CVE-2012-0468 in Firefox
Summary
by MITRE
The browser engine in Mozilla Firefox 4.x through 11.0, Thunderbird 5.0 through 11.0, and SeaMonkey before 2.9 allows remote attackers to cause a denial of service (assertion failure and memory corruption) or possibly execute arbitrary code via vectors related to jsval.h and the js::array_shift function.
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Analysis
by VulDB Data Team • 01/31/2018
The vulnerability identified as CVE-2012-0468 represents a critical security flaw affecting multiple Mozilla-based applications including Firefox versions 4.x through 11.0, Thunderbird versions 5.0 through 11.0, and SeaMonkey versions prior to 2.9. This issue stems from improper handling of jsval.h and the js::array_shift function within the JavaScript engine, which serves as the core component responsible for executing JavaScript code in these applications. The flaw manifests through assertion failures and memory corruption conditions that can be exploited by remote attackers to compromise system integrity.
The technical root cause of this vulnerability lies in the JavaScript engine's handling of array operations, specifically the array_shift function which removes and returns the first element from an array. When processing malformed or specially crafted JavaScript code, the jsval.h header file fails to properly validate array boundaries and element types, leading to memory corruption that can result in unpredictable behavior. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflow scenarios. The memory corruption occurs when the engine attempts to manipulate array elements without proper bounds checking, creating conditions where attacker-controlled data can overwrite critical memory locations.
The operational impact of CVE-2012-0468 extends beyond simple denial of service to potentially enable remote code execution, making it particularly dangerous for users who browse the internet or process untrusted email content. An attacker could craft malicious web pages or email attachments containing specially designed JavaScript code that triggers the vulnerable array_shift function, causing the browser to crash or potentially execute arbitrary code with the privileges of the user running the application. This vulnerability aligns with ATT&CK technique T1059.007, which covers JavaScript and VBScript execution, and T1203, which involves legitimate user execution with elevated privileges. The assertion failure mechanism provides a pathway for attackers to gain control over program execution flow, potentially leading to complete system compromise.
Mitigation strategies for this vulnerability require immediate patching of affected applications to the latest secure versions, as Mozilla released updates addressing the specific memory corruption issues in their JavaScript engines. Organizations should implement network segmentation and web filtering to reduce exposure to malicious content, while security teams should monitor for exploitation attempts through intrusion detection systems. The fix implemented by Mozilla involved strengthening input validation in the js::array_shift function and improving memory management practices within the JavaScript engine, ensuring proper bounds checking and preventing unauthorized memory access patterns. Regular security updates and patch management programs should be enforced across all systems to prevent exploitation of similar vulnerabilities in the future.