CWE-1274: Improper Access Control for Volatile Memory Containing Boot Code

Description

The product conducts a secure-boot process that transfers bootloader code from Non-Volatile Memory (NVM) into Volatile Memory (VM), but it does not have sufficient access control or other protections for the Volatile Memory.

Adversaries could bypass the secure-boot process and execute their own untrusted, malicious boot code. As a part of a secure-boot process, the read-only-memory (ROM) code for a System-on-Chip (SoC) or other system fetches bootloader code from Non-Volatile Memory (NVM) and stores the code in Volatile Memory (VM), such as dynamic, random-access memory (DRAM) or static, random-access memory (SRAM). The NVM is usually external to the SoC, while the VM is internal to the SoC. As the code is transferred from NVM to VM, it is authenticated by the SoC's ROM code.

Potential Impact

Demonstrative Examples

The volatile-memory protections or access controls are insufficient.

A good architecture should define appropriate protections or access controls to prevent modification by an adversary or untrusted agent, once the bootloader is authenticated.

Mitigations & Prevention

Detection Methods

• Manual Analysis High — Ensure the volatile memory is lockable or has locks. Ensure the volatile memory is locked for writes from untrusted agents or adversaries. Try modifying the volatile memory from an untrusted agent, and ensure these writes are dropped.
• Manual Analysis Moderate — Analyze the device using the following steps: Only trusted masters should be allowed to write to the memory regions. For example, pluggable device peripherals should not have write access to program load memory regions.

Real-World CVE Examples

Related Weaknesses