CWE-1209: Failure to Disable Reserved Bits | Glexia
CWE-1209 (Failure to Disable Reserved Bits) weakness overview with consequences, detection methods, mitigations, related CVEs and MITRE ATT&CK context.
Glexia's Take · Automated analysis
CWE-1209: Failure to Disable Reserved Bits
Failure to Disable Reserved Bits represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Executive Impact
- Confidentiality,Integrity,Availability,Access Control,Accountability,Authentication,Authorization,Non-Repudiation: Varies by Context: This type of weakness all depends on the capabilities of the logic being controlled or configured by the reserved bits.
Developer Pattern
CWE-1209 is the kind of defect developers can usually prevent with explicit validation, safer framework defaults, and tests that exercise hostile input or unsafe state transitions.
Automation confidence
high confidence from CWE-1209, 4.20.
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Official CWE Definition
CWE-1209: Failure to Disable Reserved Bits
The reserved bits in a hardware design are not disabled prior to production. Typically, reserved bits are used for future capabilities and should not support any functional logic in the design. However, designers might covertly use these bits to debug or further develop new capabilities in production hardware. Adversaries with access to these bits will write to them in hopes of compromising hardware state.
Developer And Remediation Guidance
How teams prevent and detect this weakness
Causes
- Assume a hardware Intellectual Property (IP) has address space 0x0-0x0F for its configuration registers, with the last one labeled reserved (i.e. 0x0F). Therefore inside the Finite State Machine (FSM), the code is as follows:
Remediation
- Architecture and Design,Implementation:
- Integration:
Detection
- Code review
- SAST
- DAST
- Focused regression tests
Mappings
Related CVEs, CWEs, and ATT&CK context
Related CWEs
ATT&CK Relevance
ATT&CK relevance is shown only when reviewed or responsibly inferred.