Detection: Windows MOVEit Transfer Writing ASPX

Updated Date: 2025-06-16 ID: c0ed2aca-5666-45b3-813f-ddfac3f3eda0 Author: Michael Haag, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the creation of new ASPX files in the MOVEit Transfer application's "wwwroot" directory. It leverages endpoint data on process and filesystem activity to identify processes responsible for creating these files. This activity is significant as it may indicate exploitation of a critical zero-day vulnerability in MOVEit Transfer, used by threat actors to install malicious ASPX files. If confirmed malicious, this could lead to exfiltration of sensitive data, including user credentials and file metadata, posing a severe risk to the organization's security.

 1
 2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
 3as lastTime FROM datamodel=Endpoint.Filesystem where 
 4  Filesystem.file_path IN ("*\\MOVEitTransfer\\wwwroot\\*") AND 
 5  Filesystem.file_name IN("*.ashx", "*.asp*")
 6by Filesystem.action Filesystem.dest Filesystem.file_access_time Filesystem.file_create_time 
 7Filesystem.file_hash Filesystem.file_modify_time Filesystem.file_name Filesystem.file_path 
 8Filesystem.file_acl Filesystem.file_size Filesystem.process_guid Filesystem.process_id 
 9Filesystem.user Filesystem.vendor_product 
10
11| `drop_dm_object_name(Filesystem)` 
12
13| `security_content_ctime(firstTime)`
14
15| `security_content_ctime(lastTime)` 
16
17| `windows_moveit_transfer_writing_aspx_filter`

Data Source

Name Platform Sourcetype Source
Sysmon EventID 11 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
windows_moveit_transfer_writing_aspx_filter search *
windows_moveit_transfer_writing_aspx_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
T1133 External Remote Services Initial Access
Delivery
Installation
DE.CM
CIS 10

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 information on process that include the name of the process responsible for the changes from your endpoints into the Endpoint datamodel in the Processes node and Filesystem node.

Known False Positives

The query is structured in a way that action (read, create) is not defined. Review the results of this query, filter, and tune as necessary. It may be necessary to generate this query specific to your endpoint product.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

The MOVEit application on $dest$ has written a new ASPX file $file_name$ to disk.

Risk Object Risk Object Type Risk Score Threat Objects
dest system 100 file_name

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset XmlWinEventLog:Microsoft-Windows-Sysmon/Operational XmlWinEventLog
Integration ✅ Passing Dataset XmlWinEventLog:Microsoft-Windows-Sysmon/Operational 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: 7