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PR08-16: CSRF (Cross-site Request Forgery) on Moodle edit profile page
Vulnerability found: 25/06/2008
Vendor informed: 28/06/2008
Vulnerability fixed: 16/07/2008
Advisory publicly released: 22/07/2008
HTTP requests can be forged due to lack of tokenization. By tricking the
victim to visit a third-party page while being logged in, certain
actions can be forged on behalf of the target user.
- - The victim's user ID ('id') parameter and course ID ('course'
parameter) are required for a successful attack. However, such values
are public as they can be obtained from many sections of the site such as:
user blogs ('/blog/')
public profiles. i.e.: '/user/view.php?id=2&course=1',
or even predicted. i.e.: the user ID of the admin account would be 2.
- - The fields surname, email address and department are supposed to be
non-editable by students. However, such restriction is only graphical
(fields are "type='hidden'"). A student can save the form on his desktop
and change the values of such fields. Once the form is resubmitted, the
values would remain persistently changed in the application.
- - Moodle reveals its version within HTML source code. i.e.: <a
title="moodle 1.6.5 + (2006050550)" href="http://moodle.org/">
Proof of concept (code available on
The following steps can be followed by the attacker to fully compromise
the target Moodle site (gain administrative access):
1. Locate course ID and user ID of administrator user from public
profile. By default the admin's course ID is 1, and his user ID is 2.
2. Get administrator's email address (also included in public profile)
3. Send social engineering email to administrator in order to trick him
to visit the CSRF PoC URL while being logged in. The PoC URL simply
loads a form that submits automatically and changes the victim's profile
settings to include information chosen by the attacker. i.e.: attacker's
~ Example PoC URL:
(see the contents of 'moodle_CSRF_poc.php.txt' for more information)
4. Now the attacker can compromise the targeted account by requesting a
"password reset link" and supplying the email address used in the CSRF
Due to the cross-user interaction nature of Moodle, there are many other
ways the victim user could be tricked to click on the PoC URL. i.e.: by
posting it in a blog post, chat session, etc.
Server: Apache/2.2.2 (Unix) PHP/5.2.1 mod_ssl/2.2.2 OpenSSL/0.9.7l
Moodle 1.6.5 + (2006050550)
Versions affected as confirmed by the vendor:
1.6, 1.7, 1.7.4, 1.7.3, 1.7.2, 1.7.1, 1.6.6, 1.6.5, 1.6.4, 1.6.3, 1.6.2,
Not vulnerable: 1.6.7, 1.7.5
By forging "interesting" requests, the victim's account can be
compromised. i.e.: "Edit profile" (/user/editadvanced.php?id=2&course=1)
which can change the victim's password to the one chosen by the attacker.
By targetting an administrator account, the attacker can fully
compromise the target Moodle site.
This issue has been tracked as MDL-15450.
Upgrade to 1.6.7, 1.7.5 or any recent nightly or use patch
Credits: Amir Azam and Adrian Pastor 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
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