Buffer overflow (off by 1) exploit

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This video demonstrates how to exploit a program where the buffer can be overflowed by one.

Compilation line:
gcc -fno-stack-protector -m32 -mpreferred-stack-boundary=2 -z execstack -o offby offby.c
Note that '-mpreferred-stack-boundary=2' is used to ensure that the esp occurs directly after the buffer. Without this program is likely not exploitable on most linux distributions

NOTE: If this tutorial is not working it is likely that you have aslr enabled. To disable it run the following command in your terminal
echo 0 | sudo tee /proc/sys/kernel/randomize_va_space
When you are finished I strongly recommend you turn it back on with the command
echo 2 | sudo tee /proc/sys/kernel/randomize_va_space
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Why 100 of those return addresses and why did you change the start address of the buffer?

gudimetlakowshik
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so I can sort of the shell to spawn, but when i continue, it justs exits normally and says inferior.

kooners
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When I hit continue, it says that program is not being run.

kooners
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Hi, man, I had a question that you created a buffer size 1024, but cause a overflow by 'A'*1024. How could it be? It should be a normal execution?

BobSmith-shjq
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Plus I can't even perform a buffer overflow attack with A's.

kooners
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