CVE-2018-4243 in iOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 11.4 is affected. macOS before 10.13.5 is affected. tvOS before 11.4 is affected. watchOS before 4.3.1 is affected. The issue involves the "Kernel" component. A buffer overflow in getvolattrlist allows attackers to execute arbitrary code in a privileged context via a crafted app.
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Analysis
by VulDB Data Team • 07/25/2024
The vulnerability identified as CVE-2018-4243 represents a critical buffer overflow flaw within the kernel component of multiple Apple operating systems including iOS, macOS, tvOS, and watchOS. This security issue affects versions prior to the specified patches, with iOS before 11.4, macOS before 10.13.5, tvOS before 11.4, and watchOS before 4.3.1 all being susceptible to exploitation. The flaw specifically resides in the getvolattrlist function which handles volume attribute listings, making it a target for privilege escalation attacks that could allow malicious applications to execute arbitrary code with elevated privileges.
The technical nature of this vulnerability stems from improper bounds checking within the kernel's volume attribute handling mechanism. When a crafted application attempts to access volume attributes through the getvolattrlist interface, the kernel fails to properly validate input parameters, leading to a buffer overflow condition. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The buffer overflow occurs at kernel level, meaning that successful exploitation could grant attackers complete control over the affected system's kernel space operations.
The operational impact of CVE-2018-4243 extends beyond simple privilege escalation as it creates a pathway for persistent system compromise that could be leveraged by sophisticated attackers. Once an attacker successfully exploits this vulnerability, they gain the ability to execute arbitrary code with kernel-level privileges, which effectively grants them complete control over the affected device. This capability enables attackers to install malicious software, access encrypted data, modify system files, and potentially establish persistence mechanisms that survive system reboots. The vulnerability's exploitation requires only a crafted application, making it particularly dangerous as it can be delivered through normal app distribution channels without requiring physical access to the device.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1068 which covers "Exploitation for Privilege Escalation" and T1059 which covers "Command and Scripting Interpreter." The attack chain typically begins with a malicious application that appears legitimate to users but contains the exploit code designed to trigger the buffer overflow. This vulnerability represents a classic example of a zero-day exploit that could be weaponized by threat actors to compromise Apple devices before the vendor could release a patch. Organizations and individual users must understand that this vulnerability represents a serious risk to device security and that timely patching is essential to mitigate the potential for exploitation.
The mitigation strategy for CVE-2018-4243 centers on immediate patch deployment through Apple's official update channels. Users should upgrade to the affected operating system versions that contain the necessary security patches, which include iOS 11.4, macOS 10.13.5, tvOS 11.4, and watchOS 4.3.1 or later. System administrators should prioritize deployment of these updates across all managed devices and monitor for any signs of exploitation attempts. Additionally, organizations should implement network monitoring to detect potential exploitation attempts and consider temporary application restrictions for untrusted software until full patch coverage is achieved. The vulnerability demonstrates the importance of kernel-level security and highlights the critical need for regular security updates and proper input validation in system components that handle user-supplied data.