CVE-2012-5809 in Groupon Merchants
Summary
by MITRE
The Groupon Redemptions application for Android does not verify that the server hostname matches a domain name in the subject s Common Name (CN) or subjectAltName field of the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via an arbitrary valid certificate.
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Analysis
by VulDB Data Team • 01/31/2018
The vulnerability identified as CVE-2012-5809 represents a critical SSL certificate validation flaw within the Groupon Redemptions Android application. This weakness stems from improper implementation of SSL/TLS certificate verification mechanisms, specifically failing to validate that the server hostname aligns with the domain names present in either the Common Name field or Subject Alternative Name fields of the X.509 certificate. The vulnerability falls under the broader category of insecure cryptographic implementation as defined by CWE-310 and represents a direct violation of proper SSL certificate validation practices that are fundamental to secure communications.
The technical flaw manifests when the Android application establishes SSL connections to remote servers without performing hostname verification against the certificate presented by the server. This omission creates a significant security gap that allows attackers to conduct man-in-the-middle attacks by presenting valid SSL certificates that do not match the expected domain names. The vulnerability specifically targets the certificate validation process where the application should enforce strict hostname matching but instead accepts any valid certificate regardless of whether it corresponds to the intended server domain. This behavior directly contravenes the security principles outlined in the TLS protocol specifications and industry best practices for secure communications.
The operational impact of this vulnerability is substantial as it enables attackers to impersonate legitimate Groupon servers and intercept or manipulate sensitive user data transmitted through the application. Users of the Groupon Redemptions application would be vulnerable to credential theft, transaction fraud, and other malicious activities when connecting to compromised networks or when attackers successfully execute SSL stripping attacks. The vulnerability affects all users who rely on the application for redeeming deals and accessing their account information, potentially exposing personal data, payment information, and redemption codes to unauthorized parties. This flaw creates an environment where attackers can seamlessly intercept communications between users and Groupon's servers without detection.
Mitigation strategies for this vulnerability should focus on implementing proper SSL certificate validation mechanisms within the Android application. Developers must ensure that the application performs strict hostname verification against both the Common Name and Subject Alternative Name fields of X.509 certificates. The implementation should follow established security standards including proper certificate pinning where appropriate and adherence to the TLS protocol specifications. Organizations should also consider implementing additional security controls such as certificate transparency monitoring and regular security audits of their mobile applications. From an ATT&CK framework perspective, this vulnerability maps to techniques involving credential access and initial access through network infiltration, emphasizing the need for robust transport layer security implementations to prevent such attacks from succeeding. The fix requires comprehensive code review and testing to ensure that all SSL connections properly validate server certificates before establishing secure communications.