Suspicious Service Installation Script

Status: test
Severity: high
Log source: product windows, service system
Author: pH-T (Nextron Systems)
Source: github.com/SigmaHQ/sigma

Detects suspicious service installation scripts

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1543.003` Create or Modify System Process: Windows Service
Privilege Escalation	`T1543.003` Create or Modify System Process: Windows Service

Telemetry coverage

Provider	Record / event type
Service-Control-Manager	Event ID 7045: A service was installed in the system.

Rule body

title: Suspicious Service Installation Script
id: 70f00d10-60b2-4f34-b9a0-dc3df3fe762a
status: test
description: Detects suspicious service installation scripts
references:
    - Internal Research
author: pH-T (Nextron Systems)
date: 2022-03-18
modified: 2024-03-05
tags:
    - attack.persistence
    - attack.privilege-escalation
    - car.2013-09-005
    - attack.t1543.003
logsource:
    product: windows
    service: system
detection:
    selection_eid:
        Provider_Name: 'Service Control Manager'
        EventID: 7045
    selection_cmd_flags:
        ImagePath|contains|windash:
            - ' -c '
            - ' -r '
            - ' -k '
    selection_binaries:
        ImagePath|contains:
            - 'cscript'
            - 'mshta'
            - 'powershell'
            - 'pwsh'
            - 'regsvr32'
            - 'rundll32'
            - 'wscript'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: `condition`

all of selection_*

Stage 1: `selection_eid`

selection_eid:
    Provider_Name: 'Service Control Manager'
    EventID: 7045

Stage 2: `selection_cmd_flags`

selection_cmd_flags:
    ImagePath|contains|windash:
        - ' -c '
        - ' -r '
        - ' -k '

Stage 3: `selection_binaries`

selection_binaries:
    ImagePath|contains:
        - 'cscript'
        - 'mshta'
        - 'powershell'
        - 'pwsh'
        - 'regsvr32'
        - 'rundll32'
        - 'wscript'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`ImagePath`	match	`-c` transforms: `windash` `-k` transforms: `windash` `-r` transforms: `windash` `cscript` `mshta` corpus 2 (sigma 2) `powershell` corpus 5 (sigma 5) `pwsh` corpus 2 (sigma 2) `regsvr32` `rundll32` corpus 4 (sigma 4) `wscript`	`field:"ImagePath" kind:match`
`Provider_Name`	eq	`Service Control Manager` corpus 50 (sigma 50)	`field:"Provider_Name" kind:eq value:"Service Control Manager"`

Suspicious Service Installation Script

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection_eid

Stage 2: selection_cmd_flags

Stage 3: selection_binaries

Indicators

Stage 0: `condition`

Stage 1: `selection_eid`

Stage 2: `selection_cmd_flags`

Stage 3: `selection_binaries`