Description
The address map of the on-chip fabric has protected and unprotected regions overlapping, allowing an attacker to bypass access control to the overlapping portion of the protected region.
Modes of Introduction:
– Architecture and Design
Related Weaknesses
CWE-284
Consequences
Confidentiality, Integrity, Access Control, Authorization: Bypass Protection Mechanism, Read Memory, Modify Memory
Potential Mitigations
Phase: Architecture and Design
Description:
When architecting the address map of the chip, ensure that protected and unprotected ranges are isolated and do not overlap. When designing, ensure that ranges hardcoded in Register-Transfer Level (RTL) do not overlap.
Phase: Implementation
Description:
Ranges configured by firmware should not overlap. If overlaps are mandatory because of constraints such as a limited number of registers, then ensure that no assets are present in the overlapped portion.
Phase: Testing
Description:
Validate mitigation actions with robust testing.
CVE References
- CVE-2009-4419
- Attacker can modify MCHBAR register to overlap with an attacker-controlled region, which modification prevents the SENTER instruction from properly applying VT-d protection while a Measured Launch Environment is being launched.
