CWE-1272 Sensitive Information Uncleared Before Debug/Power State Transition

The product performs a power or debug state transition, but it does not clear sensitive information that should no longer be accessible due to changes to information access restrictions.

• Confidentiality, Integrity, Availability, Access Control, Accountability, Authentication, Authorization, Non-Repudiation: Read Memory, Read Application Data — If there is information available in the previous state which should not be available in the next state and is not properly removed before the transition into the next state, sensitive information may leak from the system. The sensitive information may be used to unlock additional capabilities of the device and take advantage of hidden functionalities which could be used to compromise device security.

• [Architecture and Design, Implementation] During state transitions, information not needed in the next state should be removed before the transition to the next state.

• Manual Analysis: Write a known pattern into each sensitive location. Enter the power/debug state in question. Read data back from the sensitive locations. If the reads are successful, and the data is the same as the pattern that was originally written, the test fails and the device needs to be fixed. Note that this test can likely be automated.

• CVE-2020-12926: Product software does not set a flag as per TPM specifications, thereby preventing a failed authorization attempt from being recorded after a loss of power.