Detection rules › Sigma

Potential Process Injection Via Msra.EXE

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

Detects potential process injection via Microsoft Remote Asssistance (Msra.exe) by looking at suspicious child processes spawned from the aforementioned process. It has been a target used by many threat actors and used for discovery and persistence tactics

MITRE ATT&CK coverage

TacticTechniques
Privilege EscalationT1055 Process Injection
StealthT1055 Process Injection

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation

Rule body yaml

title: Potential Process Injection Via Msra.EXE
id: 744a188b-0415-4792-896f-11ddb0588dbc
status: test
description: Detects potential process injection via Microsoft Remote Asssistance (Msra.exe) by looking at suspicious child processes spawned from the aforementioned process. It has been a target used by many threat actors and used for discovery and persistence tactics
references:
    - https://www.microsoft.com/security/blog/2021/12/09/a-closer-look-at-qakbots-latest-building-blocks-and-how-to-knock-them-down/
    - https://www.fortinet.com/content/dam/fortinet/assets/analyst-reports/ar-qakbot.pdf
author: Alexander McDonald
date: 2022-06-24
modified: 2023-02-03
tags:
    - attack.privilege-escalation
    - attack.stealth
    - attack.t1055
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\msra.exe'
        ParentCommandLine|endswith: 'msra.exe'
        Image|endswith:
            - '\arp.exe'
            - '\cmd.exe'
            - '\net.exe'
            - '\netstat.exe'
            - '\nslookup.exe'
            - '\route.exe'
            - '\schtasks.exe'
            - '\whoami.exe'
    condition: selection
falsepositives:
    - Legitimate use of Msra.exe
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    ParentImage|endswith: '\msra.exe'
    ParentCommandLine|endswith: 'msra.exe'
    Image|endswith:
        - '\arp.exe'
        - '\cmd.exe'
        - '\net.exe'
        - '\netstat.exe'
        - '\nslookup.exe'
        - '\route.exe'
        - '\schtasks.exe'
        - '\whoami.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
Imageends_with
  • \arp.exe corpus 3 (sigma 3)
  • \cmd.exe corpus 130 (sigma 130)
  • \net.exe corpus 49 (sigma 49)
  • \netstat.exe corpus 5 (sigma 5)
  • \nslookup.exe corpus 5 (sigma 5)
  • \route.exe corpus 3 (sigma 3)
  • \schtasks.exe corpus 56 (sigma 56)
  • \whoami.exe corpus 19 (sigma 19)
ParentCommandLineends_with
  • msra.exe
ParentImageends_with
  • \msra.exe