CVE-2015-5926 in Mac OS X
Summary
by MITRE
The CoreGraphics component 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 a crafted web site, a different vulnerability than CVE-2015-5925.
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Analysis
by VulDB Data Team • 06/24/2022
The vulnerability identified as CVE-2015-5926 represents a critical memory corruption flaw within Apple's CoreGraphics framework that affected multiple operating systems including iOS versions prior to 9.1, OS X versions before 10.11.1, and watchOS versions before 2.0.1. This vulnerability specifically resides in the CoreGraphics component which serves as a fundamental graphics rendering engine responsible for processing and displaying graphical content throughout Apple's ecosystem. The flaw manifests when the system processes maliciously crafted web content that triggers improper memory handling during graphics processing operations, creating an exploitable condition that can be leveraged by remote attackers to gain unauthorized system access.
The technical implementation of this vulnerability involves improper memory management during the parsing of graphics elements within web pages. When a user visits a malicious website containing specially crafted graphics content, the CoreGraphics framework fails to properly validate memory allocations and deallocations, leading to memory corruption that can be exploited to execute arbitrary code with the privileges of the affected application. This memory corruption typically occurs through buffer overflow conditions or use-after-free vulnerabilities within the graphics rendering pipeline, where attacker-controlled data is processed without adequate bounds checking or memory safety mechanisms. The vulnerability is particularly concerning because it operates at the system level within the graphics processing component rather than at the application layer, making it more difficult to detect and mitigate through traditional application sandboxing approaches.
The operational impact of CVE-2015-5926 extends beyond simple denial of service scenarios to encompass full system compromise capabilities that align with ATT&CK technique T1059 for execution and T1190 for exploitation of remote services. Remote attackers can leverage this vulnerability to execute malicious code on targeted systems without requiring physical access or user interaction beyond visiting a compromised website. The memory corruption can result in system crashes, application instability, or more seriously, complete system compromise where attackers gain persistent access to the device. This vulnerability particularly affects web browsing scenarios where users may unknowingly encounter malicious content, making it a significant threat vector for social engineering attacks and drive-by download campaigns. The cross-platform nature of the vulnerability across iOS, OS X, and watchOS systems means that attackers can target multiple device types with a single exploit vector.
Mitigation strategies for CVE-2015-5926 require immediate system updates to the patched versions of the affected operating systems, as Apple released security updates specifically addressing this memory corruption flaw. Organizations should implement network-based protections including web content filtering and intrusion prevention systems to block access to known malicious domains. Additionally, users should be educated about the risks of visiting untrusted websites and the importance of keeping their operating systems updated. The vulnerability demonstrates the importance of memory safety in graphics processing components and aligns with CWE-125 for out-of-bounds read conditions and CWE-787 for out-of-bounds write conditions. Security teams should monitor for exploitation attempts through network traffic analysis and system logs, particularly looking for unusual graphics processing activity or memory allocation patterns that might indicate exploitation attempts. Regular security assessments and vulnerability scanning should include checks for this specific vulnerability across all managed devices to ensure comprehensive protection against this class of memory corruption attacks.