CVE-2015-5939 in Mac OS X
Summary
by MITRE
ImageIO in Apple iOS before 9.1, OS X before 10.11.1, and watchOS before 2.0.1 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via crafted metadata in an image, a different vulnerability than CVE-2015-5935, CVE-2015-5936, and CVE-2015-5937.
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Analysis
by VulDB Data Team • 11/20/2024
This vulnerability resides within Apple's ImageIO framework which serves as the core image processing component across iOS, macOS, and watchOS operating systems. The flaw manifests when the system processes crafted metadata within image files, specifically targeting the way ImageIO handles certain image format specifications. Attackers can exploit this weakness by preparing malicious image files containing specially constructed metadata that triggers memory corruption during the image parsing process. The vulnerability affects multiple Apple platforms including iOS versions prior to 9.1, macOS versions before 10.11.1, and watchOS versions before 2.0.1, demonstrating the widespread nature of the flaw across Apple's ecosystem.
The technical implementation of this vulnerability involves improper bounds checking and memory management within the ImageIO framework's metadata parsing routines. When the system encounters malformed metadata structures in image files, the parsing logic fails to properly validate input parameters, leading to buffer overflows or use-after-free conditions. These memory corruption issues can be leveraged by remote attackers to execute arbitrary code with the privileges of the affected application or system processes. The vulnerability operates at the kernel level in some cases, making it particularly dangerous as it can potentially bypass standard security boundaries and escalate privileges. According to CWE classification, this represents a weakness in input validation and memory safety mechanisms, specifically categorized under CWE-125 for out-of-bounds read conditions and CWE-787 for out-of-bounds write conditions.
The operational impact of CVE-2015-5939 extends beyond simple remote code execution to encompass potential denial of service scenarios that can disrupt system functionality. Attackers can craft malicious image files that when opened by vulnerable applications cause system crashes, application hangs, or complete system instability. This vulnerability is particularly concerning in environments where users frequently download or receive images from untrusted sources, such as email attachments, social media platforms, or web browsing activities. The remote exploitation capability means that attackers do not need physical access to target devices, making this vulnerability particularly dangerous for enterprise environments and mobile users. From an ATT&CK framework perspective, this vulnerability maps to techniques involving initial access through malicious files and privilege escalation through code execution, with potential for lateral movement if exploited successfully.
Mitigation strategies for this vulnerability primarily focus on prompt system updates and patches provided by Apple. Users should immediately install the latest security updates for their respective operating systems, as Apple typically releases patches addressing such memory corruption vulnerabilities. Additionally, organizations should implement strict image file validation policies, particularly for files received from external sources or users. Network-based defenses such as content filtering systems can help prevent malicious image files from reaching end users, while application sandboxing and privilege separation can limit the potential damage if exploitation occurs. Security monitoring should include detection of unusual image processing activities or system crashes that might indicate exploitation attempts. The vulnerability highlights the critical importance of maintaining up-to-date software and implementing defense-in-depth strategies to protect against zero-day exploits that target fundamental system components like image processing frameworks.