Modification of Accessibility Features

id: d714ef62-1a56-4779-804f-91c4158e528d
name: Modification of Accessibility Features
description: |
  'Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by accessibility features. Windows contains accessibility features that may be launched with a key combination before a user has logged in (ex: when the user is on the Windows logon screen). An adversary can modify the way these programs are launched to get a command prompt or backdoor without logging in to the system.
  Two common accessibility programs are C:\Windows\System32\sethc.exe, launched when the shift key is pressed five times and C:\Windows\System32\utilman.exe, launched when the Windows + U key combination is pressed. The sethc.exe program is often referred to as "sticky keys", and has been used by adversaries for unauthenticated access through a remote desktop login screen. [1]
  Ref: https://attack.mitre.org/techniques/T1546/008/'
severity: Medium
requiredDataConnectors:
  - connectorId: SecurityEvents
    dataTypes:
      - SecurityEvent
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Persistence
relevantTechniques:
  - T1546.008
query: |
  let ImagesList = dynamic (["sethc.exe","utilman.exe","osk.exe","Magnify.exe","Narrator.exe","DisplaySwitch.exe","AtBroker.exe"]); 
  let OriginalFileNameList = dynamic (["sethc.exe","utilman.exe","osk.exe","Magnify.exe","Narrator.exe","DisplaySwitch.exe","AtBroker.exe","SR.exe","utilman2.exe","ScreenMagnifier.exe"]); 
  Event
  | where EventLog == "Microsoft-Windows-Sysmon/Operational" and EventID==1
  | parse EventData with * 'ProcessId">' ProcessId "<" * 'Image">' Image "<" * 'OriginalFileName">' OriginalFileName "<" *
  | where Image has_any (ImagesList) and not (OriginalFileName has_any (OriginalFileNameList))
  | parse EventData with * 'ProcessGuid">' ProcessGuid "<" * 'Description">' Description "<" * 'CommandLine">' CommandLine "<" * 'CurrentDirectory">' CurrentDirectory "<" * 'User">' User "<" * 'LogonGuid">' LogonGuid "<" * 'Hashes">' Hashes "<" * 'ParentProcessGuid">' ParentProcessGuid "<" * 'ParentImage">' ParentImage "<" * 'ParentCommandLine">' ParentCommandLine "<" * 'ParentUser">' ParentUser "<" *
  | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by EventID, Computer, User, ParentImage, ParentProcessGuid, ParentCommandLine, ParentUser, Image, ProcessId, ProcessGuid, CommandLine, Description, OriginalFileName, CurrentDirectory, Hashes
  | extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
  | extend AccountName = tostring(split(User, "\\")[1]), AccountNTDomain = tostring(split(User, "\\")[0])
  | extend ImageFileName = tostring(split(Image, "\\")[-1])
  | extend ImageDirectory = replace_string(Image, ImageFileName, "")
  | project-away DomainIndex
entityMappings:
  - entityType: Process
    fieldMappings:
      - identifier: CommandLine
        columnName: CommandLine
      - identifier: ProcessId
        columnName: ProcessId
  - entityType: Host
    fieldMappings:
      - identifier: FullName
        columnName: Computer
      - identifier: HostName
        columnName: HostName
      - identifier: DnsDomain
        columnName: HostNameDomain
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: User
      - identifier: Name
        columnName: AccountName
      - identifier: NTDomain
        columnName: AccountNTDomain
  - entityType: File
    fieldMappings:
      - identifier: Name
        columnName: ImageFileName
      - identifier: Directory
        columnName: ImageDirectory
version: 1.0.4
kind: Scheduled
metadata:
    source:
        kind: Community
    author:
        name: Vasileios Paschalidis
    support:
        tier: Community
    categories:
        domains: [ "Security - Others" ]