CVE-2017-9599 in Mobile Banking App
Summary
by MITRE
The "Fountain Trust Mobile Banking" by FOUNTAIN TRUST COMPANY app 3.0.0 -- aka fountain-trust-mobile-banking/id891343006 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-2017-9599 vulnerability affects the Fountain Trust Mobile Banking iOS application version 3.0.0, representing a critical security flaw in the mobile banking ecosystem. This vulnerability stems from the application's failure to properly validate X.509 certificates during SSL/TLS connections, creating a significant attack surface that compromises the integrity of secure communications between mobile banking clients and backend servers. The flaw specifically manifests in the application's inability to perform proper certificate chain validation, which is fundamental to establishing trust in cryptographic communications.
The technical implementation of this vulnerability resides in the application's SSL/TLS handshake process where certificate verification is either completely omitted or inadequately executed. Mobile banking applications must implement proper certificate pinning or at minimum perform thorough certificate validation against trusted certificate authorities to prevent man-in-the-middle attacks. The absence of this validation mechanism allows attackers to present fraudulent certificates that appear legitimate to the mobile application, enabling them to intercept and potentially modify sensitive financial data transmitted between users and banking servers. This vulnerability directly relates to CWE-295, which addresses improper certificate validation, and aligns with ATT&CK technique T1041 for data manipulation through man-in-the-middle attacks.
The operational impact of this vulnerability extends beyond simple information disclosure to encompass complete financial fraud potential. Attackers can exploit this weakness to intercept login credentials, account details, transaction information, and other sensitive banking data. The vulnerability is particularly dangerous because it affects a mobile banking application where users expect robust security measures to protect their financial assets. The attack vector requires minimal sophistication as attackers can leverage standard man-in-the-middle tools to present crafted certificates that bypass the application's certificate validation mechanisms. This vulnerability essentially undermines the fundamental security model of mobile banking applications by allowing attackers to establish fraudulent secure connections that appear legitimate to users.
Mitigation strategies for this vulnerability should include immediate implementation of proper certificate validation mechanisms within the application, including certificate pinning for critical endpoints, and comprehensive security testing of SSL/TLS implementations. Organizations should implement certificate transparency monitoring and establish robust certificate management processes to prevent unauthorized certificate issuance. The fix requires complete replacement of the SSL/TLS certificate validation logic to ensure proper chain of trust verification against established certificate authorities. Security teams should also conduct thorough penetration testing and vulnerability assessments to identify similar issues in other mobile applications and ensure compliance with industry standards such as PCI DSS and banking regulatory requirements. The vulnerability demonstrates the critical importance of proper cryptographic implementation in financial applications and the severe consequences of inadequate security controls in mobile banking environments.