CVE-2015-5234 in IcedTea-Web
Summary
by MITRE
IcedTea-Web before 1.5.3 and 1.6.x before 1.6.1 does not properly sanitize applet URLs, which allows remote attackers to inject applets into the .appletTrustSettings configuration file and bypass user approval to execute the applet via a crafted web page, possibly related to line breaks.
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Analysis
by VulDB Data Team • 06/20/2022
The vulnerability identified as CVE-2015-5234 affects IcedTea-Web versions prior to 1.5.3 and 1.6.x versions before 1.6.1, representing a critical security flaw in Java applet execution handling. This issue stems from inadequate input validation and sanitization of applet URLs within the web browser plugin component that processes Java applets. The vulnerability specifically targets the .appletTrustSettings configuration file, which serves as a critical security mechanism for managing trusted applet execution permissions. When users encounter web pages containing maliciously crafted applet URLs, the system fails to properly validate these inputs, creating an opportunity for attackers to inject unauthorized applets into the trust settings configuration.
The technical exploitation of this vulnerability leverages improper URL sanitization techniques that fail to adequately handle special characters including line breaks and other control characters. Attackers can craft malicious web pages that contain specially formatted URLs designed to manipulate the parsing logic of the IcedTea-Web component. The vulnerability's root cause aligns with CWE-20, which describes improper input validation, and CWE-77, which addresses command and query injection flaws. The flaw allows attackers to inject applets into the trust configuration file without user consent, effectively bypassing the intended security model that requires explicit user approval before executing potentially malicious code. This represents a significant bypass of the Java security sandbox mechanisms that are fundamental to preventing unauthorized code execution.
The operational impact of CVE-2015-5234 extends beyond simple privilege escalation, as it fundamentally undermines the trust model that users rely upon when interacting with web content. When successful, the attack allows remote code execution within the context of the user's browser session, potentially leading to complete system compromise. The vulnerability creates a persistent threat where malicious applets can be executed automatically without user interaction, as they are already present in the trust configuration file. This attack vector is particularly dangerous because it operates at the browser plugin level, bypassing many traditional web security controls and operating system protections. The attack chain typically involves a user visiting a malicious website, which then triggers the injection mechanism through crafted URL parameters that exploit the insufficient sanitization.
Mitigation strategies for CVE-2015-5234 primarily focus on immediate software updates to versions 1.5.3 or later 1.6.x releases that contain proper URL sanitization patches. System administrators should implement network-level controls to monitor and block known malicious URL patterns, while also ensuring that Java applet execution is disabled in browser configurations where possible. The implementation of strict input validation measures and regular security assessments of web applications that interact with Java applets becomes essential. Organizations should also consider implementing sandboxing solutions and monitoring for unauthorized modifications to the .appletTrustSettings file. This vulnerability demonstrates the critical importance of proper input sanitization in security-critical components and aligns with ATT&CK technique T1059.007 for execution through web-based attacks. The vulnerability also highlights the need for comprehensive security testing of plugin and browser extension components, particularly those that handle user-provided input in security-sensitive contexts.