CVE-2012-4012 in KUNAI
Summary
by MITRE
The WebView class in the Cybozu KUNAI application before 2.0.6 for Android allows remote attackers to execute arbitrary JavaScript code, and obtain sensitive information, via a crafted application that places this code into a local file associated with a file: URL.
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Analysis
by VulDB Data Team • 02/21/2019
The vulnerability identified as CVE-2012-4012 affects the Cybozu KUNAI application version 2.0.5 and earlier on Android platforms, representing a critical security flaw in how the application handles web content through its WebView component. This issue stems from improper sanitization of file URLs that contain local file paths, creating a pathway for malicious actors to inject and execute arbitrary JavaScript code within the application's context. The vulnerability specifically targets the WebView class implementation that processes file: URLs, which are typically used to access local resources within the application's sandboxed environment.
The technical exploitation of this vulnerability occurs when a remote attacker crafts a malicious application that places malicious JavaScript code into a local file, which is then accessed through a file: URL. This allows the attacker to bypass normal security restrictions that would typically prevent arbitrary code execution. The flaw enables attackers to execute JavaScript code with the same privileges as the KUNAI application itself, potentially leading to complete compromise of the device. The vulnerability is categorized under CWE-94, which describes "Improper Control of Generation of Code ('Code Injection')" and aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: JavaScript," demonstrating how attackers can leverage web-based scripting languages to gain unauthorized access.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with the ability to obtain sensitive information stored within the application's local storage or memory. This includes user credentials, personal data, and potentially sensitive business information that may be cached or stored locally by the KUNAI application. The attack vector is particularly concerning because it does not require user interaction or device compromise beyond the initial installation of the malicious application, making it a persistent threat. The vulnerability essentially allows attackers to perform man-in-the-middle attacks against the application's own functionality, creating a sophisticated attack scenario where the malicious code executes within the legitimate application's trust boundary.
Organizations using Cybozu KUNAI applications should implement immediate mitigations including updating to version 2.0.6 or later, which contains the necessary patches to address the WebView security flaw. Security teams should also consider implementing network-level controls to monitor for suspicious file: URL access patterns and establish proper application sandboxing measures. The vulnerability demonstrates the importance of proper input validation and the principle of least privilege in mobile application security, where local file access should be strictly controlled and validated before any content execution occurs. Additionally, developers should ensure that all WebView components properly sanitize URL parameters and implement appropriate security headers to prevent unauthorized code injection attacks.
This vulnerability serves as a reminder of the critical importance of secure coding practices in mobile application development, particularly when handling local file system access and web content rendering. The flaw highlights the need for comprehensive security testing including dynamic analysis of web components and proper implementation of security controls that prevent cross-site scripting and code injection attacks. Organizations should also consider implementing mobile application security solutions that can detect and prevent such vulnerabilities in real-time, as well as establishing security awareness programs for developers working with mobile platforms. The attack scenario underscores the necessity of maintaining up-to-date security patches and implementing proper application hardening measures to protect against sophisticated attacks that exploit seemingly simple implementation flaws in core application components.