Missing Ability to Patch ROM Code

Missing an ability to patch ROM code may leave a System or System-on-Chip (SoC) in a vulnerable state.


A System or System-on-Chip (SoC) that implements a boot process utilizing security mechanisms such as Root-of-Trust (RoT) typically starts by executing code from a Read-only-Memory (ROM) component. The code in ROM is immutable, hence any security vulnerabilities discovered in the ROM code can never be fixed for the systems that are already in use.

A common weakness is that the ROM does not have the ability to patch if security vulnerabilities are uncovered after the system gets shipped. This leaves the system in a vulnerable state where an adversary can compromise the SoC.


The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

A System-on-Chip (SOC) implements a Root-of-Trust (RoT) in ROM to boot secure code. However, at times this ROM code might have security vulnerabilities and need to be patched. Since ROM is immutable, it can be impossible to patch.

ROM does not have built-in application-programming interfaces (APIs) to patch if the code is vulnerable. Implement mechanisms to patch the vulnerable ROM code.

See Also

Comprehensive Categorization: Resource Control

Weaknesses in this category are related to resource control.

Security Flow Issues

Weaknesses in this category are related to improper design of full-system security flows, including but not limited to secure boot, secure update, and hardware-device ...

Comprehensive CWE Dictionary

This view (slice) covers all the elements in CWE.

Weaknesses Introduced During Implementation

This view (slice) lists weaknesses that can be introduced during implementation.

Weaknesses Introduced During Design

This view (slice) lists weaknesses that can be introduced during design.

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