CVE-2017-9579 in Mobile Banking App
Summary
by MITRE
The "JMCU Mobile Banking" by Joplin Metro Credit Union app 3.0.0 -- aka jmcu-mobile-banking/id716065893 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-2017-9579 vulnerability affects the JMCU Mobile Banking application version 3.0.0 for iOS, representing a critical security flaw in the mobile banking ecosystem that exposes users to significant financial risks. This vulnerability stems from the application's failure to properly validate X.509 certificates during SSL/TLS connections, creating a fundamental weakness in the cryptographic security infrastructure that protects sensitive financial transactions. The flaw specifically impacts the certificate verification process, which is essential for establishing trust between the mobile client and banking servers. Mobile banking applications rely heavily on proper certificate validation to prevent attackers from impersonating legitimate banking services, and this failure undermines the entire security model designed to protect financial data.
The technical implementation of this vulnerability demonstrates a classic lack of certificate pinning and validation mechanisms within the application's secure communication framework. When the JMCU Mobile Banking app establishes connections to banking servers, it should validate the server's SSL certificate against trusted certificate authorities and verify that the certificate matches the expected hostname. However, the application fails to perform these critical checks, allowing attackers to present fraudulent certificates that appear legitimate to the client. This vulnerability enables man-in-the-middle attacks where malicious actors can intercept and modify communications between the mobile application and banking servers without detection. The flaw essentially removes the cryptographic assurance that data transmitted between the user's device and the financial institution remains private and untampered with during transit.
The operational impact of this vulnerability extends far beyond simple data interception, as it creates opportunities for comprehensive financial fraud and data exfiltration. Attackers can leverage this weakness to steal user credentials, transaction details, account balances, and other sensitive banking information by simply positioning themselves between the user's device and the legitimate banking server. The vulnerability is particularly dangerous because it affects a mobile banking application where users often conduct sensitive financial operations, making it an attractive target for cybercriminals. According to the ATT&CK framework, this represents a technique under T1046 (Network Service Scanning) and T1566 (Phishing) as attackers can exploit this weakness to establish persistent access to banking services. The vulnerability also aligns with CWE-295, which specifically addresses improper certificate validation, and CWE-310, which covers cryptographic issues related to key management and certificate validation.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security improvements in mobile banking applications. Organizations should implement proper certificate pinning mechanisms that validate server certificates against known good certificates rather than relying solely on standard certificate authority validation. The application should enforce strict hostname validation and implement certificate chain validation that checks the entire certificate path from the server certificate to a trusted root certificate. Additionally, security measures should include regular security assessments and penetration testing to identify similar vulnerabilities in mobile applications. The implementation of secure coding practices and adherence to industry standards such as those outlined in NIST SP 800-52 for certificate management would help prevent similar issues in future releases. Mobile banking applications must also consider implementing additional security layers such as mutual authentication and secure key storage to further protect against man-in-the-middle attacks and ensure the integrity of financial transactions conducted through mobile channels.