CVE-2017-9575 in Mobile Banking App
Summary
by MITRE
The "FVB Mobile Banking" by First Volunteer Bank of Tennessee app 3.1.1 -- aka fvb-mobile-banking/id551018004 for iOS does not 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 • 10/18/2019
The CVE-2017-9575 vulnerability affects the FVB Mobile Banking application version 3.1.1 for iOS devices, representing a critical security flaw in the mobile banking ecosystem. This vulnerability stems from the application's improper implementation of SSL/TLS certificate verification mechanisms, which are fundamental components of secure communications between mobile banking applications and their backend servers. The flaw specifically impacts the app's ability to validate X.509 certificates presented by SSL servers during the secure communication establishment process.
The technical nature of this vulnerability aligns with CWE-295, which addresses improper certificate validation in secure communication protocols. The mobile banking application fails to properly validate the certificate chain presented by servers, allowing attackers to conduct man-in-the-middle attacks by presenting forged certificates that appear legitimate to the vulnerable application. This weakness occurs at the transport layer security validation step where the application should verify certificate authenticity through proper certificate chain validation, issuer verification, and public key consistency checks. The vulnerability essentially disables the cryptographic security mechanisms designed to protect sensitive financial data transmitted between the mobile device and the bank's servers.
The operational impact of this vulnerability is severe and multifaceted for both end users and the financial institution. Mobile banking users face significant risks including unauthorized access to their financial accounts, theft of login credentials, and potential fraudulent transactions. Attackers can intercept and manipulate sensitive data such as account balances, transaction histories, and personal identification information. The vulnerability creates a persistent threat vector that remains active as long as the vulnerable application version is installed on user devices. Financial institutions face reputational damage, regulatory compliance issues, and potential liability for customer losses resulting from security breaches. This weakness directly violates the security principle of authentication and can be mapped to ATT&CK technique T1071.004 for Application Layer Protocol: DNS, as the compromised application may be used to establish unauthorized communication channels.
Mitigation strategies for this vulnerability should include immediate application updates from First Volunteer Bank of Tennessee to implement proper SSL/TLS certificate validation. The fix should incorporate robust certificate pinning mechanisms, proper certificate chain validation, and implementation of certificate transparency checks. Organizations should also implement network-level monitoring to detect unusual traffic patterns that might indicate man-in-the-middle attacks. Users must be advised to immediately update their mobile banking applications and avoid conducting sensitive transactions on untrusted networks. Security teams should conduct regular vulnerability assessments of mobile applications and implement security testing procedures including SSL certificate validation checks. The remediation process should follow industry standards such as NIST SP 800-52 for certificate management and OWASP Mobile Top 10 for mobile security best practices to ensure comprehensive protection against similar vulnerabilities in the future.