CVE-2015-2215 in Services Single Sign-on Server Helper
Summary
by MITRE
Open redirect vulnerability in the Services single sign-on server helper (services_sso_server_helper) module for Drupal allows remote attackers to redirect users to arbitrary web sites and conduct phishing attacks via unspecified parameters.
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Analysis
by VulDB Data Team • 05/01/2022
The CVE-2015-2215 vulnerability represents a critical open redirect flaw within the services_sso_server_helper module of the Drupal content management system. This module facilitates single sign-on functionality for Drupal sites, creating a potential attack vector that enables malicious actors to manipulate user navigation through crafted URLs. The vulnerability specifically affects the authentication and authorization mechanisms within Drupal's services framework, where user sessions are managed and validated across multiple applications. The flaw exists in the parameter handling logic of the SSO server helper, which fails to properly validate and sanitize input parameters before redirecting users to external destinations.
The technical implementation of this vulnerability stems from inadequate input validation within the services_sso_server_helper module. When users attempt to authenticate through the SSO mechanism, the system processes various parameters that should be strictly validated before any redirect operations occur. Attackers can exploit this weakness by crafting malicious URLs that contain specially formatted redirect parameters, bypassing the normal validation procedures. The vulnerability falls under CWE-601, which specifically addresses open redirect vulnerabilities where applications redirect users to untrusted domains without proper validation. This type of flaw allows attackers to create convincing phishing pages that appear to originate from legitimate Drupal sites, leveraging the trust users place in the authenticated session.
The operational impact of this vulnerability extends beyond simple redirection attacks, creating significant risks for organizations relying on Drupal's SSO functionality. Attackers can leverage this weakness to conduct sophisticated phishing campaigns where users are redirected from trusted Drupal domains to malicious sites designed to capture credentials or install malware. The attack surface is particularly concerning because it affects the core authentication infrastructure, potentially compromising user sessions and allowing unauthorized access to sensitive information. Organizations may experience reputational damage when users encounter malicious redirects, and the vulnerability can be exploited across multiple Drupal installations that utilize the affected services_sso_server_helper module. This weakness aligns with ATT&CK technique T1566, which covers social engineering through phishing, and specifically targets the credential access phase of the attack lifecycle.
Mitigation strategies for CVE-2015-2215 should prioritize immediate patching of the services_sso_server_helper module to ensure proper parameter validation and input sanitization. Organizations should implement strict validation of redirect parameters, ensuring that all URLs are checked against a whitelist of approved domains before any redirect operations occur. Network-level controls such as web application firewalls can provide additional protection by monitoring for suspicious redirect patterns and blocking known malicious URL formats. Security teams should also conduct comprehensive audits of all SSO implementations within their Drupal environments to identify other potential vulnerabilities in authentication flows. Regular security assessments and code reviews should focus on parameter handling mechanisms to prevent similar open redirect flaws from emerging in other components of the system. The vulnerability demonstrates the critical importance of validating all user-supplied input in authentication systems, as highlighted by industry best practices in secure coding standards and OWASP top ten security risks.