Wab Execution From Non Default Location

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

Detects execution of wab.exe (Windows Contacts) and Wabmig.exe (Microsoft Address Book Import Tool) from non default locations as seen with bumblebee activity

MITRE ATT&CK coverage

Tactic	Techniques
Execution	No specific technique
Stealth	No specific technique

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation
Security-Auditing	Event ID 4688: A new process has been created.

Rule body

title: Wab Execution From Non Default Location
id: 395907ee-96e5-4666-af2e-2ca91688e151
status: test
description: Detects execution of wab.exe (Windows Contacts) and Wabmig.exe (Microsoft Address Book Import Tool) from non default locations as seen 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:
        Image|endswith:
            - '\wab.exe'
            - '\wabmig.exe'
    filter:
        Image|startswith:
            - 'C:\Windows\WinSxS\'
            - 'C:\Program Files\Windows Mail\'
            - 'C:\Program Files (x86)\Windows Mail\'
    condition: selection and not filter
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: `condition`

selection and not filter

Stage 1: `selection`

selection:
    Image|endswith:
        - '\wab.exe'
        - '\wabmig.exe'

Stage 2: `not filter`

filter:
    Image|startswith:
        - 'C:\Windows\WinSxS\'
        - 'C:\Program Files\Windows Mail\'
        - 'C:\Program Files (x86)\Windows Mail\'

Exclusions

The rule actively suppresses these predicates.

Field	Kind	Excluded values	Search
`Image`	starts_with	`C:\Program Files (x86)\Windows Mail\`	`excludes:Image` `field:"Image" value:"C:\Program Files (x86)\Windows Mail\"`
`Image`	starts_with	`C:\Program Files\Windows Mail\`	`excludes:Image` `field:"Image" value:"C:\Program Files\Windows Mail\"`
`Image`	starts_with	`C:\Windows\WinSxS\`	`excludes:Image` `field:"Image" value:"C:\Windows\WinSxS\"`

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`Image`	ends_with	`\wab.exe` corpus 2 (sigma 2) `\wabmig.exe` corpus 2 (sigma 2)	`field:"Image" kind:ends_with`