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PR08-01: Several XSS, a cross-domain redirect and a webroot disclosure on Spyce - Python Server Pages (PSP)

PR08-01: Several XSS, a cross-domain redirect and a webroot disclosure on Spyce - Python Server Pages (PSP)

Vulnerability found: 19th December 2007

Vendor informed: 14th January 2007

Vulnerability fixed: the vendor did not respond, however a workaround has been included in the "Fix" section of this advisory.

Severity: Medium


All Spyce sample scripts that return client-supplied input back to the browser are vulnerable to XSS. It is also possible to redirect users to third-party sites and obtain the webroot path by not submitting required parameters to certain scripts.

Note: tested on Spyce - Python Server Pages version 2.1.3

The following are only some examples that demonstrate XSS:


Other vulnerable scripts and unsanitized parameters:

Script: /demos/chat/
parameter: newline

Script: /docs/examples/formintro.spy
parameter: text1

Script: /docs/examples/formtag.spy
parameter: mytext
parameter: mydate

Script: /docs/examples/redirect.spy
parameter: type

Note: some XSS can only be exploited via POST requests (as opposed to GET). This could be done by using an embedded HTML form with "method='POST'" attribute and a JavaScript snippet that causes the form to auto-submits itself. Such form would be located on a third-party site.

Cross-domain redirect PoC:


Requesting the following URL returns the server's webroot:



An attacker may be able to cause execution of malicious scripting code in the browser of a user who clicks on a link to a Spyce-based site. Such code would run within the security context of the target domain. This type of attack can result in non-persistent defacement of the target site, or the redirection of confidential information (i.e.: session IDs) to unauthorised third parties.

Attackers can redirect victim users to third-party sites. Such behaviour can help attackers perform phishing attacks by redirecting the victim to a spoof login page.


Remove sample scripts from live environments.



Credits: Richard Brain, Jan Fry, and Bruno Kovacs of ProCheckUp Ltd (www.procheckup.com)


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