CVE-2010-1618 in Moodle
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the phpCAS client library before 1.1.0, as used in Moodle 1.8.x before 1.8.12 and 1.9.x before 1.9.8, allows remote attackers to inject arbitrary web script or HTML via a crafted URL, which is not properly handled in an error message.
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Analysis
by VulDB Data Team • 05/23/2025
The CVE-2010-1618 vulnerability represents a critical cross-site scripting flaw within the phpCAS client library that affected numerous educational platforms including Moodle versions prior to 1.8.12 and 1.9.8. This vulnerability stems from improper handling of user-supplied input within error message generation, creating an avenue for malicious actors to execute arbitrary web scripts or HTML code within the context of affected applications. The flaw specifically manifests when the phpCAS library processes crafted URLs that contain malicious payloads, which are then reflected in error messages without adequate sanitization or encoding mechanisms.
The technical implementation of this vulnerability involves the phpCAS client library's insufficient validation of input parameters when constructing error responses. When a user accesses a malformed URL or provides invalid authentication parameters, the library generates an error message that includes the raw, unprocessed input from the URL. This failure to properly escape or encode user-supplied data creates an XSS vector where attackers can inject malicious scripts that execute in the victim's browser context. The vulnerability is particularly dangerous because it leverages the library's error handling mechanism, which is typically invoked during authentication flows and user interactions.
From an operational perspective, this vulnerability poses significant risks to organizations using affected versions of Moodle and other platforms relying on phpCAS for authentication. Attackers can exploit this flaw by crafting malicious URLs that, when accessed by authenticated users, would execute scripts in their browsers. These scripts could perform actions such as stealing session cookies, redirecting users to malicious sites, or modifying the application interface. The impact extends beyond simple data theft as the vulnerability can be used to establish persistent footholds within the application environment, potentially enabling further attacks against the underlying system infrastructure.
The vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws in web applications, and demonstrates how insecure input handling can compromise application security. From an attacker's perspective, this vulnerability maps to ATT&CK technique T1566.001, which involves social engineering through malicious links, and T1059.001, which covers command and scripting interpreter usage. The exploitation requires minimal technical skill and can be automated, making it particularly dangerous for widespread deployment. Organizations should prioritize patching affected systems and implementing proper input validation mechanisms to prevent similar vulnerabilities from occurring in other components of their web applications.
The remediation strategy centers on upgrading to phpCAS client library version 1.1.0 or later, which includes proper input sanitization and output encoding for error messages. Additionally, administrators should implement comprehensive input validation at multiple layers of their applications, including URL parameter validation and proper HTML escaping of all user-supplied content. Network-level protections such as web application firewalls can provide additional defense-in-depth measures, though they cannot replace proper code-level fixes. Regular security assessments and vulnerability scanning should be conducted to identify similar input handling issues across the entire application stack, particularly in authentication and session management components where such flaws commonly occur.