CVE-2015-7008 in Mac OS X
Summary
by MITRE
FontParser in Apple iOS before 9.1 and OS X before 10.11.1 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted font file, a different vulnerability than CVE-2015-6976, CVE-2015-6977, CVE-2015-6978, CVE-2015-6990, CVE-2015-6991, CVE-2015-6993, CVE-2015-7009, CVE-2015-7010, and CVE-2015-7018.
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Analysis
by VulDB Data Team • 11/19/2024
The vulnerability identified as CVE-2015-7008 represents a critical memory corruption flaw within Apple's FontParser component that affects iOS versions prior to 9.1 and OS X versions prior to 10.11.1. This vulnerability resides in the font parsing functionality that processes various font formats including TrueType, OpenType, and other embedded font types that are commonly encountered in digital documents, web content, and system applications. The flaw specifically manifests when the system encounters a crafted malicious font file that has been deliberately constructed to exploit memory handling inconsistencies within the parsing engine. This vulnerability falls under the broader category of code execution through malformed input, which is classified as CWE-121 in the Common Weakness Enumeration framework.
The technical implementation of this vulnerability stems from inadequate bounds checking and memory management during font file parsing operations. When a malicious font file is processed, the FontParser fails to properly validate the structure and size of various font table entries, leading to buffer overflows or memory corruption conditions that can be leveraged by attackers to execute arbitrary code within the context of the affected application. The memory corruption occurs at the level where font data is being read and interpreted, particularly when handling font tables that contain metadata, glyph information, or other structured data elements. Attackers can craft font files that contain oversized data structures or malformed entries that cause the parser to write beyond allocated memory boundaries, potentially corrupting adjacent memory regions or triggering exploitable conditions that allow code execution.
The operational impact of CVE-2015-7009 extends beyond simple denial of service scenarios to encompass full system compromise capabilities. Remote attackers can leverage this vulnerability through various attack vectors including email attachments, web content, malicious websites, or downloadable content that may be processed by applications that utilize Apple's font rendering capabilities. The vulnerability is particularly dangerous because it can be triggered without user interaction in certain contexts, making it a prime candidate for automated exploitation campaigns. When successfully exploited, the vulnerability allows attackers to execute code with the privileges of the affected application, potentially leading to complete system compromise, data exfiltration, or persistent backdoor installation. This aligns with ATT&CK technique T1059 which covers the execution of malicious code through legitimate system processes and applications.
Mitigation strategies for CVE-2015-7008 primarily focus on immediate system updates and patch management to ensure that affected Apple systems receive the necessary security patches. Apple released iOS 9.1 and OS X 10.11.1 updates that addressed this vulnerability through enhanced input validation, improved memory management, and strengthened bounds checking within the FontParser component. Organizations should prioritize immediate deployment of these patches across all affected systems and implement monitoring for potential exploitation attempts. Additional defensive measures include implementing application sandboxing, restricting font processing in email clients and web browsers, and deploying network-based intrusion detection systems that can identify suspicious font file patterns. The vulnerability demonstrates the importance of proper input validation and memory safety practices as outlined in the CERT/CC Secure Coding Standards, particularly emphasizing the need for robust bounds checking and proper memory allocation practices when handling untrusted data inputs.