CVE-2016-7667 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 10.2 is affected. macOS before 10.12.2 is affected. The issue involves the "CoreText" component. It allows remote attackers to cause a denial of service via a crafted string.
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Analysis
by VulDB Data Team • 08/16/2020
The vulnerability identified as CVE-2016-7667 resides within Apple's CoreText framework, a critical component responsible for text rendering and typography handling across iOS and macOS operating systems. This flaw affects versions prior to iOS 10.2 and macOS 10.12.2, representing a significant security concern given CoreText's widespread use in text processing throughout the Apple ecosystem. The vulnerability manifests as a remote code execution risk that can be exploited through specially crafted string inputs, potentially leading to system instability and denial of service conditions.
The technical nature of this vulnerability stems from insufficient input validation within the CoreText component's string parsing mechanisms. When processing malformed or specially constructed strings, the framework fails to properly handle memory allocation and string manipulation operations, creating potential buffer overflow conditions or memory corruption scenarios. This weakness operates at the intersection of software security and text processing, where seemingly benign input can trigger catastrophic system behavior. The flaw specifically targets the text rendering pipeline, making it particularly dangerous as text processing occurs frequently across all system components and applications.
The operational impact of CVE-2016-7667 extends beyond simple denial of service, as it represents a potential vector for more sophisticated attacks within the Apple security model. Remote attackers could leverage this vulnerability to disrupt system services, cause application crashes, or potentially escalate privileges depending on the execution context. The vulnerability's classification aligns with CWE-121, which addresses stack-based buffer overflow conditions, and CWE-125, which covers out-of-bounds read scenarios. These weaknesses create opportunities for attackers to manipulate system behavior through carefully crafted text inputs that bypass normal validation checks.
From an adversarial perspective, this vulnerability demonstrates how text processing components can serve as attack surfaces within operating systems, particularly when dealing with international character sets and complex typography rendering. The attack vector typically involves sending maliciously formatted strings through network services, email clients, or other applications that utilize CoreText for text display. This aligns with ATT&CK technique T1059.007, which describes the use of scripting languages and command-line interfaces for exploitation purposes. Organizations using affected Apple products face potential risks including service disruption, data integrity concerns, and possible escalation to more serious security incidents.
Mitigation strategies for CVE-2016-7667 primarily focus on immediate system updates and patch management procedures. Apple released iOS 10.2 and macOS 10.12.2 updates that address the vulnerability through enhanced input validation and improved memory management within the CoreText framework. Organizations should implement comprehensive patch management protocols to ensure all affected devices receive these security updates promptly. Additional defensive measures include network monitoring for suspicious text-based traffic patterns and application whitelisting to limit potential exploitation vectors. Security teams should also consider implementing intrusion detection systems that can identify anomalous text processing behaviors indicative of exploitation attempts. The vulnerability serves as a reminder of the critical importance of text processing security in modern operating systems and the necessity of continuous security assessment of core framework components.