Registry Persistence via AppCert DLL Modification

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Id	c61ad0ac-ad68-4ebb-b41a-74296d3e0044
Rulename	Registry Persistence via AppCert DLL Modification
Description	Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by AppCert DLLs loaded into processes. Dynamic-link libraries (DLLs) that are specified in the AppCertDLLs Registry key under HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\ are loaded into every process that calls the ubiquitously used application programming interface (API) functions CreateProcess, CreateProcessAsUser, CreateProcessWithLoginW, CreateProcessWithTokenW, or WinExec. Ref: https://attack.mitre.org/techniques/T1546/009/
Severity	Medium
Tactics	Persistence
Techniques	T1546.009
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/RegistryPersistenceViaAppCertDLLModification.yaml
Version	1.0.3
Arm template	c61ad0ac-ad68-4ebb-b41a-74296d3e0044.json

KQL

Event
| where EventLog =~ "Microsoft-Windows-Sysmon/Operational" and EventID in (13)
| parse EventData with * 'TargetObject">' TargetObject "<" * 'Details">' Details "<" * 
| where TargetObject has ("\\Control\\Session Manager\\AppCertDLLs\\")
| 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

id: c61ad0ac-ad68-4ebb-b41a-74296d3e0044
requiredDataConnectors:
- dataTypes:
  - SecurityEvent
  connectorId: SecurityEvents
- dataTypes:
  - SecurityEvent
  connectorId: WindowsSecurityEvents
name: Registry Persistence via AppCert DLL Modification
version: 1.0.3
query: |
  Event
  | where EventLog =~ "Microsoft-Windows-Sysmon/Operational" and EventID in (13)
  | parse EventData with * 'TargetObject">' TargetObject "<" * 'Details">' Details "<" * 
  | where TargetObject has ("\\Control\\Session Manager\\AppCertDLLs\\")
  | 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),'')  
entityMappings:
- fieldMappings:
  - identifier: Key
    columnName: TargetObject
  entityType: RegistryKey
- fieldMappings:
  - identifier: FullName
    columnName: Computer
  - identifier: HostName
    columnName: HostName
  - identifier: DnsDomain
    columnName: DnsDomain
  entityType: Host
relevantTechniques:
- T1546.009
tactics:
- Persistence
triggerThreshold: 0
queryPeriod: 1h
queryFrequency: 1h
severity: Medium
kind: Scheduled
triggerOperator: gt
status: Available
description: |
  'Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by AppCert DLLs loaded into processes. 
  Dynamic-link libraries (DLLs) that are specified in the AppCertDLLs Registry key under HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\ are loaded into every process that calls the ubiquitously used application programming interface (API) functions CreateProcess, CreateProcessAsUser, CreateProcessWithLoginW, CreateProcessWithTokenW, or WinExec.
  Ref: https://attack.mitre.org/techniques/T1546/009/'  
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Endpoint Threat Protection Essentials/Analytic Rules/RegistryPersistenceViaAppCertDLLModification.yaml

ARM