Mort Bay Information for VU#402580

Jetty HTTP server directory traversal vulnerability



Vendor Statement

A security vulnerability has been discovered in jetty that effects

    all version of Jetty up to and including jetty 6.1.16 and 7.0.0.M2
    On a vulnerable server, a crafted URL may access files outside of
    the web application or document tree.

    To be vulnerable to this issue, you must EITHER:

     - be using the DefaultServlet with support for aliases
       explicitly turned on.


     - be using the ResourceHandler class to serve static content.

    Furthermore, on unix systems, system are only vulnerable if a directory
    with a name ending with the character '?' to exist in the webapp or
    docroot. On unix, this is an unlikely situation.

    On windows systems, this directory does not need to exist, so the
    vulnerability requires only a single change from the default

    A 6.1.17 release will be available shortly with this vulnerability
    closed.  Some immediate preventative actions are listed below.

    If you are not using the ResourceHandler, then you should
    confirm that your jetty instance is running with
    the Default servlet "aliases" initParam set to "false".
    You will find this setting in either your application's
    web.xml or the etc/webdefault.xml. If it is not set,
    then it takes the default, safe, value of "false".
    You should also check that the org.mortbay.util.FileResource.checkAliases
    system property is either not set, or set to true.

    If you are using the ResourceHandler, then you can secure your
    system against this vulnerability by compiling the source
    at the bottom of this message against the version of Jetty
    that you are using.  Use an instance of this class instead
    of the ResourceHandler

    package org.mortbay.jetty.cert;
    import org.mortbay.jetty.handler.ResourceHandler;
    import org.mortbay.resource.Resource;
    import org.mortbay.util.StringUtil;
    import org.mortbay.util.URIUtil;
    public class TempFixResourceHandler extends ResourceHandler
        public Resource getResource(String path) throws MalformedURLException
            if (path!=null && path.indexOf('?')>=0)
                if (path==null)
                    return null;
            return super.getResource(path);

    Vendor Information

Vendor References



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