CVE-2017-9590 in Mobile Banking App
Summary
by MITRE
The "State Bank of Waterloo Mobile Banking" by State Bank of Waterloo app 3.0.2 -- aka state-bank-of-waterloo-mobile-banking/id555321714 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-2017-9590 vulnerability affects the State Bank of Waterloo Mobile Banking iOS application version 3.0.2, 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 gap in the security infrastructure that financial institutions rely upon to protect customer data. The flaw exists within the certificate verification process, which is fundamental to establishing secure communications between mobile clients and banking servers. According to CWE-295, this represents a weakness in certificate validation where the application fails to properly validate the authenticity and trustworthiness of SSL certificates presented by remote servers.
The technical implementation of this vulnerability allows attackers to execute successful man-in-the-middle attacks by presenting crafted certificates that appear legitimate to the vulnerable application. When the mobile banking app establishes a connection to the bank's server, it does not perform proper certificate chain validation or trust verification against recognized certificate authorities. This means that an attacker positioned between the mobile device and the banking server can intercept communications and present a malicious certificate that the application accepts as valid. The attack vector leverages the absence of proper certificate pinning or validation mechanisms that would normally prevent such certificate substitution attacks.
The operational impact of this vulnerability is severe and directly threatens the confidentiality and integrity of sensitive financial information transmitted through the mobile banking application. Customers using this vulnerable version of the app face significant risk of exposure to financial fraud, identity theft, and unauthorized access to their banking accounts. Attackers can potentially intercept login credentials, account balances, transaction details, and other sensitive personal financial information. The vulnerability undermines the core security model of mobile banking applications, which depend on secure SSL/TLS communications to protect against eavesdropping and data interception. This flaw aligns with ATT&CK technique T1046, where adversaries leverage weak certificate validation to establish persistent access to sensitive systems.
Organizations should implement immediate mitigations including updating to a patched version of the mobile banking application that properly validates X.509 certificates and implements certificate pinning mechanisms. The solution involves ensuring that the application validates certificate chains against trusted root certificates, performs hostname verification, and implements proper certificate trust validation. Security measures should include regular certificate monitoring, implementation of certificate pinning to prevent certificate substitution attacks, and comprehensive testing of SSL/TLS configurations. Additionally, users should be educated about the importance of keeping mobile applications updated and should be advised to avoid using vulnerable versions of financial applications until patches are applied. The vulnerability demonstrates the critical importance of proper cryptographic implementation in mobile financial applications and highlights the need for robust certificate validation processes that align with industry standards such as those specified in NIST SP 800-57 and RFC 5280.