CVE-2011-0174 in Mac OS X
Summary
by MITRE
Heap-based buffer overflow in Apple Type Services (ATS) in Apple Mac OS X before 10.6.7 allows remote attackers to execute arbitrary code via a document that contains a crafted embedded OpenType font.
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Analysis
by VulDB Data Team • 10/21/2021
The vulnerability identified as CVE-2011-0174 represents a critical heap-based buffer overflow within Apple Type Services, a core component of macOS operating systems. This flaw exists in Apple Mac OS X versions prior to 10.6.7 and specifically affects the processing of embedded OpenType fonts within documents. The vulnerability stems from inadequate input validation and memory management practices when handling font data, creating a condition where maliciously crafted font elements can overwrite adjacent memory locations in the heap. The flaw is particularly dangerous because it operates within a system service that processes font rendering for various applications, making it accessible through routine document handling operations. Attackers can exploit this vulnerability by embedding a specially crafted OpenType font within a document, which then triggers the buffer overflow when the system attempts to render or process the font. This vulnerability is classified under CWE-121 as a heap-based buffer overflow, which occurs when a program writes beyond the boundaries of heap-allocated memory, potentially allowing arbitrary code execution.
The operational impact of this vulnerability extends across multiple attack vectors and system components within the macOS ecosystem. When a user opens a document containing the malicious font, the Apple Type Services component automatically processes the embedded font data, triggering the buffer overflow condition in the heap memory space. The exploitation mechanism leverages the fact that many applications on macOS automatically embed fonts within documents, making this attack vector particularly effective and difficult to detect. The vulnerability allows remote attackers to execute arbitrary code with the privileges of the user running the affected application, potentially leading to complete system compromise. This type of vulnerability aligns with ATT&CK technique T1059.007 for Windows and similar techniques for macOS, where adversaries leverage system services to execute malicious code. The vulnerability affects not just the specific applications that handle documents but impacts the entire operating system's font processing pipeline, making it a widespread threat across the macOS platform.
Mitigation strategies for CVE-2011-0174 require immediate system updates and comprehensive security hardening measures. The primary and most effective mitigation is upgrading to Apple Mac OS X 10.6.7 or later versions, which contain patches specifically addressing the heap overflow condition in Apple Type Services. Organizations should implement automated patch management systems to ensure all macOS devices receive updates promptly. Additionally, system administrators should consider implementing application sandboxing and privilege separation techniques to limit the potential damage from successful exploitation attempts. Network-level protections such as content filtering and email scanning can help prevent the delivery of malicious documents containing crafted fonts. Security monitoring should include detection of unusual font processing activities and memory allocation patterns that may indicate exploitation attempts. The vulnerability demonstrates the importance of input validation and memory safety practices in system services, aligning with security best practices outlined in the OWASP Top 10 and NIST cybersecurity frameworks. Organizations should also consider implementing runtime protections and heap memory corruption detection mechanisms to provide additional layers of defense against similar vulnerabilities in the future.