CVE-2017-5911 in Supermovil App
Summary
by MITRE
The Banco Santander Mexico SA Supermovil app 3.5 through 3.7 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 • 09/24/2020
The vulnerability identified as CVE-2017-5911 affects the Banco Santander Mexico SA Supermovil mobile application version 3.5 through 3.7 on iOS platforms. This represents a critical security flaw in the application's implementation of secure communication protocols that directly impacts the confidentiality and integrity of financial transactions. The issue stems from the application's failure to properly validate SSL/TLS certificates during network communications, creating an exploitable weakness that undermines the fundamental security assurances provided by Transport Layer Security.
The technical flaw manifests as a lack of X.509 certificate verification within the application's secure socket layer implementation. This vulnerability aligns with CWE-295, which specifically addresses improper certificate validation in secure communications. When the application fails to verify server certificates against trusted certificate authorities, it creates a pathway for attackers to perform man-in-the-middle attacks without detection. The absence of proper certificate pinning or validation mechanisms means that malicious actors can present forged certificates that the application will accept as legitimate, effectively bypassing the security infrastructure designed to protect sensitive financial data.
The operational impact of this vulnerability is severe for both the financial institution and its customers. Attackers can exploit this weakness to intercept and manipulate financial transactions, potentially gaining access to user credentials, account information, and transaction details. The vulnerability creates an environment where sensitive data can be exfiltrated without the application's security mechanisms detecting the compromise. This represents a direct violation of the principle of least privilege and confidentiality in financial services, where the integrity of communication channels is paramount to maintaining customer trust and regulatory compliance.
From an attack perspective, this vulnerability maps to multiple ATT&CK techniques including T1046 for network service scanning and T1566 for credential harvesting through social engineering. The man-in-the-middle attack vector allows for persistent surveillance of user activities and potential data exfiltration. Financial institutions face significant regulatory risks as this vulnerability could violate compliance frameworks such as PCI DSS and financial services regulations that mandate secure communication practices. The attack surface is particularly concerning given that mobile banking applications handle highly sensitive information and represent prime targets for sophisticated cybercriminal operations.
Mitigation strategies should include immediate implementation of proper certificate validation mechanisms, including certificate pinning for critical communication endpoints. The application should be updated to enforce strict X.509 certificate validation against trusted certificate authorities and implement proper certificate trust chain verification. Network security controls such as SSL inspection and monitoring should be enhanced to detect anomalous certificate behavior. Organizations should also consider implementing additional layers of authentication and transaction monitoring to detect potential compromise scenarios. Regular security assessments and penetration testing should be conducted to ensure that similar vulnerabilities are not present in other applications or network components that handle sensitive financial data.