CVE-2009-0154 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 before 10.5.7 allows remote attackers to execute arbitrary code via a crafted Compact Font Format (CFF) font.
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Analysis
by VulDB Data Team • 09/04/2019
The vulnerability identified as CVE-2009-0154 represents a critical heap-based buffer overflow within Apple Type Services (ATS) on Mac OS X systems. This flaw exists in the handling of Compact Font Format (CFF) fonts, which are commonly used in professional typography and document rendering. The vulnerability affects Apple Mac OS X versions 10.4.11 and 10.5 prior to 10.5.7, creating a significant security risk for users who may encounter maliciously crafted font files in email attachments, web content, or downloaded documents. The heap-based nature of this buffer overflow indicates that attackers can manipulate memory allocation patterns to overwrite adjacent heap memory regions, potentially leading to arbitrary code execution.
Apple Type Services serves as a core component in macOS for font management and rendering, processing various font formats including CFF which is based on PostScript Type 1 technology. The buffer overflow occurs when ATS processes malformed CFF font files that contain overly long data structures or improperly formatted metadata. When a vulnerable system attempts to parse such malicious font data, the insufficient bounds checking in the font parsing routines allows attackers to write beyond allocated memory boundaries. This vulnerability specifically targets the heap memory management within ATS, where the overflow can corrupt adjacent memory regions including function pointers, return addresses, or other critical program data structures. The flaw is particularly dangerous because it can be triggered through normal font processing operations, making it exploitable via social engineering attacks or automated web-based delivery mechanisms.
The operational impact of this vulnerability extends beyond simple code execution to encompass potential system compromise and data theft. Attackers exploiting this vulnerability can gain arbitrary code execution privileges within the context of the user running the vulnerable ATS service, potentially allowing for privilege escalation attacks. The attack surface is broad since CFF fonts are commonly encountered in professional document formats, web content, and email attachments, making this vulnerability particularly attractive to threat actors. The vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite heap memory, and can be categorized under ATT&CK technique T1059 for command and scripting interpreter usage in code execution contexts. System administrators and security professionals must understand that this vulnerability can be exploited through various attack vectors including malicious email attachments, compromised websites, or untrusted document sources that contain crafted CFF fonts.
Mitigation strategies for CVE-2009-0154 require immediate system updates and proactive security measures to protect against exploitation attempts. The most effective remediation involves applying Apple's official security patches that address the buffer overflow in ATS font processing routines, specifically targeting the identified versions of Mac OS X. Organizations should implement comprehensive font filtering policies that restrict or quarantine potentially malicious font files, particularly those with CFF format characteristics. Network security controls should include web content filtering that blocks or scans font files from untrusted sources, while endpoint protection solutions should monitor for suspicious font processing activities. Security teams should also consider implementing application sandboxing mechanisms that limit the privileges of font processing applications and establish network segmentation to contain potential exploitation attempts. Regular security assessments and vulnerability scanning should include checks for outdated ATS components and ensure that all systems are running patched versions of macOS. The vulnerability demonstrates the importance of maintaining up-to-date system patches and implementing defense-in-depth strategies that protect against exploitation of font processing vulnerabilities in operating system components.