CWE-768 Incorrect Short Circuit Evaluation

The product contains a conditional statement with multiple logical expressions in which one of the non-leading expressions may produce side effects.

If the first condition of an "or" statement is assumed to be true under normal circumstances, or if the first condition of an "and" statement is assumed to be false, then any subsequent conditional may contain its own logic errors that are not detected during code review or testing.

• Confidentiality, Integrity, Availability: Varies by Context — Widely varied consequences are possible if an attacker is aware of an unexpected state in the product after a conditional. Usage of short circuit evaluation, though well-defined in the C standard, may alter control flow in a way that introduces logic errors that are difficult to detect, possibly causing errors later during the product's execution. It may lead to information exposure, a system crash, or even complete attacker control of the system. • Other: Unexpected State — This may lead to an unexpected state in the program after the execution of the conditional, because short-circuiting logic may prevent the side effects from occurring. • Other: Reduce Maintainability — The usage of short circuit evaluation may decrease the maintainability of the code.

• [Implementation] Minimizing the number of statements in a conditional that produce side effects will help to prevent the likelihood of short circuit evaluation to alter control flow in an unexpected way.

• Automated Static Analysis: Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)