CVE-2016-7594 in watchOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 10.2 is affected. macOS before 10.12.2 is affected. watchOS before 3.1.3 is affected. The issue involves the "ICU" component. It allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via a crafted web site.
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Analysis
by VulDB Data Team • 09/20/2024
The vulnerability identified as CVE-2016-7594 represents a critical memory corruption flaw within Apple's International Components for Unicode (ICU) library that affected multiple Apple operating systems. This issue resides in the ICU component responsible for handling international text processing and localization features across Apple's ecosystem. The vulnerability manifests when the affected systems process specially crafted web content that triggers memory corruption within the ICU library implementation. The flaw specifically impacts iOS versions prior to 10.2, macOS versions prior to 10.12.2, and watchOS versions prior to 3.1.3, indicating a widespread exposure across Apple's mobile and desktop platforms. The ICU library serves as a foundational component for text processing, character encoding, and internationalization support, making it a prime target for exploitation given its extensive usage throughout Apple's software stack.
The technical exploitation of this vulnerability occurs through remote code execution via maliciously crafted web content that leverages memory corruption flaws within the ICU implementation. Attackers can construct web pages containing specially formatted Unicode sequences or international text that, when processed by the vulnerable ICU library, triggers buffer overflows or memory corruption conditions. These conditions can lead to arbitrary code execution in the context of the affected application or cause application crashes resulting in denial of service. The memory corruption aspect of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-125, which covers out-of-bounds read conditions. The exploitation mechanism follows patterns consistent with remote code execution vulnerabilities in text processing libraries, where malformed input can cause unpredictable memory behavior and potential privilege escalation.
The operational impact of CVE-2016-7594 extends beyond simple denial of service scenarios to encompass full remote code execution capabilities that could allow attackers to compromise user devices. This vulnerability affects the core text processing capabilities of Apple's operating systems, potentially enabling attackers to execute malicious code with the privileges of the affected application. The widespread nature of the vulnerability across iOS, macOS, and watchOS platforms means that attackers could target users across multiple device types through a single malicious website. The impact on user security is particularly concerning given that the exploitation occurs through web browsing activities, which are fundamental to modern computing. This vulnerability can be exploited in the context of web browsers, email clients, and other applications that utilize the ICU library for text processing, making it a significant threat vector for both individual users and enterprise environments.
Mitigation strategies for CVE-2016-7594 primarily focus on applying official security updates from Apple that patch the ICU library implementation. Users should immediately update to iOS 10.2, macOS 10.12.2, or watchOS 3.1.3 to address the vulnerability. Network administrators should consider implementing web filtering solutions to block access to known malicious sites while updates are being deployed. Security monitoring should be enhanced to detect unusual memory access patterns or application crashes that might indicate exploitation attempts. The vulnerability demonstrates the importance of keeping third-party libraries updated, as the ICU component is widely used across different software platforms and can serve as an attack surface when outdated or unpatched. Organizations should also consider implementing network segmentation and endpoint protection solutions that can detect and prevent exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to techniques involving remote code execution through web-based attacks and could be categorized under the T1059.007 sub-technique for scripting languages or T1203 for exploitation for execution, emphasizing the need for comprehensive defensive measures across multiple security domains including network security, endpoint protection, and application security.