CVE-2016-4780 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.12.1 is affected. The issue involves the "Thunderbolt" component. It allows attackers to execute arbitrary code in a privileged context or cause a denial of service (NULL pointer dereference) via a crafted app.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 08/16/2020
The vulnerability identified as CVE-2016-4780 represents a critical security flaw within Apple's Thunderbolt implementation affecting macOS versions prior to 10.12.1. This vulnerability resides in the kernel-level Thunderbolt subsystem that manages hardware connections and data transfers between external devices and the system. The flaw manifests as a NULL pointer dereference condition that occurs when the system processes specially crafted applications designed to exploit the Thunderbolt interface. This type of vulnerability falls under CWE-476 which specifically addresses NULL pointer dereference issues in software implementations.
The technical exploitation of this vulnerability occurs through a malicious application that leverages the Thunderbolt interface to trigger the NULL pointer dereference within the kernel space. When the system attempts to process the crafted application, the Thunderbolt driver fails to properly validate input parameters, resulting in a NULL pointer being dereferenced. This condition can lead to two distinct outcomes depending on the attacker's intent and the system configuration. The first outcome involves privilege escalation allowing attackers to execute arbitrary code within the privileged kernel context, effectively bypassing normal security boundaries. The second outcome results in a denial of service condition that can crash the system or render the Thunderbolt interface unusable.
The operational impact of this vulnerability extends beyond simple system compromise as it affects the fundamental hardware abstraction layer that governs external device connectivity. Attackers exploiting this vulnerability can potentially gain unauthorized access to system resources, escalate privileges, and execute malicious payloads that operate at the kernel level with full system privileges. This represents a significant threat to enterprise environments where Thunderbolt interfaces are commonly used for high-speed data transfer and external device connectivity. The vulnerability is particularly concerning because it operates at the kernel level and can be triggered through legitimate application execution, making detection and prevention challenging.
Security professionals should note that this vulnerability aligns with ATT&CK technique T1059.003 which covers command and scripting interpreter execution, and T1068 which addresses local privilege escalation. The mitigation strategy involves immediate deployment of macOS updates to version 10.12.1 or later, which contains the necessary patches to address the NULL pointer dereference issue. Additionally, system administrators should implement strict application control policies that limit the execution of unsigned or untrusted applications that could potentially exploit this vulnerability through the Thunderbolt interface. Organizations should also consider disabling Thunderbolt interfaces when not actively required for operations, as this reduces the attack surface and minimizes the risk of exploitation. The vulnerability demonstrates the critical importance of kernel-level security controls and proper input validation in preventing privilege escalation attacks that can compromise entire system architectures.