T1542.004sub-technique of T1542 Pre-OS Boot

ROMMONkit

Network Devicesnothing on this site yetT1542.004 on attack.mitre.org

Adversaries may abuse the ROM Monitor (ROMMON) by loading an unauthorized firmware with adversary code to provide persistent access and manipulate device behavior that is difficult to detect. ROMMON is a Cisco network device firmware that functions as a boot loader, boot image, or boot helper to initialize hardware and software when the platform is powered on or reset.

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 T1542.004 Pre-OS Boot: ROMMONkit

  • Detection of anomalous ROMMON image changes or upgrades, unexpected reboots following firmware updates, and unauthorized use of firmware upgrade commands or TFTP transfers. Correlation of config modification, privilege escalation, and boot cycle anomalies provides visibility into ROMMON tampering attempts.

what reduces it

  • M1031 Network Intrusion Prevention. Network intrusion detection and prevention systems that use network signatures to identify traffic for specific protocols, such as TFTP, can be used to mitigate activity at the network level. Signatures are often for unique indicators within protocols and may be based on the specific technique used by a particular adversary or tool, and will likely be different across various network configurations.
  • M1046 Boot Integrity. Enable secure boot features to validate the digital signature of the boot environment and system image using a special purpose hardware device. If the validation check fails, the device will fail to boot preventing loading of unauthorized software.
  • M1047 Audit. Periodically check the integrity of system image to ensure it has not been modified.

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.