CWE-595

Variant Abstraction Level
Pillar — Highest-level weakness category
Class — Abstract, language-independent
Base — Specific enough to detect
Variant — Tied to specific technology
Compound — Requires multiple weaknesses Incomplete MITRE CWE Status
Stable — Fully reviewed and complete
Draft — Under development, may change
Incomplete — Partially defined by MITRE
Deprecated — No longer recommended
Obsolete — Replaced by another CWE
Comparison of Object References Instead of Object Contents

Description

The product compares object references instead of the contents of the objects themselves, preventing it from detecting equivalent objects.

For example, in Java, comparing objects using == usually produces deceptive results, since the == operator compares object references rather than values; often, this means that using == for strings is actually comparing the strings' references, not their values.

Consequences

Other — Varies by Context

This weakness can lead to erroneous results that can cause unexpected application behaviors.

Mitigations

Phase: Implementation

In Java, use the equals() method to compare objects instead of the == operator. If using ==, it is important for performance reasons that your objects are created by a static factory, not by a constructor.

Detection

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.)