CVE-2017-9574 in Mobile Banking App
Summary
by MITRE
The "KC Area Credit Union Mobile Banking" by K C Area Credit Union app 3.0.1 -- aka kc-area-credit-union-mobile-banking/id1097607736 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-2017-9574 affects the KC Area Credit Union Mobile Banking iOS application version 3.0.1, representing a critical security flaw in the mobile banking ecosystem. This issue stems from the application's failure to properly validate X.509 certificates during SSL/TLS communications, creating a significant attack vector that undermines the fundamental security assumptions of secure mobile banking transactions. The vulnerability specifically targets the certificate verification process, which is essential for establishing trust between the mobile client and backend banking servers. According to CWE-295, this represents a weakness in certificate validation mechanisms where the application fails to properly validate the authenticity and integrity of SSL certificates presented by servers. The absence of proper certificate verification creates a dangerous scenario where malicious actors can exploit the trust relationship between the mobile application and banking servers.
The technical implementation flaw manifests when the mobile banking application establishes secure connections to backend services without performing adequate certificate validation checks. This allows attackers to deploy man-in-the-middle attacks by presenting fraudulent certificates that appear legitimate to the vulnerable application. The certificate validation process should typically involve checking certificate chains, verifying issuer authenticity, confirming certificate expiration dates, and ensuring proper hostname matching. However, in this case, the application appears to accept any certificate presented by the server without performing these essential verification steps. This weakness directly violates industry security standards and best practices for mobile application security, particularly in financial contexts where data integrity and confidentiality are paramount. The vulnerability creates an attack surface that enables credential theft, transaction manipulation, and sensitive data exfiltration, making it particularly dangerous for financial applications.
The operational impact of this vulnerability extends far beyond simple data interception, as it fundamentally compromises the security model of mobile banking operations. Attackers can exploit this weakness to impersonate legitimate banking servers and capture sensitive information including user credentials, account details, transaction records, and personal identification data. The consequences for both users and the financial institution are severe, potentially leading to financial losses, identity theft, regulatory violations, and reputational damage. The vulnerability affects the entire user base of the mobile banking application, creating a widespread security risk that cannot be easily mitigated through user awareness alone. Financial institutions face potential regulatory scrutiny under standards such as pci dss and soc 2, which require robust security controls including proper certificate validation for protecting sensitive data. The attack vector is particularly concerning because it operates at the transport layer security level, making it difficult for users to detect malicious activities and potentially allowing prolonged undetected access to banking systems.
Mitigation strategies for CVE-2017-9574 must address both immediate remediation and long-term architectural improvements to prevent similar vulnerabilities. The primary fix involves implementing proper X.509 certificate validation procedures that include certificate chain validation, hostname verification, and certificate expiration checking. Organizations should also implement certificate pinning mechanisms to prevent the acceptance of fraudulent certificates even if they are technically valid. Regular security assessments and penetration testing should be conducted to identify similar validation weaknesses in other mobile applications. Additionally, implementing network monitoring and anomaly detection systems can help identify potential man-in-the-middle attacks. The vulnerability highlights the importance of following established security frameworks such as those recommended by nist and owasp, particularly regarding secure coding practices for mobile applications. Organizations must also consider implementing additional security controls including multi-factor authentication, transaction monitoring, and real-time fraud detection systems to provide defense-in-depth against attacks exploiting this vulnerability. The remediation process should include comprehensive testing to ensure that certificate validation mechanisms function correctly without introducing performance degradation or user experience issues.