why do hackers love strings?
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- เผยแพร่เมื่อ 1 พ.ย. 2022
- Hackers have been trying to steal information since the beginning of the information age. Buffer overflow attacks have been one of the ways they do it. By taking advantage of logic bugs in programs, hackers have been able to get access to computers and steal information which they later sell on the dark web. Buffer overflows have been one of the most common ways they get in.
In C, strings are a little weird. Because there is no length encoded with the string type, string functions in C are extremely easy to use incorrectly. When used in an unsafe way, hackers can abuse the way that functions call each other to give them access to your computer.
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Be really fun to see your 'secure' server broken live and record the actual memory. Great video!
In this reality some hackers love strings more than physicists.
Technically you must read at most 63 bytes/characters. The 64th byte in the array is the null byte. And you need to remember to set it to null when creating the array.
And all this just because someone decided that extra few bytes for storing the length is too expensive.
You can always implement strings as structs and store the length data. It's C, you can do anything. Unfortunately, you still need to get the data back out pretty frequently as the usual null terminated char arrays in order to use other functions.
Honestly there are no excuses for buffer overflows in your programs today. With all the tools available to devs you have no reason for this to still happen.
I think you should make a course on how to program in C securely/safely for beginners.
We should all be grateful that code is getting safter
As a C programmer I would never uses gets() in a professional program. I always bound check when copying to buffers.
I have to say this channel is very, very, very good. You really are delivering quality wise.
Remember to pass the -fno-stack-protector flag when compiling your C programs for added stack based security.
4:59
That's why the newer secure versions of these input functions also include a max data value so they can ignore any input over the intended amount making them much more difficult to exploit with buffer over flows.
In Pascal-style strings, the length is encoded as a byte at string[0], or sometimes the first 2 bytes (first 2 indices). This is a practice that the Macintosh pre-Intel era used in its API, and how strings are usually stored in binary file formats.
It was informative!
Having just completed my CompTIA Network+, Security+ & PenTest+, this is a perfect example of the need for sanitisation of user input!!! Great video and you’ve just got a new subscriber!!
great video ! how did you get the function description in c
I am so glad your videos are short. Theyre so good.
This is great! I wish I had this years ago when I was learning more about Buffer Overflows for a pentesting cert. It took me like a year to actually perform my first BO but it was still messed up but it worked lol.