Rundll32 Registered COM Objects

Status: test
Severity: high
Log source: category process_creation, product windows
Author: frack113
Source: github.com/SigmaHQ/sigma

load malicious registered COM objects

Known false positives

Legitimate use

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1546.015` Event Triggered Execution: Component Object Model Hijacking
Privilege Escalation	`T1546.015` Event Triggered Execution: Component Object Model Hijacking

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation

Rule body

title: Rundll32 Registered COM Objects
id: f1edd233-30b5-4823-9e6a-c4171b24d316
status: test
description: load malicious registered COM objects
references:
    - https://nasbench.medium.com/a-deep-dive-into-rundll32-exe-642344b41e90
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1546.015/T1546.015.md
author: frack113
date: 2022-02-13
modified: 2023-02-09
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1546.015
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\rundll32.exe'
        - OriginalFileName: 'RUNDLL32.EXE'
    selection_cli:
        CommandLine|contains:
            - '-sta '
            - '-localserver '
        CommandLine|contains|all:
            - '{'
            - '}'
    condition: all of selection_*
falsepositives:
    - Legitimate use
level: high

Stages and Predicates

Stage 0: `condition`

all of selection_*

Stage 1: `selection_img`

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

Stage 2: `selection_cli`

selection_cli:
    CommandLine|contains:
        - '-sta '
        - '-localserver '
    CommandLine|contains|all:
        - '{'
        - '}'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CommandLine`	match	`-localserver` `-sta` `{` corpus 2 (sigma 1, splunk 1) `}` corpus 2 (sigma 1, splunk 1)	`field:"CommandLine" kind:match`
`Image`	ends_with	`\rundll32.exe` corpus 94 (sigma 94)	`field:"Image" kind:ends_with value:"\rundll32.exe"`
`OriginalFileName`	eq	`RUNDLL32.EXE` corpus 78 (sigma 35, elastic 22, splunk 21)	`field:"OriginalFileName" kind:eq value:"RUNDLL32.EXE"`

Rundll32 Registered COM Objects

Known false positives

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection_img

Stage 2: selection_cli

Indicators

Stage 0: `condition`

Stage 1: `selection_img`

Stage 2: `selection_cli`