Moodle CVE-2019-14884 Cross Site Scripting Vulnerability

Description

Moodle is prone to a cross-site scripting vulnerability because it fails to properly sanitize user-supplied input. An attacker may leverage this issue to execute arbitrary script code in the browser of an unsuspecting user in the context of the affected site. This may allow the attacker to steal cookie-based authentication credentials and to launch other attacks. Moodle 3.7 through 3.7.2, 3.6 through 3.6.6, 3.5 through 3.5.8 and earlier unsupported versions are vulnerable.

Technologies Affected

• Moodle Moodle 3.5
• Moodle Moodle 3.5.1
• Moodle Moodle 3.5.2
• Moodle Moodle 3.5.3
• Moodle Moodle 3.5.4
• Moodle Moodle 3.5.5
• Moodle Moodle 3.5.6
• Moodle Moodle 3.5.7
• Moodle Moodle 3.5.8
• Moodle Moodle 3.6
• Moodle Moodle 3.6.1
• Moodle Moodle 3.6.2
• Moodle Moodle 3.6.3
• Moodle Moodle 3.6.4
• Moodle Moodle 3.6.5
• Moodle Moodle 3.6.6
• Moodle Moodle 3.7
• Moodle Moodle 3.7.1
• Moodle Moodle 3.7.2

Recommendations

Block external access at the network boundary, unless external parties require service.
Filter access to the affected computer at the network boundary if global access isn’t needed. Restricting access to only trusted computers and networks might greatly reduce the likelihood of a successful exploit.

Run all software as a nonprivileged user with minimal access rights.
When possible, run client software as regular user accounts with limited access to system resources. This may limit the immediate consequences of client-side vulnerabilities.

Deploy network intrusion detection systems to monitor network traffic for malicious activity.
Deploy NIDS to detect and block attacks and anomalous activity such as requests containing suspicious URI sequences. Since the webserver may log such requests, review logs regularly.

Do not follow links provided by unknown or untrusted sources.
Web users should be cautious about following links to websites that are provided by unfamiliar or suspicious sources. Filtering HTML from emails may help remove a possible vector for transmitting malicious links to users.

Set web browser security to disable the execution of script code or active content.
Since a successful exploit of this issue allows malicious script code to execute in web clients, consider disabling support for script code and active content within a client browser. Note that this mitigation tactic might adversely affect legitimate websites that rely on the execution of browser-based script code.

Updates are available. Please see the references or vendor advisory for more information.