COMMON WEAKNESS ENUMERATIONDraft

CWE-395

Use of NullPointerException Catch to Detect NULL Pointer Dereference

Catching NullPointerException should not be used as an alternative to programmatic checks to prevent dereferencing a null pointer.

Abstraction

Base

Structure

Simple

Likelihood of Exploit

Medium

Understand the problem

What is the problem?

Catching NullPointerException should not be used as an alternative to programmatic checks to prevent dereferencing a null pointer.

Extended description

Programmers typically catch NullPointerException under three circumstances: - The program contains a null pointer dereference. Catching the resulting exception was easier than fixing the underlying problem. - The program explicitly throws a NullPointerException to signal an error condition. - The code is part of a test harness that supplies unexpected input to the classes under test. Of these three circumstances, only the last is acceptable.

Root cause

How and when does the problem arise?

Lifecycle phase

Implementation

Risk

What does successful exploitation lead to?

DoS: Resource Consumption (CPU)

Affected security scopes: Availability

Defence

How is it prevented and fixed?

Architecture and Design · Implementation

Defence to apply across several lifecycle phases

Detail
Do not extensively rely on catching exceptions (especially for validating user input) to handle errors. Handling exceptions can decrease the performance of an application.

Verification

How is it detected?

Automated Static Analysis - Binary or Bytecode

SOAR Partial
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Bytecode Weakness Analysis - including disassembler + source code weakness analysis Binary Weakness Analysis - including disassembler + source code weakness analysis

Dynamic Analysis with Manual Results Interpretation

SOAR Partial
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Framework-based Fuzzer

Manual Static Analysis - Source Code

SOAR Partial
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Manual Source Code Review (not inspections)

Automated Static Analysis - Source Code

High
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Source code Weakness Analyzer Context-configured Source Code Weakness Analyzer

Architecture or Design Review

High
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Formal Methods / Correct-By-Construction ``` Cost effective for partial coverage: ``` Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)