What is Heap Buffer Overflow Vulnerability?

IT Administrators managing Chrome updates in 2022 had a rough year. Several heap buffer overflow issues related to WebRTC in Google Chrome (especially around CVE-2022-2294) meant that IT teams were busy trying to stay on top of securing their highest-risk, and frequently used, applications. 

Assuming Google Chrome or Chromium-based web browsers are part of your endpoint infrastructure in 2023 and beyond, it’s prudent to understand how heap buffer overflow vulnerabilities work and how to actively plan for mitigating these overflow occurrences should they arise.

Heap is a section of memory that stores dynamic variables. Consider the memory available for your software development needs as a pool or ‘heap’ of memory segments. Modern software systems dynamically allocate, manage, and release data and variables by pointing to and using a finite amount of these memory segments. 

There might occur instances when the inputs passed using these software elements might be too large and run over these finitely assigned memory blocks and might ‘overflow’ into adjacent memory blocks, inadvertently accessing the information in those segments. 

Attackers looking to access critical data in these segments can take control of this heap overflow vulnerability and allow it to be turned into arbitrary code execution, for example, by tricking a user into visiting a specially crafted HTML page in Chrome. These bad actors can use heap-based overflows to overwrite pointers or object metadata that may be living in memory, pointing it to the attacker's code.

While you may argue that most modern software programming languages can abstract and manage memory allocation efficiently, the runtime environments for some languages might be on a low-level programming language like C, potentially leaving the door open for inefficient heap management.

Heap buffer overflows can commonly occur in large software development cycles if thorough testing of providing user inputs without sufficient validation does not take place. 

Such overflow vulnerability occurrences might make it look similar to stack based buffer overflows, except that finding and triggering heap buffer overflows require much more diligence in understanding memory allocation patterns in a code base. With enough sophistication, hackers can gain access and execute custom code, giving them access to any process running on that endpoint. 

Since such overflows can go undetected, especially in OS-level implementations (like iOS or Windows) or large software (like Google Chrome), exploiting a vulnerability such as this can give attackers a massive global-level attack surface to impact millions of endpoints. 

So how can your IT team thwart such sophisticated attacks and shield your endpoints? Use the following best practices below as a starting point to circumvent heap buffer overflow attacks.

Your team might be unable to completely stop bad actors from attacking your IT infrastructure. Still, you can hold them back by deploying strong access policies and multi-factor authentication to discourage their rigor in finding a way into your organization’s environment.

Testing complex software systems like browser updates can be overwhelming. Deploying a mix of excellent heap memory debugging tools (like GNU libc) and a comprehensive set of development standards for sanity checks and address randomization (like ASLR) can set your development teams up for securing their code from heap buffer overflows.

The best way to stay ahead of attackers looking to exploit heap buffer overflow vulnerabilities would be to ensure the latest patches are deployed as they become available. If you have a large endpoint footprint, automating the patching and updating process can save your IT team a lot of time, resources, and heartburn in ensuring that your IT infrastructure gets a fighting chance to stay on top of such vulnerabilities.