Remote Access Tool - RURAT Execution From Unusual Location

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

Detects execution of Remote Utilities RAT (RURAT) from an unusual location (outside of 'C:\Program Files')

MITRE ATT&CK coverage

Tactic	Techniques
Stealth	No specific technique

Telemetry coverage

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

Rule body

title: Remote Access Tool - RURAT Execution From Unusual Location
id: e01fa958-6893-41d4-ae03-182477c5e77d
status: test
description: Detects execution of Remote Utilities RAT (RURAT) from an unusual location (outside of 'C:\Program Files')
references:
    - https://redcanary.com/blog/misbehaving-rats/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-09-19
modified: 2023-03-05
tags:
    - attack.stealth
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        - Image|endswith:
              - '\rutserv.exe'
              - '\rfusclient.exe'
        - Product: 'Remote Utilities'
    filter:
        Image|startswith:
            - 'C:\Program Files\Remote Utilities'
            - 'C:\Program Files (x86)\Remote Utilities'
    condition: selection and not filter
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: `condition`

selection and not filter

Stage 1: `selection`

selection:
    - Image|endswith:
          - '\rutserv.exe'
          - '\rfusclient.exe'
    - Product: 'Remote Utilities'

Stage 2: `not filter`

filter:
    Image|startswith:
        - 'C:\Program Files\Remote Utilities'
        - 'C:\Program Files (x86)\Remote Utilities'

Exclusions

The rule actively suppresses these predicates.

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

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`Image`	ends_with	`\rfusclient.exe` `\rutserv.exe`	`field:"Image" kind:ends_with`
`Product`	eq	`Remote Utilities` corpus 2 (sigma 2)	`field:"Product" kind:eq value:"Remote Utilities"`