Xitami Denial of Service in Handling malformed request ================================================= PROGRAM: Xitami HOMEPAGE: http://www.xitami.com VULNERABLE VERSIONS: 2.5 and below DESCRIPTION ================================================= LiteServe is a very powerful, full-featured, open-sourced Web server. and the flagship of iMatix. This is a great free product. DETAILS ================================================= Xitami has a logical error in the way it handles POST request that can be used to perform a Denial-of-service attack. An Request like this will make the server won't response to any other requests although it is still listen to port 80 POST /forum/index.php HTTP/1.1 Referer: Sentryunion Accept-Encoding: None User-Agent: Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0) Content-Length: 10 (long string here) 0x0D 0x0A (another long string here) Xitami is a very good server. However the code to handle parsing the HTTP header doesn't have a good logic: while(header && *header && *header != '\r') { header_name = header if((header_value=strchr(header_name, ":")) != NULL) { ... header++;} } So if inside the request HTTP header there is no ":" charater. It will make the while loop runs forever = Denial of Service. WORKAROUND ================================================= Use URL filter to filter all the bad request. Vendor doesn't response after 2 weeks ! CREDITS ================================================= Discovered by Tri Huynh from Sentry Union DISLAIMER ================================================= The information within this paper may change without notice. Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties with regard to this information. In no event shall the author be liable for any damages whatsoever arising out of or in connection with the use or spread of this information. Any use of this information is at the user's own risk. FEEDBACK ================================================= Please send suggestions, updates, and comments to: trihuynh@zeeup.com