Released Date 09/23/2003 TITLE ===== TCLHttpd 3.4.2 - Multiple Vulnerabilities DESCRIPTION =========== "TclHttpd is used both as a general-purpose Web server, and as a framework for building server applications. It implements Tcl (http://www.tcl.tk), including the Tcl Resource Center and Scriptics' electronic commerce facilities. It is also built into several commercial applications such as license servers and mail spam filters. Instructions for setting up the TclHttpd on your platform are given towards the end of the chapter, on page See The TclHttpd Distribution. It works on Unix, Windows, and Macintosh. You can have the server up and running quickly." More information at http://www.tcl.tk/software/tclhttpd/ PROBLEMS ======== Affected Version : TCLHttpd 3.4.2 (latest) and probably older builds Tested Platform : Linux(x86) Mutiple flaws in TCLHttpd server which open door for an attacker to browse any directories on the remote host, and to inject malicious javascript/vbscript content to the user's browser under the TCLHttpd server context (Cross Site Scripting). DETAILS ======= [Vulnerability #1] Arbitrary Directory Browsing When a user requests a directory on TCLHttpd server, httpdthread.tcl will start to look for various default index file names in that directory, if none can be found then it will pass the operation to dirlist.tcl script to do the "fancy" directory listing which provides users the ability to sort files by modify date, name, size or file's pattern. Dirlist.tcl script does filter inputs from the users in order to prevent directory traversal but it can be easily bypassed if an absolute path was entered. Directory listing is enabled by default. For example: Requesting http://abc.com/images/?pattern=/*&sort=name will return you a list of directory under / [Vulnerability #2] Cross Site Scripting (XSS) TCLHttpd web server comes with various modules in order to increase the flexibility of the server, and /debug module is enable by default which allows you to download logging information, debug the Tcl part of the application without restarting the hosting application. Many modules are suffered from the multiple Cross Site Scripting (XSS) vulnerabilities that potentially enable a malicious user to "inject" code into a user's session under TCLHttpd server context. I'm going to use the /debug module as an example. http://www.abc.com/debug/echo?name= http://www.abc.com/debug/dbg?host= http://www.abc.com/debug/showproc?proc= http://www.abc.com/debug/errorInfo?title= WORK AROUND =========== You can eliminate the threats from these vulnerabilities by editing your httpdthread.tcl and comment out the directory listing option, also you should disable the folowwing modules to prevent Cross Site Scripting: Status, Debug, Mail and Admin. Notes: Disabling some modules in your TCLhttpd configuration might decrease the flexibility of your server. VENDOR STATUS ============= Vendor has been notified. Phuong Nguyen