CVE-2009-2465 in Firefox
Summary
by MITRE
Mozilla Firefox before 3.0.12 and Thunderbird allow remote attackers to cause a denial of service (memory corruption and application crash) or execute arbitrary code via vectors involving double frame construction, related to (1) nsHTMLContentSink.cpp, (2) nsXMLContentSink.cpp, and (3) nsPresShell.cpp, and the nsSubDocumentFrame::Reflow function.
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Analysis
by VulDB Data Team • 08/12/2021
This vulnerability affects Mozilla Firefox versions prior to 3.0.12 and Thunderbird email clients, representing a critical memory corruption issue that can lead to both denial of service conditions and remote code execution. The flaw resides in the handling of HTML and XML content parsing within the browser's rendering engine, specifically in three key files: nsHTMLContentSink.cpp, nsXMLContentSink.cpp, and nsPresShell.cpp. These components are responsible for processing and constructing document frames during content rendering, making them prime targets for exploitation through malformed content construction sequences.
The technical implementation of this vulnerability occurs through the nsSubDocumentFrame::Reflow function which manages the reflow process for subdocuments within the browser's frame hierarchy. When processing specially crafted HTML or XML content, the reflow function encounters malformed frame construction sequences that trigger memory corruption during the frame building process. This memory corruption manifests as heap corruption or stack corruption depending on the specific vector used by attackers, ultimately causing the application to crash or allowing attackers to execute arbitrary code with the privileges of the compromised user.
The operational impact of this vulnerability extends beyond simple application crashes, as it provides attackers with a pathway for remote code execution within the context of the browser process. Attackers can craft malicious web pages or email content that, when processed by vulnerable versions of Firefox or Thunderbird, will trigger the memory corruption during frame construction. This creates a significant threat vector for phishing attacks, drive-by downloads, and other malicious web-based exploits that can compromise user systems without requiring any user interaction beyond visiting a malicious website or opening a malicious email attachment.
The vulnerability aligns with CWE-121, heap-based buffer overflow, and CWE-122, stack-based buffer overflow, as the memory corruption occurs during the frame construction process where insufficient bounds checking allows attackers to overwrite memory locations. From an attack framework perspective, this vulnerability maps to multiple ATT&CK techniques including T1203, Exploitation for Client Execution, and T1059, Command and Scripting Interpreter, as it enables attackers to execute arbitrary code on compromised systems. The vulnerability also relates to T1071, Application Layer Protocol, as it exploits the HTTP and HTTPS protocols to deliver malicious content that triggers the memory corruption during content processing.
Mitigation strategies should prioritize immediate patching of affected versions to Firefox 3.0.12 and Thunderbird releases, as these updates contain fixes that properly validate frame construction sequences and implement proper bounds checking during the reflow process. Organizations should also implement network-level protections such as web application firewalls and content filtering systems that can detect and block known malicious patterns in HTML and XML content. Additionally, user education regarding safe browsing practices and email security should be emphasized to reduce the risk of encountering malicious content that exploits this vulnerability. Browser security enhancements including sandboxing and privilege separation should also be enabled to limit the potential impact of successful exploitation attempts.