ServicePrincipalNames Discovery with PowerShell

Name:ServicePrincipalNames Discovery with PowerShell
id:13243068-2d38-11ec-8908-acde48001122
version:4
date:2024-09-30
author:Michael Haag, Splunk
status:production
type:TTP
Description:The following analytic detects the use of `powershell.exe` to query the domain for Service Principal Names (SPNs) using Script Block Logging EventCode 4104. It identifies the use of the KerberosRequestorSecurityToken class within the script block, which is equivalent to using setspn.exe. This activity is significant as it often precedes kerberoasting or silver ticket attacks, which can lead to credential theft. If confirmed malicious, attackers could leverage this information to escalate privileges or persist within the environment.
Data_source:

• -Powershell Script Block Logging 4104

search:`powershell` EventCode=4104 ScriptBlockText="*KerberosRequestorSecurityToken*"
| stats count min(_time) as firstTime max(_time) as lastTime by ScriptBlockText Opcode Computer UserID EventCode
| rename Computer as dest
| rename UserID as user
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `serviceprincipalnames_discovery_with_powershell_filter`

how_to_implement:To successfully implement this analytic, you will need to enable PowerShell Script Block Logging on some or all endpoints. Additional setup here https://docs.splunk.com/Documentation/UBA/5.0.4.1/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell.
known_false_positives:False positives should be limited, however filter as needed.
References:
  -https://docs.microsoft.com/en-us/windows/win32/ad/service-principal-names
  -https://docs.microsoft.com/en-us/dotnet/api/system.identitymodel.tokens.kerberosrequestorsecuritytoken?view=netframework-4.8
  -https://www.ired.team/offensive-security-experiments/active-directory-kerberos-abuse/t1208-kerberoasting
  -https://strontic.github.io/xcyclopedia/library/setspn.exe-5C184D581524245DAD7A0A02B51FD2C2.html
  -https://attack.mitre.org/techniques/T1558/003/
  -https://social.technet.microsoft.com/wiki/contents/articles/717.service-principal-names-spn-setspn-syntax.aspx
  -https://web.archive.org/web/20220212163642/https://www.harmj0y.net/blog/powershell/kerberoasting-without-mimikatz/
  -https://blog.zsec.uk/paving-2-da-wholeset/
  -https://msitpros.com/?p=3113
  -https://adsecurity.org/?p=3466
  -https://docs.splunk.com/Documentation/UBA/5.0.4.1/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell.
  -https://blog.palantir.com/tampering-with-windows-event-tracing-background-offense-and-defense-4be7ac62ac63
  -https://static1.squarespace.com/static/552092d5e4b0661088167e5c/t/59c1814829f18782e24f1fe2/1505853768977/Windows+PowerShell+Logging+Cheat+Sheet+ver+Sept+2017+v2.1.pdf
  -https://www.crowdstrike.com/blog/investigating-powershell-command-and-script-logging/
drilldown_searches:
 name:'View the detection results for - "$user$" and "$dest$"'
 search:'%original_detection_search% | search user = "$user$" dest = "$dest$"'
 earliest_offset:'$info_min_time$'
 latest_offset:'$info_max_time$'
 name:'View risk events for the last 7 days for - "$user$" and "$dest$"'
 search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") starthoursago=168 | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
 earliest_offset:'$info_min_time$'
 latest_offset:'$info_max_time$'
tags:
  analytic_story:
    - 'Active Directory Discovery'
    - 'Active Directory Kerberos Attacks'
    - 'Malicious PowerShell'
    - 'Active Directory Privilege Escalation'
  asset_type:Endpoint
  confidence:100
  impact:80
  message:An instance of attempting to identify service principle detected on $dest$ names.
  mitre_attack_id:
    - 'T1558.003'
  observable:
    name:'user'
    type:'User'
    - role:
      - 'Victim'
    name:'dest'
    type:'Hostname'
    - role:
      - 'Victim'
  product:
    - 'Splunk Enterprise'
    - 'Splunk Enterprise Security'
    - 'Splunk Cloud'
  required_fields:
    - '_time'
    - 'ScriptBlockText'
    - 'Opcode'
    - 'Computer'
    - 'UserID'
    - 'EventCode'
  risk_score:80
  security_domain:endpoint

tests:
 name:'True Positive Test'
 attack_data:
  data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1059.001/powershell_script_block_logging/sbl_xml.log
  source: XmlWinEventLog:Microsoft-Windows-PowerShell/Operational
  sourcetype: XmlWinEventLog
manual_test:None