CVE-2016-6550 in U by BB
Summary
by MITRE
The U by BB&T app 1.5.4 and earlier for iOS does not properly verify X.509 certificates from SSL servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.
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Analysis
by VulDB Data Team • 11/03/2024
The vulnerability identified as CVE-2016-6550 affects the U by BB&T mobile application version 1.5.4 and earlier for iOS devices, representing a critical security flaw in the application's SSL certificate validation mechanism. This issue stems from improper X.509 certificate verification processes that fail to adequately authenticate server identities during secure communication sessions. The flaw creates a significant attack surface that enables malicious actors to execute man-in-the-middle attacks by presenting crafted certificates that appear legitimate to the vulnerable application. Such attacks can compromise the confidentiality and integrity of sensitive user data transmitted through the application's secure channels.
The technical root cause of this vulnerability lies in the application's failure to implement proper certificate chain validation and trust verification procedures. According to CWE-295, this represents a weakness in certificate validation where the application does not properly validate the authenticity of SSL certificates presented by servers. The vulnerability specifically impacts the iOS platform's secure communication stack, where the application's certificate verification logic fails to check certificate revocation status, validate certificate signatures against trusted authorities, or ensure proper certificate expiration dates. This improper validation allows attackers to generate or obtain certificates that can bypass the application's security checks, creating a false sense of security for users.
The operational impact of this vulnerability extends beyond simple data interception, as it fundamentally undermines the trust model that secure mobile banking applications must maintain. Attackers can exploit this weakness to impersonate legitimate banking servers and capture sensitive information including user credentials, account details, transaction data, and personal identification information. The vulnerability affects the core security principle of authentication, as described in the ATT&CK framework under T1552.001 for credentials in files, where compromised certificates can lead to unauthorized access to banking systems. Users conducting financial transactions through the vulnerable application face significant risk of financial loss and identity theft, while the banking institution itself faces potential regulatory penalties and reputational damage.
Mitigation strategies for this vulnerability require immediate remediation through application updates that implement proper SSL certificate validation. Organizations should ensure that all mobile banking applications implement comprehensive certificate pinning mechanisms, utilize trusted certificate authorities, and maintain current certificate revocation checking procedures. The fix should incorporate proper certificate chain validation, signature verification, and expiration date checks as specified in industry standards such as RFC 5280 for X.509 certificate handling. Additionally, implementing certificate transparency measures and regular security audits can help prevent similar vulnerabilities from emerging in future application versions. Network administrators should also consider deploying additional monitoring solutions to detect potential man-in-the-middle attack attempts targeting mobile banking applications.