Buffer overflow attacks continue to be a problem.
July 8, 2019

What is Buffer Overflow? How to Prevent Buffer Overflow?

Security & Compliance
Static Analysis

Coding mistakes are the most common cause of software vulnerabilities — such as buffer overflow. If a developer doesn't catch a vulnerability or error in their code, that weakness could lead to a cyberattack. For that reason, it is important to understand what is buffer overflow, how to prevent buffer overflow and buffer overflow attack, and provide buffer overflow examples.

What Is Buffer Overflow?

A buffer overflow is a common software vulnerability. Also known as a buffer overrun, this software security issue is serious because it exposes systems to potential cyberthreats and cyberattacks.

Buffer overflow happens when there is excess data in a buffer which causes the “overflow”. The extra data then overruns into adjacent storage. When this type of security issue occurs, it can cause a full system crash. 

Buffer Overflow Examples

There are several different ways that the software vulnerability may occur within your code. Klocwork has an extensive set of buffer overflow checkers to help ensure that the vulnerabilities cannot be exploited. Each checker provides a description of the violation, an explanation of the potential vulnerabilities and risks, and an example of the code.

You can view the complete list of buffer overflow violation examples here.

How to Prevent Buffer Overflow?

One way to completely prevent cyberattacks is to use a coding language that doesn’t allow for them. For example, C is a primary target for buffer attacks because the language enables the vulnerability through direct access to memory.  On the other hand, languages like Java, Python, and .NET, are immune to buffer vulnerabilities. 

Another way to prevent the software vulnerability is to be aware of buffer usage during development. Where buffers are accessed is where the vulnerabilities will occur, especially if the functions deal with user-generated input.  

In addition, here are five best practices for preventing buffer overflow: 

1. Leveraging automated code review and testing.

2. DevOps training on the concepts of using unsafe functions. 

3. A focus on safe functions like strncpy vs strcpy  and strncat vs strcat.

4. Keeping application servers patched. 

5. Using code analysis tools to periodically check applications for software security flaws.

Why Source Code Analysis is the Best Solution for a Buffer Overflow Attack

To absolutely ensure your application is safe from damaging software vulnerabilities attacks, the best course of action is to use static code analysis (SCA). As mentioned, C and C++ are particularly vulnerable to overflow. To protect C and C++ applications, DevOps can use a SCA tool and run a compliance taxonomy like MISRA or CERT to identify software vulnerabilities.  

Static application security testing (SAST)tools are important for detecting security vulnerabilities across software applications.  With SCA tools, security vulnerability issues can be found as code is being developed.  

If your organization wants proactive protection against security threats, a static code analysis tool like Klocwork can help.

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