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DET0150 Detection Strategy for File Creation or Modification of Boot Files

Item Value
ID DET0150
Version 1.0
Created 21 October 2025
Last Modified 21 October 2025

Technique Detected: T1542.003 (Bootkit)

Analytics

Windows

AN0428

Detection of raw access to physical drives, modification of boot records (MBR/VBR), and suspicious file creation or alteration within the EFI System Partition (ESP). Correlates privileged process execution with low-level disk modification and unexpected driver or firmware interactions.

Log Sources
Data Component Name Channel
Drive Access (DC0054) WinEventLog:Sysmon EventCode=9
File Creation (DC0039) WinEventLog:Sysmon EventCode=11
Mutable Elements
Field Description
KnownGoodMBRHashes Baseline hashes of clean MBR/VBR sectors for comparison
ESPFileWhitelist Approved EFI executables within ESP directories
TimeWindow Correlation window between privileged access, raw disk modification, and EFI file creation

Linux

AN0429

Detection of suspicious write operations to block devices, modifications of bootloader files (GRUB, initrd, vmlinuz), and unexpected changes within the EFI System Partition. Monitors privileged execution of utilities like dd, grub-install, or efibootmgr that modify boot sectors or loader entries.

Log Sources
Data Component Name Channel
File Modification (DC0061) auditd:SYSCALL open, write: Write operations targeting /dev/sda, /dev/nvme0n1, or EFI partition mounts
Drive Modification (DC0046) linux:syslog Block device write errors or unusual bootloader activity
Mutable Elements
Field Description
BootloaderHashBaseline Baseline checksums of GRUB, kernel, and initramfs images
EFIFileAllowlist Trusted EFI executables for Linux environments
AlertThresholds Tunable thresholds for triggering alerts on repeated EFI/bootloader writes