CVE-2010-2520 in FreeType
Summary
by MITRE
Heap-based buffer overflow in the Ins_IUP function in truetype/ttinterp.c in FreeType before 2.4.0, when TrueType bytecode support is enabled, allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted font file.
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Analysis
by VulDB Data Team • 09/23/2021
The vulnerability identified as CVE-2010-2520 represents a critical heap-based buffer overflow within the FreeType font rendering library, specifically within the Ins_IUP function located in truetype/ttinterp.c. This flaw affects FreeType versions prior to 2.4.0 and manifests when TrueType bytecode support is enabled, creating a pathway for remote attackers to exploit the system through maliciously crafted font files. The vulnerability operates at the intersection of font processing and memory management, where improper bounds checking in the interpretation of TrueType bytecode instructions leads to memory corruption. The flaw is classified under CWE-121 as a heap-based buffer overflow, which occurs when more data is written to a heap-allocated buffer than its allocated size permits, potentially leading to memory corruption and unpredictable behavior. This vulnerability is particularly concerning because it operates within a widely used font rendering library that is integral to numerous operating systems, applications, and web browsers, making it a prime target for exploitation in various attack scenarios.
The technical exploitation of this vulnerability requires an attacker to craft a specially designed font file that triggers the buffer overflow condition during the execution of the Ins_IUP function. When the vulnerable FreeType library processes this malicious font, the bytecode interpreter fails to properly validate input data lengths against allocated buffer sizes, resulting in memory corruption that can manifest as application crashes or potentially enable arbitrary code execution. The attack vector is remote and requires no special privileges, as the vulnerability can be triggered simply by displaying or processing the malicious font file. This makes the exploit particularly dangerous in web browser environments where users may unknowingly encounter malicious font files through compromised websites or email attachments. The vulnerability's impact extends across multiple platforms and applications that rely on FreeType for font rendering, including but not limited to web browsers, desktop applications, and operating system components.
The operational impact of CVE-2010-2520 is significant, as it can result in both denial of service conditions and potential remote code execution, depending on the specific circumstances of exploitation. The vulnerability's ability to cause application crashes represents a direct threat to system availability and user experience, while the potential for arbitrary code execution introduces serious security implications that could allow attackers to gain unauthorized access to systems. The vulnerability affects the core font processing functionality of systems, meaning that any application that displays text or uses font rendering capabilities becomes a potential target. This makes the exploit particularly dangerous in enterprise environments where font files may be processed through various channels including email systems, web browsers, and document processing applications. The vulnerability's presence in FreeType, which is utilized by major software vendors and operating systems, amplifies its potential impact across a broad range of computing environments.
Mitigation strategies for CVE-2010-2520 primarily focus on updating to FreeType version 2.4.0 or later, which includes patches addressing the buffer overflow condition in the Ins_IUP function. System administrators should prioritize updating their FreeType installations across all affected platforms and applications that rely on this library for font rendering. Additional protective measures include implementing font validation mechanisms that filter or reject suspicious font files before processing, disabling TrueType bytecode interpretation where possible, and employing application sandboxing techniques to limit the potential impact of successful exploitation attempts. Organizations should also consider implementing network-based security controls such as web application firewalls and content filtering systems to prevent the delivery of malicious font files to end-user systems. The vulnerability demonstrates the importance of maintaining up-to-date font rendering libraries and highlights the need for comprehensive security testing of font processing components. From an ATT&CK framework perspective, this vulnerability aligns with techniques involving execution through system services and privilege escalation, as exploitation could potentially enable attackers to execute arbitrary code with the privileges of the affected application. The vulnerability's exploitation also relates to defense evasion techniques, as the attack can occur through legitimate font processing pathways without raising immediate suspicion, making detection more challenging for security monitoring systems.