Weakness · Medium
CWE-1233: Security-Sensitive Hardware Controls with Missing Lock Bit Protection
What it is
The product uses a register lock bit protection mechanism, but it does not ensure that the lock bit prevents modification of system registers or controls that perform changes to important hardware system configuration.
- Severity (our rating)
- Medium
- Likelihood of exploit
- Not rated by MITRE
- Introduced during
- Architecture and Design, Implementation
- Exploited in the wild
- No CVE in CISA's catalog
In more detail
Integrated circuits and hardware intellectual properties (IPs) might provide device configuration controls that need to be programmed after device power reset by a trusted firmware or software module, commonly set by BIOS/bootloader. After reset, there can be an expectation that the controls cannot be used to perform any further modification. This behavior is commonly implemented using a trusted lock bit, which can be set to disable writes to a protected set of registers or address regions. The lock protection is intended to prevent modification of certain system configuration (e.g., memory/memory protection unit configuration). However, if the lock bit does not effectively write-protect all system registers or controls that could modify the protected system configuration, then an adversary may be able to use software to access the registers/controls and modify the protected hardware configuration.
What an attacker can do
- Modify Memory (Access Control)
How to prevent it
Architecture and Design
- Security lock bit protections must be reviewed for design inconsistency and common weaknesses. Security lock programming flow and lock properties must be tested in pre-silicon and post-silicon testing.
How to find it
- Manual Analysis. Set the lock bit. Attempt to modify the information protected by the lock bit. If the information is changed, implement a design fix. Retest. Also, attempt to indirectly clear the lock bit or bypass it.
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Start freeSource: MITRE Common Weakness Enumeration, CWE version 4.19.1. CWE is a trademark of The MITRE Corporation.