CAPEC-680: Exploitation of Improperly Controlled Registers
An adversary exploits missing or incorrectly configured access control within registers to read/write data that is not meant to be obtained or modified by a user.
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Overview
Hardware systems often utilize trusted lock bits to prevent a set of registers from being written to or to restrict a register to only being written to once. Registers are also frequently used to store sensitive data leveraged in additional security operations, such as secure booting, authenticating code, device attestation, and more. However, the access control mechanisms meant to protect these registers may be fully missing or ineffective due to misconfiguration. If an adversary is able to discover improper access controls surrounding registers, it could result in the adversary obtaining sensitive data and/or modifying data that is meant to be immutable. This can ultimately result in processes like secure boot being circumvented or in protected configurations being modified.
What the attacker needs
Prerequisites
- Awareness of the hardware being leveraged.
- Access to the hardware being leveraged.
Skills required
- High skill: Intricate knowledge of registers.
Consequences
What a successful CAPEC-680 attack can achieve.
Modify Data
Affects: Integrity
Read Data
Affects: Confidentiality
How to mitigate it
Defenses that reduce the risk of CAPEC-680.
- Design proper access control policies for hardware register access from software and ensure these policies are implemented in accordance with the specified design.