Detection: Windows MSI Rollback Script Deleted By Non-Msiexec Process

Updated Date: 2026-04-13 ID: 6ec7cbda-9547-4f6b-8a00-d1fb4b52c1e9 Author: Raven Tait, Splunk Type: TTP Product: Splunk Enterprise Security

Description

Detects deletion of a Rollback Script (.rbs) file under C:\Config.Msi, the critical filesystem manipulation step in an MSI Rollback privilege escalation attack that converts an arbitrary file delete primitive into full SYSTEM code execution. During a legitimate MSI installation, the Windows Installer service (running as SYSTEM) creates C:\Config.Msi and populates it with a Rollback Script (.rbs) and Rollback File (.rbf). These files define exactly how to restore the system to its pre-installation state if the install fails. The folder is protected with a strong DACL specifically to prevent tampering by low-privileged users — because whatever is in these files will be executed by the SYSTEM-level Installer service during rollback.

Search

 1`sysmon`
 2EventID=23
 3TargetFilename="*:\\Config.Msi\\*"
 4TargetFilename="*.rbs"
 5NOT ProcessName="msiexec.exe"
 6
 7| fillnull
 8
 9| stats count min(_time) as firstTime
10              max(_time) as lastTime
11  by Computer ProcessName TargetFilename EventID action dest dvc file_path file_hash
12     file_name file_modify_time process_exec process_guid process_id process_name
13     process_path signature signature_id user user_id vendor_product
14
15
16| `security_content_ctime(firstTime)`
17
18| `security_content_ctime(lastTime)`
19
20| `windows_msi_rollback_script_deleted_by_non_msiexec_process_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon EventID 23	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_msi_rollback_script_deleted_by_non_msiexec_process_filter	`search *`

windows_msi_rollback_script_deleted_by_non_msiexec_process_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
T1218.007	Msiexec	Stealth
T1068	Exploitation for Privilege Escalation	Privilege Escalation

Exploitation

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

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

Some legitimate system cleanup or MSI uninstallation processes may delete rbs files under c:\Config.Msi. Verify events with approved maintenance activities to reduce false alarms.

Associated Analytic Story

Windows Privilege Escalation

Risk Based Analytics (RBA)

Risk Message:

MSI rollback script file $TargetFilename$ was deleted on $dest$ by $ProcessName$.

Risk Object	Risk Object Type	Risk Score	Threat Objects
dest	system	50	TargetFilename

References

https://github.com/mbog14/CVE-2024-44193

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: 1