CVE-2015-6926 in eShop
Summary
by MITRE
The OpenID Single Sign-On authentication functionality in OXID eShop before 4.5.0 allows remote attackers to impersonate users via the email address in a crafted authentication token.
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Analysis
by VulDB Data Team • 12/25/2019
The vulnerability identified as CVE-2015-6926 resides within the OpenID Single Sign-On authentication mechanism of OXID eShop versions prior to 4.5.0, presenting a critical security risk that enables remote attackers to execute unauthorized user impersonation. This flaw specifically targets the authentication token validation process where the system relies on email addresses contained within the token to verify user identity. The vulnerability stems from insufficient validation of the email address field within the authentication token, allowing malicious actors to craft tokens with forged email addresses that the system accepts as legitimate. The technical implementation fails to properly authenticate the token source or validate the integrity of the email address field, creating an attack vector that directly compromises the authentication integrity of the eShop platform.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to assume the identity of legitimate users within the eShop environment. When a user attempts to authenticate via OpenID, the system processes the authentication token and extracts the email address to verify user credentials. However, due to the flawed validation mechanism, an attacker can manipulate the email address field in the token to match that of a target user, thereby gaining unauthorized access to their account and associated privileges. This impersonation capability allows attackers to perform actions within the eShop system as the compromised user, potentially accessing sensitive customer data, modifying product information, processing fraudulent transactions, or executing other malicious activities within the scope of the user's permissions. The vulnerability particularly affects e-commerce environments where user authentication integrity is paramount for protecting both customer information and business operations.
Security implications of this vulnerability align with CWE-287 which addresses improper authentication, and can be mapped to ATT&CK technique T1078 for valid accounts used for lateral movement. The flaw represents a direct violation of authentication security principles where the system fails to properly validate the authenticity of authentication tokens and their constituent components. Organizations using affected versions of OXID eShop face significant risks including data breaches, financial fraud, and reputational damage when this vulnerability is exploited. The attack requires minimal technical expertise as it leverages existing authentication flows rather than requiring complex exploitation techniques, making it particularly dangerous for widespread abuse.
Mitigation strategies for CVE-2015-6926 involve immediate deployment of the vendor-provided patch or upgrade to OXID eShop version 4.5.0 or later, which addresses the authentication token validation flaw. Organizations should implement additional security controls including monitoring for suspicious authentication patterns, validating token integrity through cryptographic signatures, and implementing multi-factor authentication mechanisms to reduce the impact of potential exploitation. Security teams should also conduct comprehensive vulnerability assessments of their eShop environments to identify any other authentication-related vulnerabilities and establish proper logging and alerting for authentication events. The patch implementation specifically addresses the token email address validation issue by strengthening the authentication verification process and ensuring that only properly authenticated tokens are accepted by the system, thereby restoring the intended security controls for OpenID Single Sign-On functionality.