CVE-2016-4839 in Money Forward
Summary
by MITRE
The Android Apps Money Forward (prior to v7.18.0), Money Forward for The Gunma Bank (prior to v1.2.0), Money Forward for SHIGA BANK (prior to v1.2.0), Money Forward for SHIZUOKA BANK (prior to v1.4.0), Money Forward for SBI Sumishin Net Bank (prior to v1.6.0), Money Forward for Tokai Tokyo Securities (prior to v1.4.0), Money Forward for THE TOHO BANK (prior to v1.3.0), Money Forward for YMFG (prior to v1.5.0) provided by Money Forward, Inc. and Money Forward for AppPass (prior to v7.18.3), Money Forward for au SMARTPASS (prior to v7.18.0), Money Forward for Chou Houdai (prior to v7.18.3) provided by SOURCENEXT CORPORATION do not properly implement the WebView class, which allows an attacker to disclose information stored on the device via a specially crafted application.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 12/23/2020
The vulnerability identified as CVE-2016-4839 affects multiple mobile applications developed by Money Forward Inc. and SOURCENEXT CORPORATION, specifically targeting their implementations of the Android WebView component. This flaw represents a critical security oversight in mobile application development practices where proper sandboxing and security controls are not adequately enforced within the WebView class. The vulnerability manifests in applications that handle financial data and user information, creating a significant risk exposure for users who rely on these services for banking and financial management.
The technical implementation flaw stems from improper configuration and handling of the WebView class within these mobile applications. When applications fail to properly secure their WebView components, they create attack vectors that allow malicious actors to exploit the underlying Android framework. This vulnerability specifically enables attackers to access sensitive information stored locally on the device through crafted malicious applications that leverage the insecure WebView implementation. The flaw falls under CWE-200, which addresses information exposure, and represents a direct violation of proper input validation and secure coding practices in mobile application development.
The operational impact of this vulnerability extends beyond simple information disclosure, as these applications handle highly sensitive financial data including banking credentials, transaction records, and personal identification information. Attackers can potentially access stored cookies, local storage data, and other sensitive information that should remain isolated within the application's secure environment. The vulnerability affects multiple financial applications across different banking institutions, amplifying the potential scope of compromise and creating widespread risk for users of these services. This weakness directly aligns with ATT&CK technique T1056.001, which covers credential access through input injection attacks.
The exploitation of this vulnerability requires attackers to craft specially designed applications that can leverage the insecure WebView implementation to access device-stored information. This represents a sophisticated attack vector that demonstrates the importance of proper mobile application security testing and the implementation of secure coding practices. Organizations developing mobile applications must ensure proper isolation and security controls are implemented within WebView components to prevent unauthorized access to sensitive data. The vulnerability underscores the critical need for comprehensive mobile security testing and adherence to security standards such as those outlined in the OWASP Mobile Security Project, particularly focusing on secure data handling and proper WebView configuration to prevent information disclosure attacks.