CVE-2012-4204 in Firefox
Summary
by MITRE
The str_unescape function in the JavaScript engine in Mozilla Firefox before 17.0, Thunderbird before 17.0, and SeaMonkey before 2.14 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via unspecified vectors.
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Analysis
by VulDB Data Team • 04/19/2021
The vulnerability identified as CVE-2012-4204 represents a critical memory corruption flaw within the JavaScript engine of Mozilla Firefox and related applications. This issue affects versions prior to 17.0 for Firefox and Thunderbird, and before 2.14 for SeaMonkey, making it a widespread concern across multiple browser platforms. The vulnerability stems from improper handling of string escape sequences within the str_unescape function, which forms part of the core JavaScript engine responsible for parsing and executing web content. The flaw allows remote attackers to manipulate memory structures through crafted JavaScript code, potentially leading to arbitrary code execution or system instability.
The technical implementation of this vulnerability involves memory corruption that occurs when the str_unescape function processes malformed or specially crafted escape sequences. This function is designed to handle string unescaping operations in JavaScript, but due to insufficient bounds checking and memory management, attackers can manipulate the function's behavior to overwrite memory locations or trigger heap corruption. The vulnerability operates at the intersection of multiple security domains including buffer overflows, memory corruption, and code execution, making it particularly dangerous in web environments where untrusted code execution is common. This type of flaw is categorized under CWE-121 as a stack-based buffer overflow and aligns with ATT&CK techniques involving code injection and memory corruption.
The operational impact of CVE-2012-4204 extends beyond simple application crashes to potentially enable full system compromise. When exploited successfully, the vulnerability can allow attackers to execute arbitrary code with the privileges of the affected browser process, potentially leading to complete system compromise. The denial of service aspect manifests as application crashes and memory corruption that can be leveraged to disrupt service availability. Given that these affected applications are widely used web browsers, the potential attack surface is extensive, affecting millions of users who may encounter this vulnerability through malicious websites or phishing attacks. The vulnerability's remote exploitation capability means that no user interaction is required beyond visiting a compromised website, making it particularly dangerous in the context of modern web browsing.
Mitigation strategies for this vulnerability primarily focus on immediate version updates to patched releases of Firefox, Thunderbird, and SeaMonkey. Organizations should implement comprehensive patch management procedures to ensure all affected systems receive updates promptly. Additionally, browser hardening measures including sandboxing, privilege separation, and content filtering can provide additional protection layers. Security professionals should monitor for exploitation attempts through network traffic analysis and implement intrusion detection systems to identify potential exploitation attempts. The vulnerability highlights the importance of regular security updates and the need for robust input validation in JavaScript engines. Organizations should also consider implementing web application firewalls and content security policies to limit the impact of potential exploitation attempts. This vulnerability demonstrates the critical importance of maintaining up-to-date security patches and the potential consequences of delayed remediation in widely deployed software applications.