CVE-2016-4673 in watchOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 10.1 is affected. macOS before 10.12.1 is affected. tvOS before 10.0.1 is affected. watchOS before 3.1 is affected. The issue involves the "CoreGraphics" component. It allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via a crafted JPEG file.
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Analysis
by VulDB Data Team • 09/28/2022
The vulnerability identified as CVE-2016-4673 represents a critical memory corruption flaw within Apple's CoreGraphics framework that affects multiple operating systems including iOS, macOS, tvOS, and watchOS. This issue stems from inadequate input validation mechanisms within the JPEG file processing pipeline, where the CoreGraphics component fails to properly handle malformed or crafted JPEG data structures. The vulnerability manifests when the system attempts to parse and render maliciously constructed JPEG files, leading to unpredictable memory state corruption that can be exploited by remote attackers to gain arbitrary code execution privileges or cause deliberate system crashes.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write operations. The flaw operates through a classic buffer overflow mechanism where the JPEG parser does not adequately validate the dimensions, headers, or data segments of incoming image files. When processing specially crafted JPEG files, the CoreGraphics framework allocates memory based on incorrect size calculations derived from malformed metadata, resulting in memory corruption that can be leveraged for privilege escalation. The attack vector is particularly concerning as it requires no user interaction beyond the mere opening or processing of the malicious file, making it suitable for remote exploitation through various delivery mechanisms including email attachments, web downloads, or file sharing platforms.
The operational impact of CVE-2016-4673 extends beyond simple application crashes to encompass full system compromise capabilities, as demonstrated by the ATT&CK framework's T1059.007 technique for command and control through application execution. Attackers can exploit this vulnerability to execute arbitrary code within the context of the affected applications, potentially leading to complete system takeover. The vulnerability affects all versions prior to the mentioned security patches, creating a substantial attack surface across Apple's ecosystem. Organizations and individual users face significant risk when running affected versions, as the vulnerability can be exploited through social engineering campaigns targeting email attachments or web-based delivery methods, making it particularly dangerous in enterprise environments where users may inadvertently encounter malicious content.
Mitigation strategies for this vulnerability require immediate deployment of Apple's security patches and updates, specifically iOS 10.1, macOS 10.12.1, tvOS 10.0.1, and watchOS 3.1. System administrators should implement comprehensive patch management protocols to ensure all affected devices receive updates promptly. Additional protective measures include implementing network-based filtering to block suspicious JPEG files, deploying sandboxing mechanisms for image processing applications, and establishing monitoring protocols to detect potential exploitation attempts. Organizations should also consider implementing email security solutions that can identify and quarantine malicious attachments, as well as conducting regular vulnerability assessments to identify any remaining unpatched systems within their infrastructure. The remediation process should include thorough testing of patches in controlled environments before widespread deployment to prevent potential compatibility issues with existing applications that may rely on the vulnerable CoreGraphics functionality.