CVE-2017-9592 in Mobile Banking App
Summary
by MITRE
The "Your Legacy Federal Credit Union Mobile Banking" by Your Legacy Federal Credit Union app 3.0.1 -- aka your-legacy-federal-credit-union-mobile-banking/id919131389 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 vulnerability identified as CVE-2017-9592 affects the iOS mobile banking application developed by Your Legacy Federal Credit Union, specifically version 3.0.1. This represents a critical security flaw in the application's implementation of secure communication protocols, where the mobile banking client fails to properly validate SSL/TLS certificates presented by remote servers. The absence of proper certificate verification creates a significant attack surface that can be exploited by malicious actors to compromise the confidentiality and integrity of sensitive financial data transmitted between the mobile application and the bank's servers.
This vulnerability stems from the application's failure to implement proper certificate pinning or validation mechanisms that would normally be expected in financial applications handling sensitive user data. The flaw allows attackers to perform man-in-the-middle attacks by presenting fraudulent X.509 certificates that appear legitimate to the vulnerable application. This weakness directly violates fundamental security principles established by industry standards such as the CWE-295 weakness category, which specifically addresses improper certificate validation and certificate pinning failures. The vulnerability operates at the transport layer security level, where the application should be enforcing certificate chain validation according to established cryptographic best practices.
The operational impact of this vulnerability extends beyond simple data interception, as it enables attackers to completely impersonate legitimate banking servers and manipulate transactions in real-time. Mobile banking applications are particularly vulnerable to such attacks due to their reliance on wireless communication channels and the sensitive nature of the data they handle. Attackers could potentially redirect users to malicious servers, capture login credentials, access account balances, initiate unauthorized transfers, or perform other financial transactions without detection. The attack vector is particularly concerning because it requires no special privileges or physical access to the device, making it accessible to remote threat actors with basic network interception capabilities.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1046 which involves network service scanning and T1566 which covers credential harvesting through social engineering or network attacks. The lack of certificate verification creates an environment where attackers can leverage various attack frameworks including those described in the OWASP Mobile Top 10, specifically targeting the M3 weakness category related to insecure communication channels. Organizations should implement certificate pinning mechanisms, regularly update SSL/TLS configurations, and deploy network monitoring solutions to detect and prevent such man-in-the-middle attacks. The remediation involves implementing proper certificate validation procedures that verify certificate chains against trusted Certificate Authorities and potentially implementing additional security layers such as certificate stapling or custom certificate pinning for critical applications handling financial data.
The vulnerability demonstrates a clear failure in the application's security architecture and highlights the importance of following established security frameworks such as NIST SP 800-52 for certificate management and the OWASP Mobile Security Project guidelines. Proper implementation of secure communication protocols in financial applications should include mandatory certificate validation, certificate pinning, and regular security assessments to prevent such critical flaws from being introduced into production environments. Organizations handling sensitive financial data must ensure that their mobile applications implement robust transport layer security measures that protect against active network attacks and maintain the trust relationship between clients and servers.