Register Interface Allows Software Access to Sensitive Data or Security Settings

Memory-mapped registers provide access to hardware functionality from software and if not properly secured can result in loss of confidentiality and integrity.


Description

Software commonly accesses peripherals in an SoC through a memory-mapped register interface. Any security-critical data accessible directly or indirectly through the register interface must have a clearly defined and correctly implemented access control policy to protect assets from malicious software tampering.

Demonstrations

The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

The register interface provides software access to hardware functionality. This functionality is an attack surface. This attack surface may be used to run untrusted code on the system through the register interface. As an example, cryptographic accelerators require a mechanism for software to select modes of operation and to provide plaintext or ciphertext data to be encrypted or decrypted as well as other functions. This functionality is commonly provided through registers.

Cryptographic key material stored in registers inside the cryptographic accelerator can be accessed by software.
Key material stored in registers should never be accessible to software. Even if software can provide a key, all read-back paths to software should be disabled.

See Also

Privilege Separation and Access Control Issues

Weaknesses in this category are related to features and mechanisms providing hardware-based isolation and access control (e.g., identity, policy, locking control) of s...

Comprehensive CWE Dictionary

This view (slice) covers all the elements in CWE.

Weaknesses without Software Fault Patterns

CWE identifiers in this view are weaknesses that do not have associated Software Fault Patterns (SFPs), as covered by the CWE-888 view. As such, they represent gaps in...

Weaknesses Introduced During Implementation

This view (slice) lists weaknesses that can be introduced during implementation.


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