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Understand buffer overflows

Understand buffer overflows - Linux Tutorial

From the course: Penetration Testing Essential Training

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Understand buffer overflows

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- [Person] There are a number of ways to achieve remote code execution on a server, and one of the ways is to trigger what's known as a buffer overflow. We can do this by sending a malicious exploit packet to an open service that has a buffer overflow vulnerability. This then results in the target executing code from our packet. We can see how this works by running a vulnerable program through a debugger. Let's do this with MASM so that we can see the instructions clearly. I've written a small MASM program, which uses the Windows GUI, called "buffalo.asm." This simulates just a fragment of an application. Take a look at the lines just below the ".data" declaration. There's a data field called "Packet." This is simulating a packet that we've received from an input request for the user's name. I've put my name there. Let's just ignore the commented-out fields for the moment. Further down, we can see the hello message, which expects to have a name inserted. Let's look at the lines just…

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