Detection rules › Sigma

Potential CVE-2021-44228 Exploitation Attempt - VMware Horizon

Status
test
Severity
high
Log source
product windows, category process_creation
Author
@kostastsale
Source
github.com/SigmaHQ/sigma

Detects potential initial exploitation attempts against VMware Horizon deployments running a vulnerable versions of Log4j.

MITRE ATT&CK coverage

TacticTechniques
Initial AccessT1190 Exploit Public-Facing Application

Event coverage

Rule body yaml

title: Potential CVE-2021-44228 Exploitation Attempt - VMware Horizon
id: 3eb91f0a-0060-424a-a676-59f5fdd75610
status: test
description: |
    Detects potential initial exploitation attempts against VMware Horizon deployments running a vulnerable versions of Log4j.
references:
    - https://portswigger.net/daily-swig/vmware-horizon-under-attack-as-china-based-ransomware-group-targets-log4j-vulnerability
    - https://twitter.com/TheDFIRReport/status/1482078434327244805
    - https://www.pwndefend.com/2022/01/07/log4shell-exploitation-and-hunting-on-vmware-horizon-cve-2021-44228/
author: '@kostastsale'
date: 2022-01-14
tags:
    - attack.initial-access
    - attack.t1190
    - cve.2021-44228
    - detection.emerging-threats
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\ws_TomcatService.exe'
    filter_main_shells:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unlikely
level: high

Stages and Predicates

Stage 0: condition

selection and not 1 of filter_main_*

Stage 1: selection

selection:
    ParentImage|endswith: '\ws_TomcatService.exe'

Stage 2: not filter_main_shells

filter_main_shells:
    Image|endswith:
        - '\cmd.exe'
        - '\powershell.exe'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

FieldKindExcluded values
Imageends_with\cmd.exe
Imageends_with\powershell.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
ParentImageends_with
  • \ws_TomcatService.exe corpus 6 (sigma 6)