Detection: Windows AD Self DACL Assignment

 1`wineventlog_security` 
 2EventCode=5136 
 3
 4| stats min(_time) as _time 
 5        values(
 6          eval(
 7            if(OperationType=="%%14675",AttributeValue,null)
 8            )
 9        ) as old_value 
10        
11        values(
12          eval(
13            if(OperationType=="%%14674" ,AttributeValue,null)
14          )
15        ) as new_value 
16        
17        values(OperationType) as OperationType 
18by ObjectClass ObjectDN OpCorrelationID src_user SubjectLogonId dest 
19
20
21| rex field=old_value max_match=10000 "\((?P<old_values>.*?)\)"
22
23| rex field=new_value max_match=10000 "\((?P<new_ace>.*?)\)" 
24
25| mvexpand new_ace
26
27| where NOT new_ace IN (old_values) 
28
29| rex field=new_ace "(?P<aceType>.*?);(?P<aceFlags>.*?);(?P<aceAccessRights>.*?);(?P<aceObjectGuid>.*?);(?P<aceInheritedTypeGuid>.*?);(?P<aceSid>.*?)$"
30
31| rex max_match=100 field=aceAccessRights "(?P<AccessRights>[A-Z]{2})" 
32
33| rex max_match=100 field=aceFlags "(?P<aceFlags>[A-Z]{2})" 
34
35
36| lookup ace_type_lookup ace_type_string as aceType OUTPUT ace_type_value as aceType 
37
38| lookup ace_flag_lookup flag_string as aceFlags OUTPUT flag_value as ace_flag_value 
39
40| lookup ace_access_rights_lookup access_rights_string as AccessRights OUTPUT access_rights_value 
41
42| lookup msad_guid_lookup guid as aceObjectGuid OUTPUT displayName as ControlAccessRights 
43
44``` Optional SID resolution lookups  
45
46| lookup identity_lookup_expanded objectSid as aceSid OUTPUT downLevelDomainName as user  
47
48| lookup admon_groups_def objectSid as aceSid OUTPUT cn as group  

  1
  2
  3### Data Source
  4
  5| Name | Platform | Sourcetype | Source |
  6|------|----------|------------|--------|
  7| [Windows Event Log Security 5136](/sources/7ba3737e-231e-455d-824e-cd077749f835) | <img src="/icons/windows.svg" alt="Windows icon" class="icon-tiny"> [Windows](/platform/windows) | `'XmlWinEventLog'` | `'XmlWinEventLog:Security'` |
  8
  9
 10
 11### Macros Used
 12
 13| Name | Value |
 14|------|-------|
 15| [wineventlog_security](https://github.com/splunk/security_content/blob/develop/macros/wineventlog_security.yml) | `eventtype="wineventlog_security" OR Channel="security" OR source="XmlWinEventLog:Security" OR source="WinEventLog:Security"` |
 16| windows_ad_self_dacl_assignment_filter | `search *` |
 17
 18
 19
 20

  windows_ad_self_dacl_assignment_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.


 21
 22
 23
 24
 25### Annotations
 26
 27
 28









  

    

      - MITRE ATT&CK
    
    

      + Kill Chain Phases
    
    

      + NIST
    
    

      + CIS
    
    

      - Threat Actors
    
  

  

    

      

        

          

            
ID
            
Technique
            
Tactic
          
        
        

          
            
            
            
            
              

                
T1484
                
Domain or Tenant Policy Modification
                
Defense Evasion
              
            
          
            
            
            
            
              

                
T1098
                
Account Manipulation
                
Privilege Escalation
              
            
          
        
      
    
  

  

    

      
        
Exploitation
      
        
Installation
      
    
  

  

    

      
        
DE.CM
      
    
  

  

    

      
        
CIS 10
      
    
  

  

    

      
        
Lazarus Group
      
        
Scattered Spider
      
        

      
    
  



 29
 30
 31
 32
 33### Default Configuration
 34<a name="default-configuration"></a>
 35
 36This detection is configured by default in Splunk Enterprise Security to run with the following settings:
 37
 38| Setting | Value |
 39|---------|-------|
 40| Disabled | true |
 41| Cron Schedule | `0 * * * *` |
 42| Earliest Time | `-70m@m` |
 43| Latest Time | `-10m@m` |
 44| Schedule Window | `auto` |
 45| Creates Notable | Yes |
 46| Rule Title | `%name%` |
 47| Rule Description | `%description%` |
 48| Notable Event Fields | user, dest |
 49| Creates Risk Event | True |
 50
 51
 52

  This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.


 53
 54
 55### Implementation
 56
 57Ensure you are ingesting Active Directory audit logs - specifically event 5136. See lantern article in references for further on how to onboard AD audit data. Ensure the wineventlog_security macro is configured with the correct indexes and include lookups for SID resolution if evt_resolve_ad_obj is set to 0.
 58
 59### Known False Positives
 60
 61No false positives have been identified at this time.
 62
 63### Associated Analytic Story
 64
 65
 66* [Sneaky Active Directory Persistence Tricks](/stories/sneaky_active_directory_persistence_tricks/)
 67
 68
 69### Risk Based Analytics (RBA)
 70
 71##### Risk Message:
 72> $user$ has created a DACL on $ObjectDN$ to grant themselves $aceControlAccessRights$ across $aceAccessRights$
 73
 74| Risk Object | Risk Object Type | Risk Score | Threat Objects |
 75|--------------|------------|--------|------------|
 76| user | user | 80 | No Threat Objects |
 77
 78
 79
 80
 81### References
 82
 83
 84* https://lantern.splunk.com/Security/Product_Tips/Enterprise_Security/Enabling_an_audit_trail_from_Active_Directory
 85
 86
 87
 88### Detection Testing
 89
 90| Test Type | Status | Dataset | Source | Sourcetype |
 91| --------- | ------ | ------- | ------ | ---------- |
 92| Validation | ✅ [Passing](https://github.com/splunk/security_content/actions/workflows/build.yml) | N/A | N/A | N/A |
 93| Unit | ✅ [Passing](https://github.com/splunk/security_content/actions/workflows/build.yml) | [Dataset](https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1484/aclmodification/windows-security-xml.log) | `XmlWinEventLog:Security` | `XmlWinEventLog` |
 94| Integration | ✅ Passing | [Dataset](https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1484/aclmodification/windows-security-xml.log) | `XmlWinEventLog:Security` | `XmlWinEventLog` |
 95
 96Replay any dataset to Splunk Enterprise by using our [`replay.py`](https://github.com/splunk/attack_data#using-replaypy) tool or the [UI](https://github.com/splunk/attack_data#using-ui).
 97Alternatively you can replay a dataset into a [Splunk Attack Range](https://github.com/splunk/attack_range#replay-dumps-into-attack-range-splunk-server)
 98
 99-----
100
101
102Source: [GitHub](https://github.com/splunk/security_content/tree/develop/detections/endpoint/windows_ad_self_dacl_assignment.yml) |
103Version: **8**