Researchers find vulnerabilities in popular open-source Moodle software that can lead to stolen tests, altered grades, or complete site takeover

Researchers have discovered two major vulnerabilities in a popular open-source online course management system that would let an attacker take over teacher and site administrator accounts.

The Moodle system is used by major universities such as California Polytechnic Institute, Cornell University, UCLA, various school systems, and even the Girl Scouts of America.

Moodle, which competes against commercial e-learning portal tools such as Blackboard/WebCT, contains persistent cross-site scripting (XSS) and cross-site request forgery (CSRF) bugs, according to Adrian Pastor, one of the researchers who discovered the flaws during a penetration test. There are over 46,000 Moodle sites around the world.

The vulnerabilities affect Moodle versions below 1.8.0, according to Moodle, which plans to release details tomorrow on fixes to these and other security issues in the software.

Pastor, senior IT security consultant with ProCheckUp Ltd., says all it takes to exploit one of these vulnerabilities is tricking a teacher or administrative user into clicking on a link posted by a malicious student on his or her school or organization’s Moodle site. That’s all too easy given that Moodle combines online classes with a social networking-type environment consisting of blogs, chats, and public profiles, according to the researchers. Moodle can support up to 200,000 students per site.

“We're not aware of the vulnerabilities we discovered being exploited in the wild, and hope they won't ever be,” says ProCheckUp’s Pastor, who along with his colleague Amir Azam on July 22 will publish details of the vulnerabilities they discovered, as well as proof-of-concept of exploits they wrote.

The persistent XSS exploit developed by ProCheckUp injects a piece of malicious JavaScript in the public blogs section of a Moodle site. The malware steals the session IDs of users who visit the blogs section, and then the attacker can pose as any of those compromised users on the Moodle site -- including his or her professor. Persistent XSS is a more powerful XSS attack where malicious code is stored on a Website for a period of time, and all the user has to do is view the page and he or she becomes infected.

The CSRF exploit, meanwhile, sends a phony “edit profile” request when the victim clicks on the malicious link on the Moodle site. The attacker then hijacks the victim’s email address and can log in as the user and change the victim’s password to his own, thus hijacking the victim’s account as well.

Pastor says although he and Azam have not tested the exploits on Moodle admin accounts, it’s likely they will work on those accounts as well as the teacher accounts they penetration-tested. Hacking a teacher’s account is bad enough -- a student could change grades or steal an exam or someone else’s assignment, for example -- but hacking the admin account would give an attacker complete control of the Moodle site, according to the researchers.

Meanwhile, Moodle sites are also vulnerable to a two-pronged attack using both persistent XSS and CSRF. This would entail an attacker loading an HTML and JavaScript payload into the Moodle site’s blog section. So when a user visits a blog, his email address would be updated to the attacker’s email, and the attacker is then able to take over the account.

According to Moodle’s latest statistics, the e-learning portal platform supports over 2 million courses and over 22 million users.

Pastor, meanwhile, says the Moodle team, including Petr Skoda, was quick to respond to the vulnerabilities when ProCheckUp alerted them.

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About the Author(s)

Kelly Jackson Higgins, Editor-in-Chief, Dark Reading

Kelly Jackson Higgins is the Editor-in-Chief of Dark Reading. She is an award-winning veteran technology and business journalist with more than two decades of experience in reporting and editing for various publications, including Network Computing, Secure Enterprise Magazine, Virginia Business magazine, and other major media properties. Jackson Higgins was recently selected as one of the Top 10 Cybersecurity Journalists in the US, and named as one of Folio's 2019 Top Women in Media. She began her career as a sports writer in the Washington, DC metropolitan area, and earned her BA at William & Mary. Follow her on Twitter @kjhiggins.

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