CVE-2016-4777 in tvOS
Summary
by MITRE
The kernel in Apple iOS before 10, OS X before 10.12, tvOS before 10, and watchOS before 3 allows attackers to execute arbitrary code in a privileged context or cause a denial of service (invalid pointer dereference) via a crafted app.
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Analysis
by VulDB Data Team • 09/21/2022
The vulnerability identified as CVE-2016-4777 represents a critical kernel-level flaw affecting multiple Apple operating systems including iOS versions prior to 10.0, OS X versions before 10.12, tvOS versions before 10.0, and watchOS versions before 3.0. This issue stems from improper handling of memory pointers within the kernel execution environment, creating a pathway for malicious actors to escalate privileges or disrupt system operations. The flaw manifests when a specially crafted application attempts to manipulate kernel memory structures, leading to potentially catastrophic system consequences.
The technical nature of this vulnerability falls under the category of invalid pointer dereference, a common yet dangerous class of memory corruption issues that can be exploited to gain unauthorized access to system resources. According to CWE classification, this represents a variant of CWE-476 which specifically addresses NULL pointer dereference conditions in software implementations. The vulnerability exploits the kernel's failure to properly validate memory access patterns, allowing a malicious application to craft pointer references that point to invalid memory locations. When the kernel attempts to dereference these invalid pointers, the system experiences unexpected behavior ranging from immediate system crashes to full privilege escalation.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it provides attackers with the capability to execute arbitrary code with kernel-level privileges. This privilege escalation capability enables malicious actors to bypass system security controls, access sensitive data, modify system files, and potentially establish persistent backdoors within affected systems. The implications are particularly severe given that these operating systems were widely deployed across mobile and desktop environments, with millions of devices potentially vulnerable to exploitation. Attackers could leverage this vulnerability to compromise user privacy, steal sensitive information, or disrupt critical services without requiring physical access to target devices.
Mitigation strategies for CVE-2016-4777 primarily focus on applying official security updates from Apple, which address the underlying kernel memory handling flaws through proper pointer validation and memory management protocols. System administrators and users should prioritize immediate deployment of patches for iOS 10.0, OS X 10.12, tvOS 10.0, and watchOS 3.0 releases that contain the necessary kernel fixes. Additionally, organizations should implement network monitoring to detect potential exploitation attempts and maintain robust backup procedures to ensure rapid recovery in case of successful attacks. The vulnerability's exploitation aligns with ATT&CK framework techniques related to privilege escalation and defense evasion, making it particularly concerning for enterprise security environments that require comprehensive threat detection and response capabilities.