CVE-2011-3232 in Firefox
Summary
by MITRE
YARR, as used in Mozilla Firefox before 7.0, Thunderbird before 7.0, and SeaMonkey before 2.4, allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via crafted JavaScript.
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Analysis
by VulDB Data Team • 11/20/2021
The vulnerability identified as CVE-2011-3232 represents a critical security flaw within the YARR (Yet Another Regular Expression) engine implementation in Mozilla's browser applications. This issue affects Firefox versions prior to 7.0, Thunderbird versions prior to 7.0, and SeaMonkey versions prior to 2.4, indicating a widespread impact across Mozilla's suite of internet applications. The vulnerability stems from improper handling of crafted JavaScript code that leverages regular expression patterns to trigger unexpected behavior in the underlying engine. The flaw specifically manifests when the YARR engine processes malformed or specially constructed regular expressions that can lead to memory corruption or unexpected execution paths within the application's JavaScript engine.
The technical nature of this vulnerability places it firmly within the category of memory corruption issues that can be exploited for both denial of service and arbitrary code execution. The YARR engine, which is responsible for processing regular expressions in JavaScript, fails to properly validate input parameters when handling complex or malformed regular expression patterns. This weakness creates opportunities for attackers to craft JavaScript code that when executed causes the application to behave unpredictably, potentially leading to stack corruption, heap corruption, or other memory management issues. The vulnerability demonstrates characteristics consistent with CWE-125, which describes out-of-bounds read errors, and CWE-787, which covers out-of-bounds write errors, both of which are common in regular expression engine implementations.
The operational impact of CVE-2011-3232 extends beyond simple application crashes, as it presents a potential pathway for remote code execution in vulnerable environments. When exploited, this vulnerability allows remote attackers to cause applications to crash or potentially execute arbitrary code with the privileges of the user running the affected software. The attack surface is particularly concerning given that the vulnerability is triggered through JavaScript execution, which is fundamental to web browsing and email client functionality. Users of affected versions could be compromised simply by visiting malicious websites or opening specially crafted email messages containing the malicious JavaScript code. This makes the vulnerability particularly dangerous in environments where users have limited security awareness or where automated exploitation tools are readily available.
Mitigation strategies for this vulnerability require immediate patching of affected applications to the latest versions that contain fixed implementations of the YARR engine. Organizations should prioritize updating Firefox, Thunderbird, and SeaMonkey installations to versions 7.0 or later, which include the necessary security patches. Additionally, implementing network-level protections such as content filtering systems and web application firewalls can provide additional layers of defense against exploitation attempts. Security teams should also consider implementing runtime protections and monitoring for suspicious JavaScript behavior patterns that might indicate exploitation attempts. The vulnerability highlights the importance of regular security updates and the need for organizations to maintain current patch management processes. From an ATT&CK framework perspective, this vulnerability maps to techniques involving command and control communications and privilege escalation, as exploitation can potentially lead to full system compromise through remote code execution.