DSRM Account Abuse

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Id	979c42dd-533e-4ede-b18b-31a84ba8b3d6
Rulename	DSRM Account Abuse
Description	This query detects an abuse of the DSRM account in order to maintain persistence and access to the organization’s Active Directory. Ref: https://adsecurity.org/?p=1785
Severity	High
Tactics	Persistence
Techniques	T1098
Required data connectors	SecurityEvents
Kind	Scheduled
Query frequency	1h
Query period	1h
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/DSRMAccountAbuse.yaml
Version	1.0.3
Arm template	979c42dd-533e-4ede-b18b-31a84ba8b3d6.json

KQL

Event
| where EventLog == "Microsoft-Windows-Sysmon/Operational" and EventID in (13)
| parse EventData with * 'ProcessId">' ProcessId "<"* 'Image">' Image "<" * 'TargetObject">' TargetObject "<" * 'Details">' Details "<" * 'User">' User "<" * 
| where TargetObject has ("HKLM\\System\\CurrentControlSet\\Control\\Lsa\\DsrmAdminLogonBehavior") and Details == "DWORD (0x00000002)"
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by EventID, Computer, User, ProcessId, Image, TargetObject, Details, _ResourceId
| 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

YAML

description: |
  'This query detects an abuse of the DSRM account in order to maintain persistence and access to the organization's Active Directory.
  Ref: https://adsecurity.org/?p=1785'  
kind: Scheduled
tactics:
- Persistence
requiredDataConnectors:
- connectorId: SecurityEvents
  dataTypes:
  - SecurityEvent
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/DSRMAccountAbuse.yaml
severity: High
name: DSRM Account Abuse
metadata:
  support:
    tier: Community
  author:
    name: Vasileios Paschalidis
  categories:
    domains:
    - Security - Others
  source:
    kind: Community
triggerThreshold: 0
queryPeriod: 1h
query: |
  Event
  | where EventLog == "Microsoft-Windows-Sysmon/Operational" and EventID in (13)
  | parse EventData with * 'ProcessId">' ProcessId "<"* 'Image">' Image "<" * 'TargetObject">' TargetObject "<" * 'Details">' Details "<" * 'User">' User "<" * 
  | where TargetObject has ("HKLM\\System\\CurrentControlSet\\Control\\Lsa\\DsrmAdminLogonBehavior") and Details == "DWORD (0x00000002)"
  | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by EventID, Computer, User, ProcessId, Image, TargetObject, Details, _ResourceId
  | 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  
relevantTechniques:
- T1098
id: 979c42dd-533e-4ede-b18b-31a84ba8b3d6
queryFrequency: 1h
entityMappings:
- entityType: Host
  fieldMappings:
  - columnName: Computer
    identifier: FullName
  - columnName: HostName
    identifier: HostName
  - columnName: HostNameDomain
    identifier: DnsDomain
- entityType: Account
  fieldMappings:
  - columnName: User
    identifier: FullName
  - columnName: AccountName
    identifier: Name
  - columnName: AccountNTDomain
    identifier: NTDomain
- entityType: Process
  fieldMappings:
  - columnName: ProcessId
    identifier: ProcessId
- entityType: File
  fieldMappings:
  - columnName: ImageFileName
    identifier: Name
  - columnName: ImageDirectory
    identifier: Directory
- entityType: RegistryKey
  fieldMappings:
  - columnName: TargetObject
    identifier: Key
triggerOperator: gt
version: 1.0.3

ARM