COMMON WEAKNESS ENUMERATIONDraft

CWE-394

Unexpected Status Code or Return Value

The product does not properly check when a function or operation returns a value that is legitimate for the function, but is not expected by the product.

Abstraction

Base

Structure

Simple

Likelihood of Exploit

Medium

Understand the problem

What is the problem?

The product does not properly check when a function or operation returns a value that is legitimate for the function, but is not expected by the product.

Root cause

How and when does the problem arise?

Lifecycle phase

Implementation

Risk

What does successful exploitation lead to?

Unexpected StateAlter Execution Logic

Affected security scopes: Integrity, Other

Defence

How is it prevented and fixed?

  • Follow secure coding guidelines for input handling and boundary checking.
  • Enforce strict security reviews and automated static analysis (SAST) checks.

Verification

How is it detected?

Automated Static Analysis

High
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.)