CVE-2022-35651 in Moodle
Summary
by MITRE • 07/25/2022
A stored XSS and blind SSRF vulnerability was found in Moodle, occurs due to insufficient sanitization of user-supplied data in the SCORM track details. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website to steal potentially sensitive information, change appearance of the web page, can perform phishing and drive-by-download attacks.
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Analysis
by VulDB Data Team • 08/27/2022
The vulnerability CVE-2022-35651 represents a critical security flaw in the Moodle learning management system that combines both stored cross-site scripting and blind server-side request forgery capabilities. This vulnerability specifically affects the SCORM (Sharable Content Object Reference Model) tracking functionality within Moodle, which is commonly used to track learner interactions with educational content. The flaw arises from inadequate input sanitization mechanisms that fail to properly validate and escape user-supplied data before it is stored and subsequently rendered in web pages. When users access SCORM content that contains malicious payloads, the improperly sanitized data gets stored in the system and executed in the context of other users' browsers, creating a persistent security risk that can affect multiple users over time.
The technical implementation of this vulnerability stems from CWE-79, which describes cross-site scripting flaws where untrusted data is incorporated into web pages without proper validation or encoding. In this case, the SCORM track details feature accepts user input that should be treated as potentially malicious, but the system fails to sanitize this data appropriately. The vulnerability allows attackers to craft specially formatted SCORM packages that contain malicious JavaScript code within track details. When legitimate users view these SCORM packages, their browsers execute the embedded scripts in the context of the vulnerable Moodle site, enabling attackers to perform a wide range of malicious activities. The stored nature of this vulnerability means that once the malicious payload is injected into the system, it persists and affects all subsequent users who access the affected content without requiring them to click on additional links.
The operational impact of CVE-2022-35651 extends far beyond simple script execution, as it creates multiple attack vectors that can be exploited for sophisticated cyber operations. The vulnerability enables attackers to steal session cookies, potentially gaining unauthorized access to user accounts and administrative privileges within the Moodle environment. The XSS capability allows for appearance modification of web pages, which can be used to create convincing phishing attacks that trick users into revealing credentials or other sensitive information. Additionally, the vulnerability can facilitate drive-by-download attacks where malicious software is automatically downloaded and executed on victim machines without their knowledge. The blind SSRF component adds another layer of complexity, as attackers can potentially use the vulnerability to make internal requests to other services within the organization's network, potentially bypassing network segmentation controls and expanding the attack surface. This dual nature of the vulnerability makes it particularly dangerous in enterprise environments where Moodle systems often have access to sensitive educational and administrative data.
Organizations utilizing Moodle should implement immediate mitigations to address CVE-2022-35651, including applying the latest security patches from Moodle's official release cycle and implementing network-based protections such as web application firewalls to filter malicious payloads. The vulnerability's classification under ATT&CK technique T1566.001 for phishing and T1059.007 for scripting languages demonstrates the need for comprehensive security measures that address both the technical flaw and potential exploitation patterns. Administrators should also implement strict content validation policies for SCORM packages, particularly limiting the ability of users to upload content that may contain embedded scripts or external references. Regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other components of the Moodle platform, while user education programs should emphasize the risks of executing untrusted SCORM content. The vulnerability highlights the importance of proper input validation and output encoding practices in web applications, particularly in systems that handle user-generated content, and serves as a reminder of the critical need for regular security updates and vulnerability management processes.