Windows Privilege Escalation Attempt Via MSI Rollback
Description
Detects an attacker abusing the Windows Installer rollback mechanism to escalate privileges from a standard user to SYSTEM without triggering a UAC prompt, using a technique known as FolderContentsDeleteToFolderDelete. Windows Installer (msiexec.exe) creates rollback scripts during software installation to undo changes if an installation fails. These rollback scripts are generated and executed by the Windows Installer service, which runs as SYSTEM. The FolderContentsDeleteToFolderDelete technique abuses this trusted mechanism by crafting a malicious rollback script that instructs the SYSTEM-level Installer service to delete attacker-chosen files or directories — effectively giving a low-privileged attacker the ability to make SYSTEM-level filesystem modifications without any privilege prompt.
Query · spl
| tstats `security_content_summariesonly`
count min(_time) as firstTime
max(_time) as lastTime
from datamodel=Endpoint.Processes where
Processes.process="*/target \"C:\\Config.msi\" *"
Processes.process="*/initial*"
by Processes.process Processes.vendor_product Processes.user_id Processes.process_hash
Processes.parent_process_name Processes.parent_process_exec Processes.action
Processes.dest Processes.process_current_directory Processes.process_path
Processes.process_integrity_level Processes.original_file_name Processes.parent_process
Processes.parent_process_path Processes.parent_process_guid Processes.parent_process_id
Processes.process_guid Processes.process_id Processes.user Processes.process_name
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_privilege_escalation_attempt_via_msi_rollback_filter`
Implementation guide
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 maintenance scripts may use similar FolderContentsDeleteToFolderDelete commands. Review and whitelist approved tools to reduce false alerts.
Analyst notes
Known false positives: Some legitimate system cleanup or maintenance scripts may use similar FolderContentsDeleteToFolderDelete commands. Review and whitelist approved tools to reduce false alerts.