Detection: Microsoft SharePoint Server Elevation of Privilege

Updated Date: 2024-11-15 ID: fcf4bd3f-a79f-4b7a-83bf-2692d60b859d Author: Michael Haag, Gowthamaraj Rajendran, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects potential exploitation attempts against Microsoft SharePoint Server vulnerability CVE-2023-29357. It leverages the Web datamodel to monitor for specific API calls and HTTP methods indicative of privilege escalation attempts. This activity is significant as it may indicate an attacker is trying to gain unauthorized privileged access to the SharePoint environment. If confirmed malicious, the impact could include unauthorized access to sensitive data, potential data theft, and further compromise of the SharePoint server, leading to a broader security breach.

1
2| tstats count min(_time) as firstTime max(_time) as lastTime from datamodel=Web where Web.url IN ("/_api/web/siteusers*","/_api/web/currentuser*") Web.status=200 Web.http_method=GET by Web.http_user_agent, Web.status Web.http_method, Web.url, Web.url_length, Web.src, Web.dest, sourcetype 
3| `drop_dm_object_name("Web")` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `microsoft_sharepoint_server_elevation_of_privilege_filter`

Data Source

Name Platform Sourcetype Source
Suricata N/A 'suricata' 'suricata'

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
microsoft_sharepoint_server_elevation_of_privilege_filter search *
microsoft_sharepoint_server_elevation_of_privilege_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
T1068 Exploitation for Privilege Escalation Privilege Escalation
Exploitation
DE.CM
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 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

This detection requires the Web datamodel to be populated from a supported Technology Add-On like Splunk for Microsoft SharePoint.

Known False Positives

False positives may occur if there are legitimate activities that mimic the exploitation pattern. It's recommended to review the context of the alerts and adjust the analytic parameters to better fit the specific environment.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

Possible exploitation of CVE-2023-29357 against $dest$ from $src$.

Risk Object Risk Object Type Risk Score Threat Objects
dest system 45 src

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset suricata suricata
Integration ✅ Passing Dataset suricata suricata

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: 4