Buffer Overflow

to escalate privileges or, (in linux words)

to gain root access.

But WHY?

compiled shellcode wannabe

low mem address

high mem address

buffer

return

How buffer overflow is exploited (stack version)

other stuff

pointing where it should

buffer

return

other stuff

pointing somewhere into our no operation slope

no operation

buffer overridden

memory  layout (simplified)

pointing where it should

Testing strategies

Boundary testing, by filling the buffer + return space with invalid addresses

Catch segmentation faults!

... we suggest prevention. Scan the code for vulnerable libc functions (e.g. strcpy)