Exploiting Off By One Vulnerabilities

On this stream/vid, we'll take a look at some basic off by one vulnerabilities and how you can turn a one-byte overwrite into code execution. If you've exploited buffer overflow vulnerabilities then you are probably used to seeing the registers holding values such as 0x41414141, indicating that your data has somehow ended up where it's not supposed to be. With Off By One vulnerabilities it's a bit different. You often are only able to overwrite a single byte out of bounds. Interestingly, under the right conditions, this can be enough to result in code execution, when combined with taking advantage of interesting hooks, such as those related to the functions free and malloc.

[@jacob-ty4vr]

never stop doing this videos😊

[@Janek-eh2en]

The best security content

[@patricksako887]

Really grateful for these videos Stephen

[@morganguesdon2202]

As always, amazing content and amazing explanations

[@danielsalloum3006]

Very well explained. I almost feel capable.

[@OffByOneSecurity]

Just keep at it and you'll get there, and then onto the next challenge!

[@jasoncornell3800]

❤

[@rodneynsubuga6275]

The off by one can article 55 of phrack be an example

[@OffByOneSecurity]

when I look that up I get a result from 1999. Can you elaborate?

[@rodneynsubuga6275]

Like it ways also showing a use case of an offbyone but stack based; though it would only work on x32 as u said in the video