CVE-2011-0175 in Mac OS X
Summary
by MITRE
Multiple buffer overflows in Apple Type Services (ATS) in Apple Mac OS X before 10.6.7 allow remote attackers to execute arbitrary code via a document that contains a crafted embedded TrueType font.
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Analysis
by VulDB Data Team • 10/21/2021
Apple Type Services represents a critical component within macOS that handles font rendering and processing for the operating system's graphical user interface. The vulnerability described in CVE-2011-0175 stems from multiple buffer overflow conditions within ATS that occur when processing specially crafted TrueType font files. These buffer overflows manifest when the system attempts to parse and render embedded fonts within documents, creating opportunities for malicious actors to exploit memory corruption vulnerabilities. The flaw exists in the font parsing routines that fail to properly validate font data lengths and boundaries, allowing attackers to craft malicious font files that exceed allocated buffer sizes during processing.
The technical exploitation of this vulnerability requires attackers to prepare documents containing specifically crafted TrueType fonts that trigger the buffer overflow conditions within ATS. When macOS processes these documents, the system's font rendering engine encounters the malformed font data and attempts to store it in insufficiently sized memory buffers. This memory corruption can be leveraged to overwrite adjacent memory locations, potentially allowing attackers to execute arbitrary code with the privileges of the affected application or system process. The vulnerability's remote nature means that attackers can deliver malicious documents through email attachments, web downloads, or other network-based delivery mechanisms without requiring local access to the target system.
The operational impact of CVE-2011-0175 extends beyond simple code execution, as it affects core system services that handle document processing and font rendering across multiple applications. Any application that utilizes ATS for font handling, including web browsers, word processors, and design tools, becomes vulnerable to this attack vector. The vulnerability's presence in Apple Mac OS X versions prior to 10.6.7 creates a widespread risk across affected systems, as ATS is integral to the system's graphical rendering capabilities. This makes the exploitation particularly dangerous because it can be triggered through common user activities like opening email attachments or visiting compromised websites, making it a prime target for zero-day exploits in the wild.
This vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflows that occur when insufficient memory is allocated for data. The attack pattern follows techniques documented in the MITRE ATT&CK framework under T1059 for execution through legitimate system tools and T1203 for exploitation of vulnerabilities in software components. The exploitability characteristics match those described in the Common Exploitation Techniques section of security literature, where buffer overflows in system services represent high-value targets for attackers seeking persistent access. Apple's response to this vulnerability required immediate patching of the ATS component, with the 10.6.7 update addressing the specific buffer overflow conditions that allowed memory corruption during font processing. Organizations should prioritize patch management for this vulnerability and implement network monitoring to detect potential exploitation attempts targeting the ATS font handling services.