CVE-2017-7490 in Moodle
Summary
by MITRE
In Moodle 2.x and 3.x, searching of arbitrary blogs is possible because a capability check is missing.
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Analysis
by VulDB Data Team • 09/26/2020
The vulnerability identified as CVE-2017-7490 affects Moodle versions 2.x and 3.x, representing a critical access control flaw that undermines the platform's security model. This issue stems from a missing capability check during blog search operations, allowing authenticated users to access blog content that they should not be authorized to view. The vulnerability exists within Moodle's blog subsystem where the application fails to properly validate user permissions when processing search queries, creating an information disclosure risk that can be exploited by malicious actors. This flaw directly violates the principle of least privilege and demonstrates inadequate input validation within the platform's access control mechanisms.
The technical implementation of this vulnerability occurs when users perform blog searches within the Moodle environment, specifically when the system processes search parameters without verifying whether the requesting user possesses the necessary capabilities to access the targeted blog content. The missing capability check creates a path where users can potentially enumerate and retrieve blog posts from other users or courses they should not have access to, effectively bypassing the intended authorization controls. This type of vulnerability falls under CWE-284, which addresses improper access control, and represents a classic example of insufficient authorization checks in web applications. The flaw is particularly concerning because it operates at the application level where user sessions are already authenticated, making it easier for attackers to escalate their privileges and gain unauthorized access to sensitive educational content.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can lead to unauthorized access to personal academic data, confidential course materials, and potentially sensitive communications between educators and students. Attackers could exploit this vulnerability to gather intelligence about user activities, course structures, and educational content that should remain private within the learning management system. The implications are particularly severe in educational environments where privacy and data protection are paramount, as this vulnerability could expose personal information, academic performance data, and institutional communications. This weakness also creates opportunities for targeted attacks and social engineering campaigns that could leverage the discovered information to further compromise the system or individual users. The vulnerability's exploitation does not require elevated privileges beyond basic user authentication, making it accessible to a wide range of potential attackers and increasing the overall risk to the institution's digital ecosystem.
Organizations utilizing Moodle should implement immediate mitigations including applying the latest security patches released by Moodle developers, reviewing and strengthening access control policies, and conducting comprehensive security audits of blog-related functionalities. System administrators should also consider implementing additional monitoring and logging mechanisms to detect unauthorized access attempts and establish network-level controls to limit access to sensitive content. The vulnerability highlights the importance of proper capability checks and input validation within web applications, aligning with ATT&CK technique T1078 which addresses valid accounts and privilege escalation. Regular security assessments and adherence to security best practices including principle of least privilege and defense in depth strategies are essential for preventing similar vulnerabilities from compromising the integrity of educational platforms. Organizations should also ensure that their security monitoring tools are configured to detect anomalous search patterns that might indicate exploitation attempts of this type of access control vulnerability.