CVE-2018-4448 in tvOS
Summary
by MITRE • 10/28/2020
A memory initialization issue was addressed with improved memory handling. This issue is fixed in macOS Mojave 10.14.4, Security Update 2019-002 High Sierra, Security Update 2019-002 Sierra, iOS 12.1.1, watchOS 5.1.2, macOS Mojave 10.14.2, Security Update 2018-003 High Sierra, Security Update 2018-006 Sierra, tvOS 12.1.1. A local user may be able to read kernel memory.
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Analysis
by VulDB Data Team • 11/27/2020
This vulnerability represents a critical memory initialization flaw that existed within Apple's operating system kernels across multiple platforms including macOS, iOS, watchOS, and tvOS. The issue stems from inadequate memory handling during kernel initialization processes, creating potential pathways for unauthorized memory access. The vulnerability affects systems running versions prior to the respective security updates, with specific fixes released for macOS Mojave 10.14.4, Security Update 2019-002 High Sierra, Security Update 2019-002 Sierra, iOS 12.1.1, watchOS 5.1.2, macOS Mojave 10.14.2, Security Update 2018-003 High Sierra, Security Update 2018-006 Sierra, and tvOS 12.1.1. The flaw allows local attackers with user-level privileges to potentially read kernel memory contents, which could expose sensitive system information and potentially lead to privilege escalation or further exploitation.
The technical nature of this vulnerability aligns with CWE-128, which addresses "Wrap or Overflow" conditions in memory management, and more specifically relates to improper initialization of memory regions within kernel space. When kernel memory is not properly initialized before use, it can contain residual data from previous operations, creating information leakage opportunities. This type of vulnerability falls under the ATT&CK framework's T1003.001 technique for "OS Credential Dumping" and T1059.001 for "Command and Scripting Interpreter" as attackers could potentially use the leaked kernel memory information to discover system state or credentials. The memory initialization issue creates a persistent vulnerability where uninitialized memory regions may contain exploitable data that could be accessed through kernel memory read operations.
The operational impact of CVE-2018-4448 extends beyond simple information disclosure, as kernel memory access can reveal critical system information including process memory layouts, cryptographic keys, or other sensitive data structures. Local users who can execute code on affected systems can leverage this vulnerability to gain insights into system internals that could aid in more sophisticated attacks. Attackers might use this information to bypass security controls, identify system weaknesses, or develop targeted exploits against other vulnerabilities. The impact is particularly concerning in enterprise environments where macOS and iOS devices may be running vulnerable versions, potentially exposing corporate networks to advanced persistent threats. Additionally, the cross-platform nature of the vulnerability means that organizations must ensure all affected devices across their infrastructure receive timely updates.
Organizations should implement immediate mitigation strategies including mandatory deployment of the applicable security updates across all affected platforms, as specified in the vulnerability announcement. System administrators should prioritize patching efforts for macOS Mojave 10.14.4, Security Update 2019-002 High Sierra, Security Update 2019-002 Sierra, iOS 12.1.1, watchOS 5.1.2, macOS Mojave 10.14.2, Security Update 2018-003 High Sierra, Security Update 2018-006 Sierra, and tvOS 12.1.1. Network monitoring should be enhanced to detect potential exploitation attempts, and access controls should be reviewed to limit local user privileges where possible. The vulnerability demonstrates the importance of proper memory initialization practices in kernel code development and highlights the need for comprehensive security testing of system components before deployment. Regular vulnerability assessments and security audits should be conducted to identify similar memory handling issues that could exist in other system components or third-party applications.