exe' # (Microsoft Address Book Import Tool)
    selection_child:
        # You can add specific suspicious child processes (such as cmd, powershell...) to increase the accuracy
        ParentImage|endswith:
            - '\wab.exe'
            - '\wabmig.exe' # (Microsoft Address Book Import Tool)
    condition: 1 of selection_*
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

1 of selection_*

Stage 1: selection_parent

selection_parent:
    ParentImage|endswith:
        - \WmiPrvSE.exe
        - \svchost.exe
        - \dllhost.exe
    Image|endswith:
        - '\wab.exe'
        - '\wabmig.exe'

Stage 2: selection_child

selection_child:
    ParentImage|endswith:
        - '\wab.exe'
        - '\wabmig.exe'

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
  • \wab.exe corpus 3 (sigma 3)
  • \wabmig.exe corpus 3 (sigma 3)
ParentImageends_with
  • \WmiPrvSE.exe corpus 8 (sigma 8)
  • \dllhost.exe corpus 7 (sigma 7)
  • \svchost.exe corpus 14 (sigma 14)
  • \wab.exe
  • \wabmig.exe