CVE-2008-2305 in Mac OS X
Summary
by MITRE
Heap-based buffer overflow in Apple Type Services (ATS) in Apple Mac OS X 10.4.11 and 10.5 through 10.5.4 allows remote attackers to execute arbitrary code via a document containing a crafted font, related to "PostScript font names."
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Analysis
by VulDB Data Team • 08/17/2019
The vulnerability identified as CVE-2008-2305 represents a critical heap-based buffer overflow within Apple Type Services (ATS) component of Mac OS X operating systems. This flaw exists in versions 10.4.11 and 10.5 through 10.5.4, creating a significant security risk that can be exploited remotely through maliciously crafted font files. The vulnerability specifically targets the processing of PostScript font names within the ATS framework, which is responsible for font handling and rendering across the operating system. When a user opens a document containing a specially crafted font with oversized or malformed PostScript font names, the ATS component fails to properly validate input lengths, leading to memory corruption that can be leveraged by attackers to execute arbitrary code with the privileges of the affected process.
The technical exploitation of this vulnerability occurs through a classic heap overflow attack pattern where malicious input exceeds the allocated buffer space for storing PostScript font name information. The ATS subsystem allocates memory for font name processing without adequate bounds checking, allowing attackers to overwrite adjacent memory locations in the heap. This memory corruption can be carefully orchestrated to overwrite function pointers, return addresses, or other critical control data structures, enabling remote code execution. The vulnerability's classification aligns with CWE-121 Heap-based Buffer Overflow, which specifically addresses buffer overflows occurring in heap memory regions. Attackers typically craft malicious font files that contain oversized font name strings, often exceeding the expected buffer size of 256 or 512 bytes, depending on the specific ATS implementation. The attack vector requires the victim to open a document containing the malicious font, which can be delivered through email attachments, web downloads, or other means of document distribution.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise and potential data theft. Since ATS is a core system component integrated into the Mac OS X font rendering pipeline, exploitation can occur even when users open seemingly benign documents such as pdf files, word processing documents, or image files that embed or reference the malicious font. The privilege escalation aspect of the attack means that malicious code executes with the same privileges as the ATS process, which typically runs with user-level privileges but can potentially be leveraged to gain higher system access. This vulnerability directly maps to ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1068 for Exploitation for Privilege Escalation, as attackers can execute arbitrary code and potentially escalate privileges through the compromised ATS process. The widespread use of font embedding in office documents, web content, and multimedia applications makes this vulnerability particularly dangerous, as users may inadvertently trigger the exploit through routine document opening activities.
Mitigation strategies for CVE-2008-2305 primarily involve applying the official security patches released by Apple, which include updates to the ATS framework and related font handling components. System administrators should prioritize deployment of Mac OS X updates, particularly those addressing the specific ATS vulnerabilities in the affected versions. Additional protective measures include implementing strict document filtering policies that prevent automatic font loading from untrusted sources, disabling automatic font embedding in document processing applications, and employing sandboxing techniques that limit the damage potential of compromised ATS processes. Network-level protections such as content filtering systems can help prevent delivery of malicious documents containing the vulnerable font formats. Organizations should also consider implementing monitoring solutions that detect anomalous font processing activities or memory allocation patterns that could indicate exploitation attempts. The vulnerability highlights the importance of proper input validation and bounds checking in system components handling user-supplied data, reinforcing the need for defensive programming practices and regular security assessments of core system services.