CVE-2010-4010 in Mac OS X
Summary
by MITRE
Integer signedness error in Apple Type Services (ATS) in Apple Mac OS X 10.5.8 allows remote attackers to execute arbitrary code via a crafted embedded Compact Font Format (CFF) font in a document.
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Analysis
by VulDB Data Team • 01/20/2025
The vulnerability identified as CVE-2010-4010 represents a critical integer signedness error within Apple Type Services, a core component of Mac OS X 10.5.8 that manages font rendering and processing. This flaw exists in the handling of Compact Font Format fonts, which are commonly embedded in various document types including pdf files and rich text documents. The vulnerability stems from improper validation of font data structures where signed integer variables are used in contexts that should employ unsigned integers, creating a condition that can be exploited to manipulate memory operations. When a maliciously crafted CFF font is processed by ATS, the signedness error causes incorrect calculations that can lead to buffer overflows or other memory corruption conditions.
The technical exploitation of this vulnerability occurs when a victim opens a document containing a specially crafted CFF font that triggers the integer signedness error during font parsing. This flaw falls under the CWE-190 category of integer overflow or underflow, specifically manifesting as a signed integer overflow where the system attempts to perform arithmetic operations that exceed the maximum value representable by the signed integer type. The vulnerability is particularly dangerous because it leverages the widespread use of font rendering in document processing, making it accessible through common attack vectors such as email attachments, web downloads, or malicious documents. Attackers can construct fonts that, when rendered by ATS, cause memory corruption that can be leveraged to execute arbitrary code with the privileges of the user running the application.
The operational impact of CVE-2010-4010 extends beyond simple code execution to encompass significant security implications for Mac OS X users and organizations. Since the vulnerability affects Apple Type Services, which is integral to the operating system's rendering capabilities, successful exploitation can compromise the entire system without requiring user interaction beyond opening a malicious document. This makes it particularly dangerous in enterprise environments where users may inadvertently open compromised documents from untrusted sources. The vulnerability demonstrates how font processing, often considered a low-risk component, can serve as a sophisticated attack vector that bypasses traditional security measures. The flaw aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as the exploitation may involve code execution through system services, and T1203 for exploitation for privilege escalation through the system's font processing capabilities.
Mitigation strategies for this vulnerability require immediate patching of affected systems, as Apple released security updates to address the integer signedness error in ATS. Organizations should implement comprehensive monitoring for suspicious document handling activities and consider deploying sandboxing solutions that isolate font processing operations. The remediation process should include updating to Mac OS X 10.6 or later versions where the vulnerability has been resolved, as well as implementing strict document filtering policies that prevent automatic font processing of untrusted content. System administrators should also consider disabling unnecessary font rendering capabilities in applications that do not require complex typography support, reducing the attack surface. Additionally, regular security assessments should verify that font handling components are properly configured and that no legacy applications are still processing untrusted font data, as this vulnerability can persist in older system components or third-party applications that rely on ATS for font processing.