CWE-1071: Empty Code Block

Description

The source code contains a block that does not contain any code, i.e., the block is empty.

Empty code blocks can occur in the bodies of conditionals, function or method definitions, exception handlers, etc. While an empty code block might be intentional, it might also indicate incomplete implementation, accidental code deletion, unexpected macro expansion, etc. For some programming languages and constructs, an empty block might be allowed by the syntax, but the lack of any behavior within the block might violate a convention or API in such a way that it is an error.

Potential Impact

Other

Reduce Reliability

Demonstrative Examples

In the following Java example, the code catches an ArithmeticException.

Bad

public class Main {
                     public static void main(String[] args) {
                        int a = 1;
                        int b = 0;
                        int c = 0;
                        try {
                           c = a / b;
                        } catch(ArithmeticException ae) {
                        }
                     }
                  }

Since the exception block is empty, no action is taken.

In the code below the exception has been logged and the bad execution has been handled in the desired way allowing the program to continue in an expected way.

Good

public class Main {
                     public static void main(String[] args) {
                        int a = 1;
                        int b = 0;
                        int c = 0;
                        try {
                           c = a / b;
                        } catch(ArithmeticException ae) {
                           log.error("Divided by zero detected, setting to -1.");
                           c = -1;
                        }
                     }
                  }

The following code attempts to synchronize on an object, but does not execute anything in the synchronized block. This does not actually accomplish anything and may be a sign that a programmer is wrestling with synchronization but has not yet achieved the result they intend.

Bad

synchronized(this) { }

Instead, in a correct usage, the synchronized statement should contain procedures that access or modify data that is exposed to multiple threads. For example, consider a scenario in which several threads are accessing student records at the same time. The method which sets the student ID to a new value will need to make sure that nobody else is accessing this data at the same time and will require synchronization.

Good

public void setID(int ID){synchronized(this){this.ID = ID;}}

Detection Methods

Automated Static Analysis High — 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 sea

Frequently Asked Questions

What is CWE-1071?

CWE-1071 (Empty Code Block) is a software weakness identified by MITRE's Common Weakness Enumeration. It is classified as a Base-level weakness. The source code contains a block that does not contain any code, i.e., the block is empty.

How can CWE-1071 be exploited?

Attackers can exploit CWE-1071 (Empty Code Block) to reduce reliability. This weakness is typically introduced during the Implementation phase of software development.

How do I prevent CWE-1071?

Follow secure coding practices, conduct code reviews, and use automated security testing tools (SAST/DAST) to detect this weakness early in the development lifecycle.

What is the severity of CWE-1071?

CWE-1071 is classified as a Base-level weakness (Medium abstraction). Its actual severity depends on the specific context and how the weakness manifests in your application.