CWE-1231 Improper Prevention of Lock Bit Modification

The product uses a trusted lock bit for restricting access to registers, address regions, or other resources, but the product does not prevent the value of the lock bit from being modified after it has been set.

• Access Control: Modify Memory — Design or coding errors in the implementation of the lock bit protection feature may allow the lock bit to be modified or cleared by software after it has been set. Attackers might be able to unlock the system and features that the bit is intended to protect. Registers protected by tje lock bit can be modified even when the lock is set.

• [Architecture and Design, Implementation, Testing] • 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.

• Manual Analysis: Set the lock bit. Power cycle the device. Attempt to clear the lock bit. If the information is changed, implement a design fix. Retest. Also, attempt to indirectly clear the lock bit or bypass it.

• CVE-2017-6283: chip reset clears critical read/write lock permissions for RSA function