APSI
APSI EN 1
APSI EN 1
Kartei Details
| Karten | 10 |
|---|---|
| Sprache | Deutsch |
| Kategorie | Informatik |
| Stufe | Universität |
| Erstellt / Aktualisiert | 19.11.2021 / 19.11.2021 |
| Lizenzierung | Keine Angabe |
| Weblink |
https://card2brain.ch/box/20211119_apsi
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| Einbinden |
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What is a bufferoverflow attack?
Copying more data in a buffer than it can handle
What is the purpose of the following code?
#include <string.h>
#include <stdio.h>
int main (int argc, char *argv[]) {
char s2[4] = "yes"; // set s2 to "yes"
char s1[4] = "abc"; // set s1 to "abc"
strcpy(s1, argv[1]); // copy argv[1] into s1
puts(s2); // print s2
}
To overflow the char array s1 with the programm arguments and overwrite the char array s2.
What naiv approach can be used to secure against bufferoverflows and when does it apply?
A Stack Protection can be implemented. The idea is to place random values on the stack and then verify it. It is usually done to protect the return address of a function:
Stack: <local vars><random value><return address>
What are the problems with Stack Protection?
- Where can it be placed?
- When should it be checked?
- Causes extra effort.
- Does not protect buffer-overflow on the heap
