Weakness · Medium
CWE-395: Use of NullPointerException Catch to Detect NULL Pointer Dereference
What it is
Catching NullPointerException should not be used as an alternative to programmatic checks to prevent dereferencing a null pointer.
- Severity (our rating)
- Medium
- Likelihood of exploit
- Not rated by MITRE
- Introduced during
- Implementation
- Exploited in the wild
- No CVE in CISA's catalog
In more detail
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.
What an attacker can do
- DoS: Resource Consumption (CPU) (Availability)
How to prevent it
Architecture and Design
- Do not extensively rely on catching exceptions (especially for validating user input) to handle errors. Handling exceptions can decrease the performance of an application.
How to find it
- Automated Static Analysis - Binary or Bytecode. According to SOAR, 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. According to SOAR, the following detection techniques may be useful: Cost effective for partial coverage: Framework-based Fuzzer
- Manual Static Analysis - Source Code. According to SOAR, the following detection techniques may be useful: Cost effective for partial coverage: Manual Source Code Review (not inspections)
- Automated Static Analysis - Source Code. According to SOAR, the following detection techniques may be useful: Highly cost effective: Source code Weakness Analyzer Context-configured Source Code Weakness Analyzer
- Architecture or Design Review. According to SOAR, 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.)
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Start freeSource: MITRE Common Weakness Enumeration, CWE version 4.19.1. CWE is a trademark of The MITRE Corporation.