CVE-2016-4661 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.12.1 is affected. The issue involves the "ntfs" component, which misparses disk images and allows attackers to cause a denial of service via a crafted app.
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Analysis
by VulDB Data Team • 09/28/2022
The vulnerability identified as CVE-2016-4661 represents a critical denial of service flaw within Apple's macOS operating system affecting versions prior to 10.12.1. This security weakness resides within the ntfs component of the system, which is responsible for handling NTFS file system operations and disk image parsing. The flaw manifests when the system encounters crafted applications or disk images that contain malformed data structures, leading to unexpected behavior and system instability.
The technical implementation of this vulnerability stems from inadequate input validation within the ntfs parsing routines that process disk image metadata. When macOS attempts to parse a maliciously crafted application or disk image containing malformed NTFS structures, the parsing logic fails to properly handle edge cases and invalid data sequences. This misparsing behavior triggers a cascade of system errors that ultimately results in the operating system becoming unresponsive or crashing entirely. The vulnerability specifically affects the kernel-level components that manage file system operations, making it particularly dangerous as it can be exploited through seemingly benign applications or disk images.
From an operational perspective, this vulnerability presents significant risks to macOS users and organizations relying on Apple's ecosystem. Attackers can exploit this flaw by distributing malicious applications or disk images that contain specially crafted NTFS metadata designed to trigger the parsing error. Once executed, these malicious payloads can cause immediate system crashes, forcing users to restart their machines and potentially resulting in data loss or service disruption. The impact extends beyond individual user devices as organizations may experience widespread system instability when users inadvertently execute compromised applications, particularly in environments where automated software deployment or shared application distribution occurs.
The vulnerability aligns with CWE-129, which addresses improper validation of input boundaries, and demonstrates characteristics consistent with CWE-125, improper access to memory. From an attacker's perspective, this flaw maps to ATT&CK technique T1499.004, which involves the use of system resource hijacking to cause denial of service conditions. The exploitation requires minimal technical expertise and can be performed through social engineering campaigns or automated distribution of malicious applications through various channels. Organizations should implement immediate mitigation strategies including mandatory system updates to macOS 10.12.1 or later, network-based filtering of suspicious applications, and user education regarding the risks of executing untrusted software. Additionally, system administrators should consider implementing application whitelisting policies to prevent execution of potentially malicious applications that could trigger this vulnerability through the ntfs component parsing mechanisms.