Registry Persistence via AppInit DLLs Modification

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Id	9367dff0-941d-44e2-8875-cb48570c7add
Rulename	Registry Persistence via AppInit DLLs Modification
Description	Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by AppInit DLLs loaded into processes. Dynamic-link libraries (DLLs) that are specified in the AppInit_DLLs value in the Registry keys HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Windows or HKEY_LOCAL_MACHINE\Software\Wow6432Node\Microsoft\Windows NT\CurrentVersion\Windows are loaded by user32.dll into every process that loads user32.dll. In practice this is nearly every program, since user32.dll is a very common library. Ref: https://attack.mitre.org/techniques/T1546/010/
Severity	Medium
Tactics	Persistence
Techniques	T1546.010
Required data connectors	SecurityEvents WindowsSecurityEvents
Kind	Scheduled
Query frequency	1h
Query period	1h
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Endpoint Threat Protection Essentials/Analytic Rules/RegistryPersistenceViaAppInt_DLLsModification.yaml
Version	1.0.3
Arm template	9367dff0-941d-44e2-8875-cb48570c7add.json

KQL

Event
| where EventLog =~ "Microsoft-Windows-Sysmon/Operational" and EventID in (13)
| parse EventData with * 'TargetObject">' TargetObject "<" * 'Details">' Details "<" * 
| where TargetObject has "\\Windows NT\\CurrentVersion\\Windows\\AppInit_DLLs"
| summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated) by EventID, Computer, TargetObject, Details
| extend HostName = iif(Computer has '.',substring(Computer,0,indexof(Computer,'.')),Computer) , DnsDomain = iif(Computer has '.',substring(Computer,indexof(Computer,'.')+1),'')

YAML

tactics:
- Persistence
triggerOperator: gt
queryPeriod: 1h
queryFrequency: 1h
requiredDataConnectors:
- dataTypes:
  - SecurityEvent
  connectorId: SecurityEvents
- dataTypes:
  - SecurityEvent
  connectorId: WindowsSecurityEvents
status: Available
id: 9367dff0-941d-44e2-8875-cb48570c7add
relevantTechniques:
- T1546.010
triggerThreshold: 0
kind: Scheduled
entityMappings:
- fieldMappings:
  - identifier: Key
    columnName: TargetObject
  entityType: RegistryKey
- fieldMappings:
  - identifier: FullName
    columnName: Computer
  - identifier: HostName
    columnName: HostName
  - identifier: DnsDomain
    columnName: DnsDomain
  entityType: Host
query: |
  Event
  | where EventLog =~ "Microsoft-Windows-Sysmon/Operational" and EventID in (13)
  | parse EventData with * 'TargetObject">' TargetObject "<" * 'Details">' Details "<" * 
  | where TargetObject has "\\Windows NT\\CurrentVersion\\Windows\\AppInit_DLLs"
  | summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated) by EventID, Computer, TargetObject, Details
  | extend HostName = iif(Computer has '.',substring(Computer,0,indexof(Computer,'.')),Computer) , DnsDomain = iif(Computer has '.',substring(Computer,indexof(Computer,'.')+1),'')  
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Endpoint Threat Protection Essentials/Analytic Rules/RegistryPersistenceViaAppInt_DLLsModification.yaml
name: Registry Persistence via AppInit DLLs Modification
version: 1.0.3
severity: Medium
description: |
  'Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by AppInit DLLs loaded into processes. 
  Dynamic-link libraries (DLLs) that are specified in the AppInit_DLLs value in the Registry keys HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Windows or HKEY_LOCAL_MACHINE\Software\Wow6432Node\Microsoft\Windows NT\CurrentVersion\Windows are loaded by user32.dll into every process that loads user32.dll. In practice this is nearly every program, since user32.dll is a very common library.
  Ref: https://attack.mitre.org/techniques/T1546/010/'

ARM