Techniques
Sample rules
Windows EFI Volume Mount Attempt Via Mountvol
- source: splunk
- technicques:
- T1204.002
- T1542
- T1688
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
| tstats `security_content_summariesonly`
count min(_time) as firstTime
max(_time) as lastTime
from datamodel=Endpoint.Processes where
(
Processes.process_name="mountvol.exe"
OR
Processes.original_file_name="MOUNTVOL.EXE"
)
Processes.process IN ("*-S*", "* /S*")
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_efi_volume_mount_attempt_via_mountvol_filter`