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T0857 System Firmware

System firmware on modern assets is often designed with an update feature. Older device firmware may be factory installed and require special reprograming equipment. When available, the firmware update feature enables vendors to remotely patch bugs and perform upgrades. Device firmware updates are often delegated to the user and may be done using a software update package. It may also be possible to perform this task over the network.

An adversary may exploit the firmware update feature on accessible devices to upload malicious or out-of-date firmware. Malicious modification of device firmware may provide an adversary with root access to a device, given firmware is one of the lowest programming abstraction layers. 1

Item Value
ID T0857
Tactics TA0110, TA0107
Platforms Field Controller/RTU/PLC/IED, Input/Output Server, Safety Instrumented System/Protection Relay
Version 1.1
Created 21 May 2020
Last Modified 09 March 2023

Procedure Examples

ID Name Description
G0034 Sandworm Team In the Ukraine 2015 Incident, Sandworm Team developed and used malicious firmware to render communication devices inoperable. 7
S1009 Triton Triton is able to read, write and execute code in memory on the safety controller at an arbitrary address within the devices firmware region. This allows the malware to make changes to the running firmware in memory and modify how the device operates. 6


ID Mitigation Description
M0801 Access Management All devices or systems changes, including all administrative functions, should require authentication. Consider using access management technologies to enforce authorization on all management interface access attempts, especially when the device does not inherently provide strong authentication and authorization functions.
M0947 Audit Perform integrity checks of firmware before uploading it on a device. Utilize cryptographic hashes to verify the firmware has not been tampered with by comparing it to a trusted hash of the firmware. This could be from trusted data sources (e.g., vendor site) or through a third-party verification service.
M0946 Boot Integrity Check the integrity of the existing BIOS or EFI to determine if it is vulnerable to modification. Use Trusted Platform Module technology. 5 Move system’s root of trust to hardware to prevent tampering with the SPI flash memory. 3 Technologies such as Intel Boot Guard can assist with this. 4
M0945 Code Signing Devices should verify that firmware has been properly signed by the vendor before allowing installation.
M0802 Communication Authenticity Protocols used for device management should authenticate all network messages to prevent unauthorized system changes.
M0808 Encrypt Network Traffic The encryption of firmware should be considered to prevent adversaries from identifying possible vulnerabilities within the firmware.
M0941 Encrypt Sensitive Information The encryption of firmware should be considered to prevent adversaries from identifying possible vulnerabilities within the firmware.
M0937 Filter Network Traffic Filter for protocols and payloads associated with firmware activation or updating activity.
M0804 Human User Authentication Devices that allow remote management of firmware should require authentication before allowing any changes. The authentication mechanisms should also support Account Use Policies, Password Policies, and User Account Management.
M0807 Network Allowlists Use host-based allowlists to prevent devices from accepting connections from unauthorized systems. For example, allowlists can be used to ensure devices can only connect with master stations or known management/engineering workstations. 2
M0930 Network Segmentation Segment operational network and systems to restrict access to critical system functions to predetermined management systems. 2
M0813 Software Process and Device Authentication Authenticate connections fromsoftware and devices to prevent unauthorized systems from accessing protected management functions.
M0951 Update Software Patch the BIOS and EFI as necessary.


ID Data Source Data Component
DS0015 Application Log Application Log Content
DS0001 Firmware Firmware Modification
DS0029 Network Traffic Network Traffic Content
DS0040 Operational Databases Device Alarm