CVE-2012-3957 in Firefox
Summary
by MITRE
Heap-based buffer overflow in the nsBlockFrame::MarkLineDirty function in Mozilla Firefox before 15.0, Firefox ESR 10.x before 10.0.7, Thunderbird before 15.0, Thunderbird ESR 10.x before 10.0.7, and SeaMonkey before 2.12 allows remote attackers to execute arbitrary code via unspecified vectors.
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Analysis
by VulDB Data Team • 10/22/2024
The vulnerability identified as CVE-2012-3957 represents a critical heap-based buffer overflow affecting multiple Mozilla products including Firefox, Thunderbird, and SeaMonkey. This flaw resides within the nsBlockFrame::MarkLineDirty function which is part of the browser's rendering engine responsible for managing block-level elements in web page layouts. The vulnerability affects versions prior to Firefox 15.0 and Firefox ESR 10.x before 10.0.7, Thunderbird before 15.0 and Thunderbird ESR 10.x before 10.0.7, and SeaMonkey before 2.12, creating a widespread impact across the Mozilla ecosystem.
The technical nature of this vulnerability stems from improper memory management within the rendering pipeline where the nsBlockFrame::MarkLineDirty function fails to properly validate input boundaries when processing block-level frame elements. This heap-based buffer overflow occurs when maliciously crafted web content attempts to manipulate the layout engine in a manner that causes the function to write beyond allocated memory boundaries. The flaw can be triggered through various vectors involving HTML content that creates complex block-level structures, particularly when dealing with dynamic content modifications and layout recalculations. The vulnerability maps to CWE-121 Heap-based Buffer Overflow, which specifically addresses buffer overflows occurring in heap memory regions, making it particularly dangerous as it can lead to memory corruption and arbitrary code execution.
The operational impact of this vulnerability is severe and potentially exploitable by remote attackers without user interaction. When successfully exploited, the buffer overflow can result in memory corruption that allows attackers to execute arbitrary code with the privileges of the affected application. This represents a critical escalation from a simple rendering issue to a full remote code execution vulnerability. The attack vector typically involves hosting malicious content on a web server that, when loaded in the vulnerable browser, triggers the flawed function during page rendering. The vulnerability can be exploited through various means including malicious web pages, email content, or even compromised websites that serve content designed to trigger the specific memory corruption scenario.
Security practitioners should implement immediate mitigations including mandatory updates to the latest supported versions of affected Mozilla products. The vulnerability demonstrates the importance of keeping browser software current as it represents a known exploit that has been actively targeted by threat actors. Organizations should also consider implementing web application firewalls and content filtering solutions to detect and block potentially malicious content. Additionally, browser hardening measures such as sandboxing, memory protection mechanisms, and strict content security policies can provide additional defense-in-depth layers. The vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1203 for Exploitation for Client Execution, highlighting the need for comprehensive endpoint protection strategies. Regular security assessments and vulnerability scanning should be conducted to ensure all systems are properly patched and that no legacy installations remain vulnerable to this and similar exploits.