CVE-2011-2363 in Firefox
Summary
by MITRE
Use-after-free vulnerability in the nsSVGPointList::AppendElement function in the implementation of SVG element lists in Mozilla Firefox before 3.6.18, Thunderbird before 3.1.11, and SeaMonkey through 2.0.14 allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via vectors involving a user-supplied callback.
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Analysis
by VulDB Data Team • 11/13/2021
The CVE-2011-2363 vulnerability represents a critical use-after-free flaw in the SVG element list implementation within Mozilla Firefox and related products. This vulnerability specifically affects the nsSVGPointList::AppendElement function which handles the manipulation of SVG point lists in the browser's rendering engine. The flaw occurs when the application processes user-supplied callback data that interacts with SVG element lists, creating a scenario where memory previously freed by the application is accessed again. The vulnerability falls under the CWE-416 category of Use After Free conditions, where memory deallocation occurs but subsequent references to that memory remain active. Such memory corruption issues are particularly dangerous in web browsers since they can be exploited to execute arbitrary code or cause system instability.
The technical exploitation of this vulnerability requires an attacker to craft malicious SVG content that triggers the specific code path involving the nsSVGPointList::AppendElement function. When the browser processes this crafted content, the memory management system frees certain objects while the callback mechanism continues to reference them, creating a use-after-free condition. The attack vector typically involves embedding malicious SVG code within web pages or email attachments that are processed by the affected browsers. The vulnerability can be leveraged to cause application crashes through denial of service attacks or potentially escalate to full code execution, depending on the memory layout and exploitation techniques employed. This type of vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, where malicious code execution occurs through browser-based attack surfaces.
The operational impact of this vulnerability extends across multiple Mozilla products including Firefox versions prior to 3.6.18, Thunderbird versions before 3.1.11, and SeaMonkey versions through 2.0.14. Organizations using these affected versions face significant risk as the vulnerability can be exploited through standard web browsing activities, making it particularly dangerous in enterprise environments where users may encounter malicious content. The exploitation of this vulnerability can lead to complete system compromise if successful, as attackers can leverage the use-after-free condition to execute malicious payloads with the privileges of the affected browser process. The vulnerability also impacts the browser's stability and reliability, potentially causing frequent crashes and user experience degradation. Security professionals should note that this vulnerability demonstrates the complexity of memory management in web browser engines and the critical importance of proper object lifecycle management in client-side applications.
Mitigation strategies for CVE-2011-2363 primarily focus on immediate version upgrades to patched releases of the affected Mozilla products. System administrators should prioritize deployment of security updates from Mozilla, which include memory safety improvements and proper handling of SVG element list operations. Additionally, organizations can implement network-based protections such as web application firewalls and content filtering systems that can detect and block malicious SVG content. Browser hardening techniques including sandboxing and privilege separation should be enabled to limit the potential damage from successful exploitation attempts. Regular security assessments and penetration testing should verify that patched systems properly handle SVG content without triggering similar memory corruption issues. The vulnerability underscores the importance of maintaining current security patches and implementing defense-in-depth strategies to protect against browser-based attack vectors that leverage memory corruption flaws.