Windows EFI Volume Mount Attempt Via Mountvol
Detects attempts to mount the EFI volume. The EFI system partition (ESP) is a special partition on a data storage device (usually a hard disk drive or solid-state drive) that computers adhering to the UEFI (Unified…
Description
Detects attempts to mount the EFI volume. The EFI system partition (ESP) is a special partition on a data storage device (usually a hard disk drive or solid-state drive) that computers adhering to the UEFI (Unified Extensible Firmware Interface) specification use to store data necessary for the system to boot, such as bootloaders, device drivers, and system utilities. This is used with attacks such as PKFail to modify the system on boot.
Detection logic
Detection requirements
- Platform
- LinuxmacOSNetwork DevicesWindows
The rule states no platform. This is derived from the 3 ATT&CK techniques it maps to.
- Log source category
- crowdstrike_processrollup2sysmon_eventid_1windows_event_log_security_4688
Known benign triggers
- Mounting the EFI volume can be part of normal system updates or legitimate maintenance tasks. Monitor for unusual timing or context to reduce false alerts.
MITRE ATT&CK mappings
1 exclusive technique.This is coverage no other published rule has; it is not this rule's total technique count.
References
| Reference | Cited by |
|---|---|
| www.binarly.io/blog/pkfail-untrusted-platform-keys-undermine-secure-boot-on-uefi-ecosystem | Only this detection cites it |
From the source
- At source
- Open at source
- Upstream identifier
- 6ee1d152-56c7-40e8-8db0-edb0074a6bb2
- Tagged by the source as
- Compromised Windows HostEndpointendpointSplunk CloudSplunk EnterpriseSplunk Enterprise Securityendpoint
Licence
- Published under
- Apache License 2.0Read the licence
- Attribution
- Required
- Obtained under
- Apache-2.0Read the origin licence
Authorship
- Written by
- Published
- Aug 26, 2026
- Version
- 1