CVE-2011-0198 in Mac OS X
Summary
by MITRE
Heap-based buffer overflow in Apple Type Services (ATS) in Apple Mac OS X before 10.6.8 allows remote attackers to execute arbitrary code via a crafted embedded TrueType font.
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Analysis
by VulDB Data Team • 11/13/2021
The vulnerability identified as CVE-2011-0198 represents a critical heap-based buffer overflow within Apple Type Services (ATS) component of Mac OS X operating systems. This flaw exists in versions prior to 10.6.8 and specifically affects the processing of embedded TrueType fonts, creating a remote code execution vector that could be exploited by malicious actors. The vulnerability stems from inadequate input validation and memory management within the ATS framework, which is responsible for handling font rendering and type services across the operating system.
The technical implementation of this vulnerability occurs when the ATS component processes malformed or crafted TrueType font files that contain embedded malicious data structures. The heap-based buffer overflow manifests when the system attempts to allocate memory for font data that exceeds the allocated buffer size, leading to memory corruption that can be leveraged to overwrite adjacent memory locations. This type of vulnerability falls under CWE-121, heap-based buffer overflow, which is a well-documented weakness in memory management where data written to heap memory exceeds the allocated buffer boundaries. The attack vector is particularly dangerous because it can be triggered through normal font processing activities, making it accessible to remote attackers who could embed malicious fonts in web pages, documents, or email attachments.
The operational impact of CVE-2011-0198 extends beyond simple code execution capabilities, as it represents a sophisticated attack surface that could enable full system compromise. When successfully exploited, the vulnerability allows attackers to execute arbitrary code with the privileges of the affected application, typically resulting in complete system compromise. The vulnerability's remote nature means that attackers do not need physical access to the target system, making it particularly dangerous in enterprise environments where users may encounter malicious fonts through various digital channels. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as the exploitation could lead to execution of malicious payloads that leverage system shell access.
Mitigation strategies for CVE-2011-0198 primarily focus on immediate system updates and proactive security measures. The most effective remediation involves upgrading to Mac OS X 10.6.8 or later versions where Apple has implemented proper bounds checking and memory management fixes within the ATS component. Organizations should also implement network-based security controls such as web application firewalls and content filtering systems to prevent the delivery of malicious font files. Additionally, security administrators should consider implementing sandboxing measures and privilege separation techniques to limit the potential impact of successful exploitation attempts. The vulnerability demonstrates the importance of proper input validation and memory safety practices in system components that process untrusted data, as highlighted in the CERT/CC vulnerability analysis guidelines and similar security frameworks that emphasize the need for robust buffer overflow protection mechanisms.