CVE-2010-3768 in Firefox
Summary
by MITRE
Mozilla Firefox before 3.5.16 and 3.6.x before 3.6.13, Thunderbird before 3.0.11 and 3.1.x before 3.1.7, and SeaMonkey before 2.0.11 do not properly validate downloadable fonts before use within an operating system s font implementation, which allows remote attackers to execute arbitrary code via vectors related to @font-face Cascading Style Sheets (CSS) rules.
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Analysis
by VulDB Data Team • 12/08/2024
This vulnerability resides in the font validation mechanisms of several Mozilla applications including Firefox, Thunderbird, and SeaMonkey. The flaw occurs when the software processes downloadable fonts through CSS @font-face rules without adequate validation of font file integrity and structure. Attackers can craft malicious font files that exploit weaknesses in the font parsing code, leading to arbitrary code execution on vulnerable systems. The vulnerability affects versions prior to the specified patches, making it a significant concern for organizations running older software versions. The issue stems from insufficient input validation and sanitization of font data, particularly when these fonts are integrated into the operating system's font rendering system.
The technical exploitation involves leveraging the CSS @font-face functionality to load malicious font files that contain crafted payloads. When the browser or email client processes these fonts for display, the vulnerable font parser executes the embedded malicious code within the context of the application's privileges. This represents a classic code execution vulnerability that can be triggered remotely through web content or email attachments. The vulnerability has been classified under CWE-119 as it involves improper restriction of operations within the bounds of a memory buffer, specifically in the font handling subsystem. The attack surface is particularly broad since font files can be embedded in web pages or delivered through email clients, making the exploitation vector highly accessible.
The operational impact of this vulnerability extends beyond simple code execution to potentially compromise entire user environments. Successful exploitation allows attackers to gain arbitrary code execution with the privileges of the affected application, which typically runs with user-level permissions. This could lead to privilege escalation scenarios or serve as a foothold for further attacks within the network. The vulnerability affects desktop applications rather than web browsers alone, making it particularly dangerous in enterprise environments where email clients are frequently used. Organizations running affected versions are at risk of targeted attacks, as the exploitation requires minimal user interaction beyond viewing malicious content. The vulnerability demonstrates the importance of font handling security in modern applications and the potential for seemingly benign features to become attack vectors.
Mitigation strategies should focus on immediate patching of all affected software versions to ensure proper font validation mechanisms are in place. Organizations should implement network-level controls to block suspicious font file types and monitor for unusual font loading activities. Security teams should consider implementing application whitelisting policies to prevent execution of untrusted font files. Regular security assessments should include font handling code reviews and input validation testing. The vulnerability highlights the need for comprehensive security testing of all code paths involving external data processing, particularly in multimedia and font handling components. Additionally, users should be educated about the risks of opening attachments from untrusted sources and the importance of keeping software updated to protect against known vulnerabilities.