T1542.001sub-technique of T1542 Pre-OS Boot

System Firmware

Network Devices · Windowsnothing on this site yetT1542.001 on attack.mitre.org

Adversaries may modify system firmware to persist on systems.The BIOS (Basic Input/Output System) and The Unified Extensible Firmware Interface (UEFI) or Extensible Firmware Interface (EFI) are examples of system firmware that operate as the software interface between the operating system and hardware of a computer.

MITRE ATT&CK 19.2, retrieved 2026-09-12

If this is happening now

1

Checklists and playbooks to open while the alert is still live.

how MITRE says to see it

Detection Strategy for T1542.001 Pre-OS Boot: System Firmware

  • Unexpected write operations to BIOS/UEFI firmware regions or EFI boot partitions that do not correlate with legitimate vendor firmware updates. API calls or utilities such as fwupdate.exe or vendor flash tools executed from non-administrative or non-IT management accounts.
  • Unauthorized firmware uploads to routers, switches, or firewalls via TFTP/FTP/SCP. Logs showing boot variable or startup image path changes redirecting to non-standard firmware images. Abnormal reboots or firmware rollback attempts following configuration modification events.

what reduces it

  • M1046 Boot Integrity. Check the integrity of the existing BIOS or EFI to determine if it is vulnerable to modification. Use Trusted Platform Module technology. Move system's root of trust to hardware to prevent tampering with the SPI flash memory. Technologies such as Intel Boot Guard can assist with this.
  • M1026 Privileged Account Management. Prevent adversary access to privileged accounts or access necessary to perform this technique.
  • M1051 Update Software. Patch the BIOS and EFI as necessary.

the rest of T1542

The description, detection analytics and mitigations are reproduced from MITRE ATT&CK, version 19.2, under its terms of use. The checklists, hunts, labs and everything else linked here are this site’s.