CWE-1234

Base Abstraction Level
Pillar — Highest-level weakness category
Class — Abstract, language-independent
Base — Specific enough to detect
Variant — Tied to specific technology
Compound — Requires multiple weaknesses Incomplete MITRE CWE Status
Stable — Fully reviewed and complete
Draft — Under development, may change
Incomplete — Partially defined by MITRE
Deprecated — No longer recommended
Obsolete — Replaced by another CWE
Hardware Internal or Debug Modes Allow Override of Locks

Description

System configuration protection may be bypassed during debug mode.

Device configuration controls are commonly programmed after a device power reset by a trusted firmware or software module (e.g., BIOS/bootloader) and then locked from any further modification. This is commonly implemented using a trusted lock bit, which when set, disables 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). If debug features supported by hardware or internal modes/system states are supported in the hardware design, modification of the lock protection may be allowed allowing access and modification of configuration information.

Consequences

Access Control — Bypass Protection Mechanism

Bypass of lock bit allows access and modification of system configuration even when the lock bit is set.

Mitigations

Phase: Architecture and Design, Implementation, Testing

Security Lock bit protections should be reviewed for any bypass/override modes supported. Any supported override modes either should be removed or protected using authenticated debug modes. Security lock programming flow and lock properties should be tested in pre-silicon and post-silicon testing.