Programming

17354 readers

548 users here now

Welcome to the main community in programming.dev! Feel free to post anything relating to programming here!

Cross posting is strongly encouraged in the instance. If you feel your post or another person's post makes sense in another community cross post into it.

Hope you enjoy the instance!

Rules

Follow the programming.dev instance rules
Keep content related to programming in some way
If you're posting long videos try to add in some form of tldr for those who don't want to watch videos

Wormhole

Follow the wormhole through a path of communities !webdev@programming.dev

founded 1 year ago

MODERATORS

snowe@programming.dev

Ategon@programming.dev

MaungaHikoi@lemmy.nz

Is there an example program that illustrates how a buffer overflow attack actually executes arbitrary code? (lemmy.dbzer0.com)

submitted 3 months ago* (last edited 3 months ago) by LainTrain@lemmy.dbzer0.com to c/programming@programming.dev

27 comments fedilink hide all child comments

I've found lots of examples in C of programs illustrating buffer Overflows, including those of pointer rewrites which has been of great help in understanding how a buffer overflow works and memory safety etc. but I've yet to be able to find an example illustrating how such a buffer overflow can rewrite a pointer in such a way that it actually results in code execution?

Is this just not a thing, or is my google-fu rust y? Tried ChatGPT and my local Mistral and they both seem unable to spit out precisely what I'm asking, so maybe I'm wording this question wrong.

If anyone in here knows, could point me in the right direction? Thanks y'all btw love this community 🧡

you are viewing a single comment's thread
view the rest of the comments

[–] LainTrain@lemmy.dbzer0.com 1 points 3 months ago (1 children)

Thank you! This is incredibly helpful and insightful.

I now understand how one would do this with manually writing in a debugger, am I correct in thinking that if I constructed the input to gets() in such a manner that BBBBBBB contains shellcode, and RRRR is a return address pointing to the beginning of BBBBB then that is how arbitrary code execution can be achieved with this in practice?

[–] sharky5740@techhub.social 1 points 3 months ago* (last edited 3 months ago) (1 children)

@LainTrain Yes, but "in practice" this simple approach worked 20 years ago. Modern processors, compilers and operating systems make exploitation of stack buffer overflows a lot more difficult.

[–] LainTrain@lemmy.dbzer0.com 1 points 3 months ago

That's fine, I think for my purposes it's better to start simple with the basic concept of it first, then add complexity by learning about the protections and how they have/could be circumvented.