Detection: Windows AD DSRM Password Reset

Updated Date: 2024-05-12 ID: d1ab841c-36a6-46cf-b50f-b2b04b31182a Author: Dean Luxton Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects attempts to reset the Directory Services Restore Mode (DSRM) administrator password on a Domain Controller. It leverages event code 4794 from the Windows Security Event Log, specifically looking for events where the DSRM password reset is attempted. This activity is significant because the DSRM account can be used similarly to a local administrator account, providing potential persistence for an attacker. If confirmed malicious, this could allow an attacker to maintain administrative access to the Domain Controller, posing a severe risk to the domain's security.

1
2| tstats `security_content_summariesonly` min(_time) as _time from datamodel=Change where All_Changes.result_id="4794" AND All_Changes.result="An attempt was made to set the Directory Services Restore Mode administrator password" by All_Changes.action, All_Changes.dest, All_Changes.src, All_Changes.user 
3| `drop_dm_object_name(All_Changes)` 
4| `windows_ad_dsrm_password_reset_filter`

Data Source

Name Platform Sourcetype Source Supported App
Windows Event Log Security 4794 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:Security' N/A

Macros Used

Name Value
security_content_summariesonly summariesonly=summariesonly_config allow_old_summaries=oldsummaries_config fillnull_value=fillnull_config``
windows_ad_dsrm_password_reset_filter search *
windows_ad_dsrm_password_reset_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1098 Account Manipulation Persistence
KillChainPhase.EXPLOITAITON
KillChainPhase.INSTALLATION
NistCategory.DE_CM
Cis18Value.CIS_10
APT3
APT41
APT5
Dragonfly
FIN13
HAFNIUM
Kimsuky
Lazarus Group
Magic Hound

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting Value
Disabled true
Cron Schedule 0 * * * *
Earliest Time -70m@m
Latest Time -10m@m
Schedule Window auto
Creates Notable Yes
Rule Title %name%
Rule Description %description%
Notable Event Fields user, dest
Creates Risk Event True
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

To successfully implement this search, you need to be ingesting eventcode 4794 and have the Advanced Security Audit policy Audit User Account Management within Account Management enabled.

Known False Positives

Resetting the DSRM password for legitamate reasons, i.e. forgot the password. Disaster recovery. Deploying AD backdoor deliberately.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
DSRM Account Password was reset on $dest$ by $user$ 100 100 100
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset XmlWinEventLog:Security xmlwineventlog
Integration ✅ Passing Dataset XmlWinEventLog:Security xmlwineventlog

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: GitHub | Version: 2