CVE-2016-4838 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 allows an attacker to execute unintended operations via a specially crafted application.
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Analysis
by VulDB Data Team • 12/23/2020
The vulnerability described in CVE-2016-4838 represents a critical security flaw in multiple mobile banking applications developed by Money Forward Inc. and SOURCENEXT CORPORATION. These applications, which provide financial management services for various Japanese banks including Gunma Bank, SHIGA BANK, SBI Sumishin Net Bank, Tokai Tokyo Securities, THE TOHO BANK, and YMFG, were found to contain a security weakness that could be exploited to perform unauthorized operations. The affected applications were released prior to specific version numbers, indicating that these vulnerabilities were identified and patched in later releases. The flaw specifically relates to how these applications handle specially crafted malicious inputs or commands that could be injected through the application interface or underlying communication protocols.
This vulnerability falls under the category of improper input validation and privilege escalation, commonly classified as CWE-20 - Improper Input Validation and CWE-264 - Permissions, Privileges, and Access Controls. The technical implementation of these mobile applications appears to have failed to properly sanitize or validate user inputs, allowing an attacker to craft malicious payloads that could bypass normal application security controls. The attack vector likely involves manipulating application state or user interface elements to execute unintended operations, potentially including unauthorized financial transactions, data exfiltration, or access to restricted application features. The vulnerability could be exploited through various means including malicious third-party applications, compromised user devices, or through network-based attacks that intercept and modify application communications.
The operational impact of this vulnerability is severe and directly affects the financial security of users who rely on these mobile banking applications for their financial management needs. Attackers could potentially access sensitive financial data, perform unauthorized transactions, or manipulate account information without proper authentication. This represents a significant threat to financial institutions and their customers, as it could lead to direct financial loss, identity theft, and compromise of sensitive banking information. The vulnerability affects multiple applications across different financial institutions, amplifying the potential impact and creating a widespread security risk. Organizations using these applications would face regulatory compliance issues, potential legal liability, and damage to customer trust. The attack could be particularly devastating in a mobile environment where applications often have elevated privileges and direct access to sensitive financial data.
Mitigation strategies for this vulnerability should focus on implementing proper input validation, output encoding, and privilege control mechanisms within the affected applications. Organizations should immediately update all affected applications to their patched versions, with the specific version numbers provided in the vulnerability description. Security measures should include robust sanitization of all user inputs, implementation of proper access controls, and regular security testing of mobile applications. The remediation process should involve thorough code review to identify similar vulnerabilities in other application components, implementation of secure coding practices, and establishment of proper application security testing procedures. Additionally, users should be educated about the importance of keeping their applications updated and should be advised to avoid installing third-party applications from untrusted sources that could potentially exploit similar vulnerabilities. This vulnerability highlights the critical importance of mobile application security in financial services and the necessity of implementing comprehensive security measures throughout the application development lifecycle.