CWE-495

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 Draft 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
Private Data Structure Returned From A Public Method

Description

The product has a method that is declared public, but returns a reference to a private data structure, which could then be modified in unexpected ways.

Consequences

Integrity — Modify Application Data

The contents of the data structure can be modified from outside the intended scope.

Mitigations

Phase: Implementation

Declare the method private.

Phase: Implementation

Clone the member data and keep an unmodified version of the data private to the object.

Phase: Implementation

Use public setter methods that govern how a private member can be modified.

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.)