Exploitability depends more on how much control you have on the application, and there is no silver bullet on the OS level like in previous years.Ĭlient-side applications (such as a browser, PDF, Flash, etc.) tend to be excellent targets due to the support of scripting languages. A modern system is really good at protecting its heaps nowadays, and every time you see this function call is pretty much a sign that you have been defeated. In a debugger, you will be presented with an error of 0xc0000374, indicating a heap corruption exception that is due to a failed inspection on the heap, resulting in a call to RtlpLogHeapFailure. Clearly, it is trying to pass a size of 64 bytes to a smaller heap buffer that is only 32 bytes. This is a basic example of a heap overflow.
Since heap corruption is such a scary topic, let's start with a heap overflow on Windows 10.
One way that guarantees I will learn about a vulnerability is by figuring out how to create it and mess with it. If the developers didn't spend just a few days building the codebase, there certainly isn't any magic to absorb so much internal knowledge about it in such a short amount of time. Often, you may get away with examining a good crash, get EIP, add some shellcode, and get a working exploit, but you may not fully understand the actual problem as quickly. Learning a vulnerability from a real application can be difficult because the codebase may be complex. By doing so, you encourage the community to engage on the topic, and one day, someone is going to advance and share something new in return. Being a former Corelan member, I know that some of the best exploit tutorials from Corelan started off this way, with Peter Van Eeckhoutte and his team researching the topic, documenting the process, and in the end, sharing that with the public. People may get a grasp of the theory, it still remains a scary topic, and they still don't even know where to start.Īs LiveOverflow points out, there is a lot of value in explaining how you mastered something, more than just publishing an exploit. Although a Black Hat talk may follow explaining that, those talks are probably overwhelming for the most part. About every couple of years, some major security improvement would be introduced, likely terminating a vulnerability class or an exploitation technique. My impression is that many people certainly feel this way about heap corruptions, which are indeed difficult because they are unpredictable in nature, and the mitigations are always evolving. It's just a scary topic, and I don't even know where to start. LiveOverflow, who is most well known for his hacking videos on YouTube, shares the same feeling about approaching browser exploitation in the early stage, saying: And I don't think I'm the only person to feel this way. However, memory corruption for me is still quite a challenge, despite having a soft spot for it. More than 10 years later, I have some memory corruption exploits under my belt, from small-third-party applications to high-profile products such as Microsoft, Adobe, Oracle, Mozilla, and IBM.
It wasn't until months later that I tried a different example on the internet and finally popped a shell. It was a stack buffer overflow example I tried to follow in this book called “ Hacking: The Art of Exploitation.” I fought for weeks, and I failed. I remember the first time I attempted to exploit a memory corruption vulnerability.