Improper Access Control for Volatile Memory Containing Boot Code
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.
Description
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.
If the volatile-memory-region protections or access controls are insufficient to prevent modifications from an adversary or untrusted agent, the secure boot may be bypassed or replaced with the execution of an adversary's code.
Demonstrations
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 typical SoC secure boot's flow includes fetching the next piece of code (i.e., the boot loader) from NVM (e.g., serial, peripheral interface (SPI) flash), and transferring it to DRAM/SRAM volatile, internal memory, which is more efficient.
The volatile-memory protections or access controls are insufficient.The memory from where the boot loader executes can be modified by an adversary.
A good architecture should define appropriate protections or access controls to prevent modification by an adversary or untrusted agent, once the bootloader is authenticated.See Also
Weaknesses in this category are related to access control.
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 ...
This view (slice) covers all the elements in CWE.
CWE entries in this view are listed in the 2021 CWE Most Important Hardware Weaknesses List, as determined by the Hardware CWE Special Interest Group (HW CWE SIG).
This view (slice) lists weaknesses that can be introduced during design.
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