Detection: Windows Set Account Password Policy To Unlimited Via Net

Description

The following analytic detects the use of net.exe or net1.exe to configure the Windows maximum password age policy as unlimited. It leverages process creation telemetry from Endpoint Detection and Response (EDR) agents and identifies executions of the net accounts command using the /maxpwage:unlimited option. When specified, Windows configures the maximum password age with an unlimited value, effectively preventing passwords governed by the affected password policy from expiring. This behavior is significant because an adversary may modify password expiration settings to weaken credential security controls and maintain access to compromised accounts for an extended period. If confirmed malicious, this activity may indicate an attempt to establish or maintain persistence by preventing expected password rotation from invalidating credentials under the affected password policy.

Search

 1
 2| tstats `security_content_summariesonly`
 3  values(Processes.process) as process min(_time) as firstTime max(_time) as lastTime
 4
 5FROM datamodel=Endpoint.Processes WHERE
 6
 7`process_net`
 8Processes.process="* accounts *"
 9Processes.process IN ("* /maxpwage:unlimited*")
10
11BY Processes.action Processes.dest Processes.original_file_name
12   Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid
13   Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path
14   Processes.process Processes.process_exec Processes.process_guid
15   Processes.process_hash Processes.process_id Processes.process_integrity_level
16   Processes.process_name Processes.process_path Processes.user
17   Processes.user_id Processes.vendor_product
18
19
20| `drop_dm_object_name(Processes)`
21
22| `security_content_ctime(firstTime)`
23
24| `security_content_ctime(lastTime)`
25
26| `windows_set_account_password_policy_to_unlimited_via_net_filter`

Data Source

Name	Platform	Sourcetype	Source
Windows Event Log Security 4688	Windows	'XmlWinEventLog'	'XmlWinEventLog:Security'
Sysmon EventID 1	Windows	'XmlWinEventLog'	'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'
CrowdStrike ProcessRollup2	Other	'crowdstrike:events:sensor'	'crowdstrike'

Macros Used

Annotations

Default Configuration

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

Implementation

The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.

Known False Positives

This behavior is not commonly seen in production environment and not advisable, investigate the activity and determine if it is malicious. Apply additional filters to reduce false positives as needed.

Associated Analytic Story

• Crypto Stealer

• Ransomware

• XMRig

• BlackByte Ransomware

Intermediate Findings

Threat Objects

References

• https://app.any.run/tasks/a6f2ffe2-e6e2-4396-ae2e-04ea0143f2d8/

• https://docs.microsoft.com/en-us/troubleshoot/windows-server/networking/net-commands-on-operating-systems

Detection Testing

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: 8