CVE-2012-3423 in IcedTea-Web
Summary
by MITRE
The IcedTea-Web plugin before 1.2.1 does not properly handle NPVariant NPStrings without NUL terminators, which allows remote attackers to cause a denial of service (crash), obtain sensitive information from memory, or execute arbitrary code via a crafted Java applet.
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Analysis
by VulDB Data Team • 12/07/2021
The vulnerability described in CVE-2012-3423 affects the IcedTea-Web browser plugin version 1.2.1 and earlier, representing a critical security flaw in how the plugin processes NPVariant NPStrings. This issue stems from improper handling of string data structures that lack proper null termination, creating a fundamental memory management weakness that can be exploited by malicious actors. The vulnerability exists within the plugin's interpretation of Netscape Plugin Application Programming Interface (NPAPI) data structures, specifically when processing string variants that do not conform to expected null-terminated formats. This flaw demonstrates a classic buffer over-read condition where the plugin attempts to process memory regions beyond the intended string boundaries, potentially exposing sensitive information or causing system instability. The vulnerability's impact extends beyond simple crashes to include potential information disclosure and arbitrary code execution capabilities.
The technical implementation of this vulnerability involves the plugin's failure to validate the integrity of NPString data structures before processing them within the NPAPI framework. When a crafted Java applet presents an NPString without a proper null terminator, the IcedTea-Web plugin performs unsafe memory operations that can result in unpredictable behavior. This issue maps directly to CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write vulnerabilities. The plugin's memory handling routines do not properly validate string lengths or terminators, allowing attackers to manipulate the data flow and potentially execute malicious code. The vulnerability is particularly dangerous because it operates at the plugin level where it can directly interact with the browser's memory space, making it an attractive target for exploitation.
From an operational standpoint, this vulnerability creates significant risks for users running affected versions of the IcedTea-Web plugin. The potential for denial of service attacks means that users could experience unexpected browser crashes or complete system instability when visiting malicious websites. More critically, the information disclosure aspect could expose sensitive memory contents to attackers, potentially including session tokens, personal data, or other confidential information. The arbitrary code execution capability transforms this vulnerability into a full remote exploit that could allow attackers to take complete control of affected systems. This vulnerability impacts the broader Java plugin ecosystem and demonstrates the critical importance of proper input validation in browser plugins that handle untrusted data from web applications.
Mitigation strategies for CVE-2012-3423 primarily focus on immediate remediation through software updates to IcedTea-Web version 1.2.1 or later, which contains the necessary patches to properly handle NPString data structures. Organizations should implement comprehensive patch management procedures to ensure all affected systems receive updates promptly, as this vulnerability has been widely exploited in the wild. Network administrators should consider implementing browser security policies that restrict Java plugin execution or disable it entirely for untrusted websites. The vulnerability also highlights the need for better input validation practices in plugin development and adherence to secure coding guidelines that prevent buffer over-read conditions. Security monitoring should include detection of malicious Java applets that attempt to exploit this specific vulnerability pattern, and incident response procedures should be updated to address potential exploitation attempts. This vulnerability serves as a reminder of the critical security implications of improper memory handling in browser plugins and the importance of maintaining up-to-date security patches across all system components.