CWE-783 Detail

The product uses an expression in which operator precedence causes incorrect logic to be used.

While often just a bug, operator precedence logic errors can have serious consequences if they are used in security-critical code, such as making an authentication decision.

Modes Of Introduction

Implementation : Logic errors related to operator precedence may cause problems even during normal operation, so they are probably discovered quickly during the testing phase. If testing is incomplete or there is a strong reliance on manual review of the code, then these errors may not be discovered before the software is deployed.

Applicable Platforms

Language

Name: C (Rarely)
Name: C++ (Rarely)
Class: Not Language-Specific (Rarely)

Common Consequences

Observed Examples

Potential Mitigations

Phases : Implementation
Regularly wrap sub-expressions in parentheses, especially in security-critical code.

Detection Methods

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.)
Effectiveness : High

Vulnerability Mapping Notes

Justification : This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Comment : Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

References

REF-704

EXP00-C. Use parentheses for precedence of operation
CERT.
https://www.securecoding.cert.org/confluence/display/seccode/EXP00-C.+Use+parentheses+for+precedence+of+operation

REF-62

The Art of Software Security Assessment
Mark Dowd, John McDonald, Justin Schuh.

Submission

Modifications