Detection: Windows IIS Server PSWA Console Access

Updated Date: 2024-11-15 ID: 914ab191-fa8a-48cb-83a6-0565e061f934 Author: Michael Haag, Splunk Type: Hunting Product: Splunk Enterprise Security

Description

This analytic detects access attempts to the PowerShell Web Access (PSWA) console on Windows IIS servers. It monitors web traffic for requests to PSWA-related URIs, which could indicate legitimate administrative activity or potential unauthorized access attempts. By tracking source IP, HTTP status, URI path, and HTTP method, it helps identify suspicious patterns or brute-force attacks targeting PSWA. This detection is crucial for maintaining the security of remote PowerShell management interfaces and preventing potential exploitation of this powerful administrative tool.

1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Web where Web.dest IN ("/pswa/*") by Web.src Web.status Web.uri_path Web.dest Web.http_method Web.uri_query 
3| `drop_dm_object_name("Web")`
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `windows_iis_server_pswa_console_access_filter`

Data Source

Name Platform Sourcetype Source
Windows IIS Windows icon Windows 'IIS:Configuration:Operational' 'IIS:Configuration:Operational'

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
windows_iis_server_pswa_console_access_filter search *
windows_iis_server_pswa_console_access_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
T1190 Exploit Public-Facing Application Initial Access
Delivery
DE.AE
CIS 13

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 Risk Event False
This configuration file applies to all detections of type hunting.

Implementation

To successfully implement this search you need to be ingesting information on Web traffic, Exchange OR IIS logs, mapped to Web datamodel in the Web node. In addition, confirm the latest CIM App 4.20 or higher is installed.

Known False Positives

False positives may occur if legitimate PSWA processes are used for administrative tasks. Careful review of the logs is recommended to distinguish between legitimate and malicious activity.

Associated Analytic Story

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset ms:iis:splunk ms:iis:splunk
Integration ✅ Passing Dataset ms:iis:splunk ms:iis:splunk

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: 3