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Description

The following analytic leverages Kerberos Event 4769, A Kerberos service ticket was requested, to identify a potential kerberoasting attack against Active Directory networks. Kerberoasting allows an adversary to request kerberos tickets for domain accounts typically used as service accounts and attempt to crack them offline allowing them to obtain privileged access to the domain. This analytic looks for a specific combination of the Ticket_Options field based on common kerberoasting tools. Defenders should be aware that it may be possible for a Kerberoast attack to use different Ticket_Options.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2022-02-09
  • Author: Jose Hernandez, Patrick Bareiss, Mauricio Velazco, Splunk
  • ID: 5cc67381-44fa-4111-8a37-7a230943f027

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1558 Steal or Forge Kerberos Tickets Credential Access
T1558.003 Kerberoasting Credential Access
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 8
  • CIS 16
CVE
1
2
3
4
5
`wineventlog_security` EventCode=4769 Service_Name!="*$" (Ticket_Options=0x40810000 OR Ticket_Options=0x40800000 OR Ticket_Options=0x40810010) Ticket_Encryption_Type=0x17 
| stats count min(_time) as firstTime max(_time) as lastTime by dest, service, service_id, Ticket_Encryption_Type, Ticket_Options 
| `security_content_ctime(lastTime)` 
| `security_content_ctime(firstTime)` 
| `kerberoasting_spn_request_with_rc4_encryption_filter`

Macros

The SPL above uses the following Macros:

:information_source: kerberoasting_spn_request_with_rc4_encryption_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • EventCode
  • Ticket_Options
  • Ticket_Encryption_Type
  • dest
  • service
  • service_id

How To Implement

To successfully implement this search, you need to be ingesting Domain Controller and Kerberos events. The Advanced Security Audit policy setting Audit Kerberos Authentication Service within Account Logon needs to be enabled.

Known False Positives

Older systems that support kerberos RC4 by default like NetApp may generate false positives. Filter as needed

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
72.0 90 80 Potential kerberoasting attack via service principal name requests detected on $dest$

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

source | version: 4