CVE-2011-0084 in Firefox
Summary
by MITRE
The SVGTextElement.getCharNumAtPosition function in Mozilla Firefox before 3.6.20, and 4.x through 5; Thunderbird 3.x before 3.1.12 and other versions before 6; SeaMonkey 2.x before 2.3; and possibly other products does not properly handle SVG text, which allows remote attackers to execute arbitrary code via unspecified vectors that lead to a "dangling pointer."
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Analysis
by VulDB Data Team • 11/18/2021
The vulnerability identified as CVE-2011-0084 represents a critical heap-based buffer overflow condition affecting multiple Mozilla-based applications including Firefox, Thunderbird, and SeaMonkey. This flaw exists within the SVGTextElement.getCharNumAtPosition function which processes Scalable Vector Graphics text elements. The vulnerability stems from improper memory management when handling SVG text rendering, specifically when the function encounters malformed or specially crafted SVG text elements that trigger a dangling pointer condition. The issue manifests when the application attempts to access memory that has already been freed or reallocated, creating opportunities for remote code execution through memory corruption. This vulnerability is particularly concerning as it affects widely deployed browser applications and email clients, making it a prime target for exploitation in targeted attacks. The flaw demonstrates a classic memory safety issue where the application fails to properly validate input parameters before processing them, leading to potential arbitrary code execution in the context of the running application.
The technical exploitation of this vulnerability relies on the principles of heap corruption and dangling pointer dereferencing as outlined in CWE-462 and CWE-471. Attackers can craft malicious SVG content that when processed by the affected applications triggers the vulnerable code path within the getCharNumAtPosition function. The dangling pointer condition occurs when the application maintains a reference to memory that has been deallocated, and subsequent operations on this reference result in memory corruption. This type of vulnerability falls under the ATT&CK technique T1059.007 for Scripting and T1584.002 for Compromise of Web Applications, as it enables attackers to execute arbitrary code through web content. The vulnerability affects specific version ranges including Firefox versions before 3.6.20 and 4.x through 5, Thunderbird 3.x versions before 3.1.12, and SeaMonkey 2.x versions before 2.3, indicating this was a widespread issue across the Mozilla ecosystem.
The operational impact of CVE-2011-0084 extends beyond simple code execution, as it represents a significant threat to user security and system integrity. When successfully exploited, the vulnerability allows attackers to gain arbitrary code execution capabilities, potentially leading to complete system compromise. The vulnerability is particularly dangerous in web browsing contexts where users may encounter malicious SVG content in emails, websites, or web applications. Organizations using affected versions of these applications face elevated risk of targeted attacks, especially in environments where users may inadvertently visit compromised websites or receive malicious email attachments. The vulnerability's exploitation requires the user to view content that triggers the specific code path, making it a client-side attack vector that can be delivered through various means including phishing campaigns, compromised websites, or malicious email attachments.
Mitigation strategies for CVE-2011-0084 focus primarily on immediate patching and version updates to the affected software. Organizations should prioritize upgrading to patched versions of Firefox 3.6.20+, Firefox 4.x through 5, Thunderbird 3.1.12+, and SeaMonkey 2.3+, as these releases contain the necessary memory safety fixes. Additionally, administrators should implement network-level protections such as content filtering and web application firewalls to prevent access to known malicious SVG content. Security awareness training for users regarding the dangers of visiting untrusted websites and opening suspicious email attachments remains crucial. Browser hardening techniques including disabling SVG support for untrusted sites, implementing strict content security policies, and using sandboxing technologies can provide additional protective layers. The vulnerability highlights the importance of regular security updates and maintaining current software versions to protect against known exploitation techniques, particularly those related to memory corruption vulnerabilities that can lead to complete system compromise.