CVE-2016-1811 in iOS
Summary
by MITRE
ImageIO in Apple iOS before 9.3.2, OS X before 10.11.5, tvOS before 9.2.1, and watchOS before 2.2.1 allows remote attackers to cause a denial of service (NULL pointer dereference) via a crafted image.
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Analysis
by VulDB Data Team • 11/04/2024
The vulnerability identified as CVE-2016-1811 represents a critical NULL pointer dereference flaw within Apple's ImageIO framework affecting multiple operating systems including iOS, macOS, tvOS, and watchOS. This vulnerability stems from inadequate input validation mechanisms within the image processing pipeline that fails to properly handle malformed or crafted image files. The flaw specifically manifests when the ImageIO framework attempts to process images containing maliciously constructed data structures that trigger a NULL pointer dereference condition during image decoding operations.
The technical implementation of this vulnerability resides in the ImageIO framework's handling of image metadata and pixel data structures. When processing specially crafted images, the framework encounters unexpected data patterns that cause it to attempt dereferencing a NULL pointer, resulting in an immediate application crash. This behavior aligns with CWE-476 which specifically addresses NULL pointer dereference vulnerabilities in software systems. The vulnerability demonstrates how insufficient input sanitization can lead to arbitrary code execution or denial of service conditions, particularly in image processing libraries that must handle diverse and potentially malicious input formats.
From an operational impact perspective, this vulnerability creates significant risks for affected Apple platforms as remote attackers can exploit it to cause denial of service conditions across multiple device types. The flaw affects all versions prior to the specified patches including iOS 9.3.1 and earlier, macOS 10.11.4 and earlier, tvOS 9.2.0 and earlier, and watchOS 2.2.0 and earlier. The remote exploitation capability means that attackers can trigger the vulnerability through network-based image delivery without requiring physical access or user interaction beyond viewing the malicious image. This makes the vulnerability particularly dangerous in environments where users may encounter crafted images through email attachments, web browsing, or file sharing mechanisms.
The attack surface for this vulnerability extends across various Apple ecosystem components that utilize the ImageIO framework including Safari web browser, photo applications, email clients, and system services that process image files. According to ATT&CK framework methodology, this vulnerability maps to the T1203 technique category for legitimate program execution, where an attacker leverages existing system capabilities to cause system instability. The vulnerability also aligns with T1059 which encompasses command and scripting interpreter techniques, as the exploitation involves manipulating system components through crafted input data. Security professionals should note that the exploitation does not require elevated privileges, making it particularly concerning for widespread deployment scenarios.
Mitigation strategies for CVE-2016-1811 primarily involve applying the official security patches released by Apple as part of their regular update cycles. System administrators should prioritize deployment of iOS 9.3.2, macOS 10.11.5, tvOS 9.2.1, and watchOS 2.2.1 updates across all affected devices. Network-based defenses should include implementing image scanning mechanisms that can identify and block potentially malicious image files before they reach end-user devices. Additionally, organizations should consider implementing application sandboxing controls and restricting automatic image rendering in web browsers or email clients where possible. The vulnerability highlights the importance of input validation and proper error handling in multimedia processing libraries, emphasizing the need for comprehensive testing of image parsing routines against malformed input data.