[NEWS] TCLHttpd Contains Two Vulnerabilities (Directory Browsing, XSS)

From: SecuriTeam (support_at_securiteam.com)
Date: 10/01/03

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    Date: 1 Oct 2003 11:49:29 +0200

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      TCLHttpd Contains Two Vulnerabilities (Directory Browsing, XSS)


     <http://www.tcl.tk/software/tclhttpd> 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".

    The product has been found to contain two security vulnerabilities that
    would allow a remote attacker to view the directory and file contents of
    directories residing on the server, and to cause the product to return
    arbitrary content as if it were its own.


    Vulnerable systems:
     * TCLHttpd version 3.4.2

    Multiple 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).

    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 /

    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. Phuong is going to use the /debug module as
    an example.


    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 following 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.


    The information has been provided by <mailto:dphuong@yahoo.com> Phuong


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