CVE-2016-4681 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.12.1 is affected. The issue involves the "Core Image" 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.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 08/15/2020
The vulnerability identified as CVE-2016-4681 represents a critical security flaw within Apple's macOS operating system affecting versions prior to 10.12.1. This issue resides within the Core Image framework, which serves as a powerful image processing and rendering engine that handles various multimedia formats including JPEG files. The Core Image component is extensively utilized throughout macOS for image manipulation, graphic rendering, and multimedia processing tasks, making it a prime target for exploitation due to its widespread usage and integration within the system architecture.
The technical nature of this vulnerability stems from improper input validation and memory handling within the JPEG file processing routines of Core Image. When a maliciously crafted JPEG file is processed by the system, the vulnerability manifests through memory corruption issues that can lead to arbitrary code execution or system instability. This flaw operates at the kernel level within the image processing pipeline, where insufficient bounds checking and memory management mechanisms fail to properly handle malformed JPEG data structures. The vulnerability specifically exploits how Core Image parses and interprets JPEG file headers and data segments, leading to buffer overflows or heap corruption that can be leveraged by remote attackers to gain unauthorized system access or cause application crashes.
The operational impact of CVE-2016-4681 extends beyond simple application crashes, presenting significant security risks to macOS users and organizations. Attackers can remotely exploit this vulnerability by delivering malicious JPEG files through various attack vectors including email attachments, web downloads, or compromised websites. Once executed, the vulnerability allows for privilege escalation and potential system compromise, as the memory corruption can be manipulated to redirect execution flow or inject malicious code into system processes. This makes the vulnerability particularly dangerous in enterprise environments where macOS systems may be exposed to untrusted content from external sources, potentially leading to full system compromise or persistent backdoor access.
The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions in software systems, and CWE-787, which covers out-of-bounds write vulnerabilities that can result in memory corruption. From an ATT&CK framework perspective, this vulnerability maps to techniques such as T1059 for command and scripting interpreter execution and T1068 for exploit for privilege escalation. The attack surface is further expanded by the fact that Core Image is integrated into numerous applications and system services, meaning that exploitation can occur through multiple entry points including web browsers, email clients, and image processing applications. Organizations should implement immediate mitigations including updating to macOS 10.12.1 or later, deploying network-based intrusion detection systems to monitor for malicious JPEG file transfers, and conducting comprehensive vulnerability assessments to identify systems running affected versions. Additionally, user education regarding safe file handling practices and application sandboxing measures can help reduce the risk of successful exploitation, though the most effective mitigation remains the timely deployment of Apple's security patches and updates.