CVE-2012-3971 in Firefox
Summary
by MITRE
Summer Institute of Linguistics (SIL) Graphite 2, as used in Mozilla Firefox before 15.0, Thunderbird before 15.0, and SeaMonkey before 2.12, allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via vectors related to the (1) Silf::readClassMap and (2) Pass::readPass functions.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 01/02/2025
The vulnerability identified as CVE-2012-3971 affects the Summer Institute of Linguistics Graphite 2 library implementation within Mozilla Firefox, Thunderbird, and SeaMonkey applications. This flaw represents a critical memory corruption issue that can be exploited by remote attackers to gain arbitrary code execution or cause system instability through denial of service conditions. The vulnerability specifically targets two distinct functions within the Graphite 2 library: Silf::readClassMap and Pass::readPass, which are responsible for processing linguistic data structures used in text rendering and font handling operations.
The technical root cause of this vulnerability lies in improper input validation and memory management within the Graphite 2 library's parsing functions. When these functions process malformed or specially crafted input data, they fail to properly validate boundaries and memory allocations, leading to buffer overflows or heap corruption conditions. This type of vulnerability falls under the CWE-121 category of "Stack-based Buffer Overflow" and can be classified as a memory corruption vulnerability that allows attackers to manipulate program execution flow. The flaw occurs during the parsing of linguistic font data structures, where insufficient bounds checking enables attackers to overwrite memory regions that control program execution.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to encompass full arbitrary code execution capabilities. Attackers can leverage this vulnerability by crafting malicious font files or web content that triggers the vulnerable Graphite 2 parsing functions when the affected applications process such content. This attack vector is particularly dangerous because it can be delivered through web pages, email attachments, or any content that gets rendered using the affected software's text rendering engine. The vulnerability affects multiple Mozilla products simultaneously, amplifying the potential attack surface and making it a significant concern for organizations using these widely deployed applications. According to ATT&CK framework, this vulnerability maps to T1059.007 (Command and Scripting Interpreter: PowerShell) and T1203 (Exploitation for Client Execution) tactics, as it enables remote code execution through client-side exploitation.
Mitigation strategies for this vulnerability require immediate application updates to versions that contain patches addressing the memory corruption issues in the Graphite 2 library implementation. System administrators should prioritize deployment of security updates for Firefox 15.0, Thunderbird 15.0, and SeaMonkey 2.12, which contain the necessary fixes. Additionally, organizations can implement defensive measures such as disabling Graphite font rendering in affected applications, implementing web content filtering to block suspicious font data, and monitoring for unusual memory allocation patterns or process behavior that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper input validation and memory management practices, particularly in libraries that handle untrusted data from external sources, aligning with security best practices outlined in the OWASP Top Ten and NIST cybersecurity guidelines for secure coding practices.