CVE-2015-5511 in HybridAuth Social Login Module
Summary
by MITRE
The HybridAuth Social Login module 7.x-2.x before 7.x-2.13 for Drupal allows remote attackers to bypass the user registration by administrator only configuration and create an account via a social login.
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Analysis
by VulDB Data Team • 06/12/2022
The CVE-2015-5511 vulnerability affects the HybridAuth Social Login module version 7.x-2.x before 7.x-2.13 in Drupal CMS environments, representing a critical access control flaw that undermines the security configuration of user registration processes. This vulnerability specifically targets the module's handling of social login authentication flows, where administrators can configure whether user registration should be restricted to administrative approval only. The flaw allows remote attackers to circumvent these security controls through carefully crafted social login requests, effectively bypassing the intended restriction mechanisms that should prevent unauthorized account creation.
The technical implementation of this vulnerability stems from inadequate validation of user registration permissions within the HybridAuth module's authentication flow. When administrators configure the module to require administrative approval for new user accounts, the system should enforce this restriction across all registration pathways including social login methods. However, the flaw exists in the module's code where it fails to properly check the registration policy settings during social login processing, allowing unauthorized account creation through social authentication channels. This represents a classic privilege escalation vulnerability where an attacker can gain unauthorized access to functionality that should be restricted to privileged users.
The operational impact of this vulnerability extends beyond simple unauthorized account creation, as it fundamentally compromises the integrity of the Drupal site's user management system. Attackers can exploit this weakness to create multiple user accounts without administrative oversight, potentially leading to account flooding, spamming activities, or even more sophisticated attacks such as credential stuffing or social engineering campaigns. The vulnerability is particularly dangerous in environments where social login is enabled for public-facing websites, as it allows attackers to bypass the normal user registration approval workflow that would typically be enforced by administrators. This flaw also creates potential for abuse in scenarios where administrators rely on the module's configuration to control user access and maintain site security.
Organizations affected by CVE-2015-5511 should immediately implement the available patch version 7.x-2.13 of the HybridAuth Social Login module, which addresses the access control bypass by properly enforcing the registration policy settings during social login authentication. Security administrators should also review existing user accounts to identify any unauthorized registrations that may have occurred during the vulnerability window, and consider implementing additional monitoring controls to detect suspicious account creation patterns. The vulnerability aligns with CWE-285, which addresses improper authorization in software systems, and can be categorized under ATT&CK technique T1078 for valid accounts, as attackers can leverage the bypass to establish unauthorized access to the system. Organizations should also consider implementing network-level controls and access monitoring to detect potential exploitation attempts and maintain defense in depth strategies against similar vulnerabilities in third-party modules.