Windows Special Privileged Logon On Multiple Hosts

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Description

The following analytic leverages Event ID 4672 to identify a source user authenticating with special privileges across a large number remote endpoints. Specifically, the logic will trigger when a source user obtains special privileges across 30 or more target computers within a 5 minute timespan. Special privileges are assigned to a new logon session when sensitive privileges like SeDebugPrivilege and SeImpersonatePrivilege are assigned. This behavior could represent an adversary who is moving laterally and executing remote code across the network. It can also be triggered by other behavior like an adversary enumerating network shares. As environments differ across organizations, security teams should customize the thresholds of this detection as needed.

• Type: TTP

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

• Last Updated: 2023-03-27
• Author: Mauricio Velazco, Splunk
• ID: 4c461f5a-c2cc-4e86-b132-c262fc9edca7

Annotations

ATT&CK

ATT&CK

ID	Technique	Tactic
T1087	Account Discovery	Discovery

T1021.002

SMB/Windows Admin Shares

Lateral Movement

T1135

Network Share Discovery

Discovery

Kill Chain Phase

• Exploitation

NIST

• DE.CM

CIS20

• CIS 10

CVE

Search

 `wineventlog_security` EventCode=4672 AND NOT(Caller_User_Name IN ("DWM-1","DWM-2","DWM-3","LOCAL SERVICE","NETWORK SERVICE","SYSTEM","*$")) 
| bucket span=5m _time 
| stats dc(Computer) AS unique_targets values(Computer) as host_targets values(PrivilegeList) as privileges by _time, Caller_User_Name 
| where unique_targets > 30 
| `windows_special_privileged_logon_on_multiple_hosts_filter`

Macros

The SPL above uses the following Macros:

• wineventlog_security

windows_special_privileged_logon_on_multiple_hosts_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
• Caller_User_Name
• Computer
• PrivilegeList

How To Implement

To successfully implement this search, you need to be ingesting special logon events. The Advanced Security Audit policy setting Audit Special Logon within Logon/Logoff need to be enabled.

Known False Positives

Vulnerability scanners or system administration tools may also trigger this detection. Filter as needed.

Associated Analytic Story

• Active Directory Privilege Escalation
• Active Directory Lateral Movement

RBA

Risk Score	Impact	Confidence	Message
64.0	80	80	A source user $Caller_User_Name$ obtained special privileges on a large number of endpoints within 5 minutes.

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

• https://learn.microsoft.com/en-us/windows/security/threat-protection/auditing/event-4672
• https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-r2-and-2012/dn319113(v=ws.11)
• https://thedfirreport.com/2023/01/23/sharefinder-how-threat-actors-discover-file-shares/
• https://attack.mitre.org/tactics/TA0008/

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

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