CVE-2015-7017 in Mac OS X
Summary
by MITRE
CoreText in Apple iOS before 9.1, OS X before 10.11.1, and iTunes before 12.3.1 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-2015-6975 and CVE-2015-6992.
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Analysis
by VulDB Data Team • 06/24/2022
The vulnerability identified as CVE-2015-7017 represents a critical memory corruption flaw within Apple's CoreText framework affecting multiple operating systems including iOS versions prior to 9.1, macOS versions before 10.11.1, and iTunes versions before 12.3.1. This vulnerability falls under the category of remote code execution and denial of service conditions, demonstrating the inherent risks associated with font processing libraries in operating systems. The CoreText framework serves as a fundamental text rendering engine responsible for handling various font formats and text layout operations across Apple's ecosystem, making it a prime target for attackers seeking to exploit memory management weaknesses in text processing components.
The technical exploitation of this vulnerability occurs through the manipulation of crafted font files that trigger memory corruption during the parsing and rendering process. When CoreText attempts to process these maliciously constructed font files, the improper memory handling leads to buffer overflows, heap corruption, or other memory management errors that can be leveraged by remote attackers to execute arbitrary code with the privileges of the affected application. This type of vulnerability is particularly dangerous because font files are commonly encountered in email attachments, web downloads, and file sharing scenarios, providing multiple attack vectors for threat actors. The flaw specifically relates to how the framework handles certain font format structures and metadata, where insufficient input validation and bounds checking allow attackers to craft font files that cause unexpected memory behavior.
The operational impact of CVE-2015-7017 extends beyond simple denial of service conditions to potentially enable complete system compromise when exploited successfully. Attackers can leverage this vulnerability to execute malicious code on targeted systems, potentially leading to full system control, data exfiltration, or persistent backdoor installation. The vulnerability's presence across multiple Apple platforms including mobile devices, desktop operating systems, and desktop applications creates a wide attack surface that organizations must address. From an attacker perspective, this vulnerability aligns with the attack pattern described in the attack tree methodology where the initial compromise occurs through a seemingly benign font file, demonstrating how common system components can become entry points for sophisticated attacks. The vulnerability's classification under CWE-125 indicates improper input validation and memory handling issues that are commonly exploited in modern attack scenarios.
Mitigation strategies for CVE-2015-7017 primarily focus on immediate system updates and patches provided by Apple to address the memory corruption issues within CoreText. Organizations should prioritize patch management to ensure all affected iOS devices, macOS systems, and iTunes installations are updated to versions containing the necessary security fixes. Additional defensive measures include implementing strict file type filtering for font files, deploying network-based intrusion detection systems that can identify suspicious font file patterns, and establishing security awareness training to educate users about the risks of opening untrusted font files. The vulnerability's nature also suggests implementing application sandboxing and privilege separation techniques to limit the potential damage from successful exploitation attempts. Security professionals should monitor for indicators of compromise related to font file processing and consider implementing automated threat hunting procedures to detect potential exploitation attempts. Organizations should also review their incident response procedures to ensure readiness for potential exploitation of this vulnerability, as the attack surface spans across multiple platform environments requiring coordinated response efforts.