CWE-595: Comparison of Object References Instead of Object Contents
Official CWE-595 CWE context with Glexia analysis, remediation guidance, related CVEs, and ATT&CK context.
Glexia's Take
CWE-595: Comparison of Object References Instead of Object Contents
Comparison of Object References Instead of Object Contents represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Executive Impact
- Other: Varies by Context: This weakness can lead to erroneous results that can cause unexpected application behaviors.
Developer Pattern
CWE-595 is the kind of defect developers can usually prevent with explicit validation, safer framework defaults, and tests that exercise hostile input or unsafe state transitions.
Confidence
high confidence from CWE-595, 4.20.
Official CWE Definition
CWE-595: Comparison of Object References Instead of Object Contents
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.
Developer And Remediation Guidance
How teams prevent and detect this weakness
Causes
- In the example below, two Java String objects are declared and initialized with the same string values. An if statement is used to determine if the strings are equivalent. However, the if statement will not be executed as the strings are compared using the "==" operator. For Java objects, such as String objects, the "==" operator compares object references, not object values. While the two String objects above contain the same string values, they refer to different object references, so the System.out.println statement will not be executed. To compare object values, the previous code could be modified to use the equals method:
- In the following Java example, two BankAccount objects are compared in the isSameAccount method using the == operator. Using the == operator to compare objects may produce incorrect or deceptive results by comparing object references rather than values. The equals() method should be used to ensure correct results or objects should contain a member variable that uniquely identifies the object.,The following example shows the use of the equals() method to compare the BankAccount objects and the next example uses a class get method to retrieve the bank account number that uniquely identifies the BankAccount object to compare the objects.
Remediation
- 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.)
Mappings
Related CVEs, CWEs, and ATT&CK context
Related CWEs
ATT&CK Relevance
ATT&CK relevance is shown only when reviewed or responsibly inferred.