Sensitive Information Uncleared Before Debug/Power State Transition

Sensitive information may leak as a result of a debug or power state transition when information access restrictions change as a result of the transition.


Description

A device or system frequently employs many power and sleep states during its normal operation (e.g., normal power, additional power, low power, hibernate, deep sleep, etc.). A device also may be operating within a debug condition. State transitions can happen from one power or debug state to another. 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 make leak from the system.

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

This example shows how an attacker can take advantage of an incorrect state transition.

Suppose a device is transitioning from state A to state B. During state A, it can read certain private keys from the hidden fuses that are only accessible in state A but not in state B. The device reads the keys, performs operations using those keys, then transitions to state B where those private keys should no longer be accessible.However, during this transition, the device does not scrub the memory. After the transition to state B, even though the private keys are no longer accessible directly from the fuses in state B, they can be accessed indirectly by reading the memory which contains the private keys.
For transition from state A to state B remove information which should not be available once the transition is complete.

See Also

Debug and Test Problems

Weaknesses in this category are related to hardware debug and test interfaces such as JTAG and scan chain.

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 Design

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


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