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Detection rules › Sigma

Suspicious Debugger Registration Cmdline

Status
test
Severity
high
Log source
product windows, category process_creation
Author
Florian Roth (Nextron Systems), oscd.community, Jonhnathan Ribeiro
Source
github.com/SigmaHQ/sigma

Detects the registration of a debugger for a program that is available in the logon screen (sticky key backdoor).

MITRE ATT&CK coverage

TacticTechniques
PersistenceT1546.008 Event Triggered Execution: Accessibility Features
Privilege EscalationT1546.008 Event Triggered Execution: Accessibility Features

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation
Security-AuditingEvent ID 4688A new process has been created.

Rule body yaml

title: Suspicious Debugger Registration Cmdline
id: ae215552-081e-44c7-805f-be16f975c8a2
status: test
description: Detects the registration of a debugger for a program that is available in the logon screen (sticky key backdoor).
references:
    - https://blogs.technet.microsoft.com/jonathantrull/2016/10/03/detecting-sticky-key-backdoors/
    - https://bazaar.abuse.ch/sample/6f3aa9362d72e806490a8abce245331030d1ab5ac77e400dd475748236a6cc81/
author: Florian Roth (Nextron Systems), oscd.community, Jonhnathan Ribeiro
date: 2019-09-06
modified: 2022-08-06
tags:
    - attack.persistence
    - attack.privilege-escalation
    - attack.t1546.008
logsource:
    category: process_creation
    product: windows
detection:
    selection1:
        CommandLine|contains: '\CurrentVersion\Image File Execution Options\'
    selection2:
        CommandLine|contains:
            - 'sethc.exe'
            - 'utilman.exe'
            - 'osk.exe'
            - 'magnify.exe'
            - 'narrator.exe'
            - 'displayswitch.exe'
            - 'atbroker.exe'
            - 'HelpPane.exe'
    condition: all of selection*
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

all of selection*

Stage 1: selection1

selection1:
    CommandLine|contains: '\CurrentVersion\Image File Execution Options\'

Stage 2: selection2

selection2:
    CommandLine|contains:
        - 'sethc.exe'
        - 'utilman.exe'
        - 'osk.exe'
        - 'magnify.exe'
        - 'narrator.exe'
        - 'displayswitch.exe'
        - 'atbroker.exe'
        - 'HelpPane.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
CommandLinematch
  • HelpPane.exe
  • \CurrentVersion\Image File Execution Options\
  • atbroker.exe
  • displayswitch.exe corpus 3 (sigma 3)
  • magnify.exe corpus 3 (sigma 3)
  • narrator.exe corpus 3 (sigma 3)
  • osk.exe corpus 3 (sigma 3)
  • sethc.exe corpus 4 (sigma 4)
  • utilman.exe corpus 3 (sigma 3)