System Firmware
Where this stands
One published detection covers this technique. Every one is unverified — no rule on Siemphony has been executed against real telemetry.
What the technique is
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. System firmware like BIOS and (U)EFI underly the functionality of a computer and may be modified by an adversary to perform or assist in malicious activity. Capabilities exist to overwrite the system firmware, which may give sophisticated adversaries a means to install malicious firmware updates as a means of persistence on a system that may be difficult to detect.
Read it on attack.mitre.orgWhat MITRE says you would watch
- AN0275
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. Suspicious raw disk writes targeting System Firmware GUID partitions followed by abnormal reboot sequences.
- AN0276
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.
Technique names and descriptions © MITRE ATT&CK®, CC BY 4.0. Not endorsed by MITRE.