Hardware Internal or Debug Modes Allow Override of Locks

Opis

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.

Skutki

• Access Control

  Bypass Protection Mechanism

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

Zapobieganie

• 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.

  Skuteczność: High

Słabość nadrzędna

• CWE-667 Improper Locking

Kiedy powstaje

• Architecture and Design
• Implementation

Dotyczy

Not Language-Specific, Not OS-Specific, Not Architecture-Specific, Not Technology-Specific

Źródła

1. reglk_wrapper.sv — 2021
2. Fix for reglk_wrapper.sv — 2021