CVE-2017-2494 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.12.5 is affected. The issue involves the "Kernel" component. It allows attackers to execute arbitrary code in a privileged context or cause a denial of service (memory corruption) via a crafted app.
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Analysis
by VulDB Data Team • 12/24/2020
This vulnerability resides within Apple's kernel component affecting macOS versions prior to 10.12.5, representing a critical privilege escalation flaw that enables attackers to execute arbitrary code with elevated privileges. The issue stems from improper memory management within the kernel's handling of crafted applications, creating a pathway for malicious actors to bypass system security controls and operate at the highest privilege level. The vulnerability specifically manifests through memory corruption that occurs when the kernel processes specially crafted applications, allowing attackers to manipulate kernel memory structures and potentially execute malicious code with system-level privileges. This flaw directly impacts the fundamental security model of macOS by undermining the privilege separation mechanisms that protect the kernel from user-space applications. The vulnerability has been categorized under CWE-119 as a weakness involving memory corruption, specifically related to improper handling of memory access within kernel space. From an operational perspective, this vulnerability represents a severe threat to macOS systems since it allows attackers to gain root access without requiring user interaction or prior exploitation of other vulnerabilities. The attack vector requires only a crafted application that, when executed, triggers the kernel memory corruption, making it particularly dangerous as it can be delivered through seemingly legitimate software or malicious applications. The potential impact extends beyond simple privilege escalation to include complete system compromise, data exfiltration, and persistent backdoor installation. The vulnerability's exploitation can result in both remote code execution and local privilege escalation, making it a prime target for advanced persistent threats. Security researchers have noted that this flaw demonstrates a classic buffer overflow or memory corruption pattern that allows attackers to manipulate kernel execution flow and gain unauthorized access to system resources. The issue aligns with ATT&CK technique T1068 which describes the use of local privilege escalation to gain system-level access. Organizations running affected macOS versions face significant risk exposure as this vulnerability can be exploited without user interaction, making it particularly dangerous in enterprise environments where system integrity is paramount.
The technical implementation of this vulnerability involves the kernel's failure to properly validate memory operations when processing crafted applications, creating opportunities for attackers to manipulate kernel data structures and execute malicious code with kernel privileges. The flaw specifically relates to how the kernel handles memory allocation and deallocation during application processing, where insufficient bounds checking allows attackers to overwrite critical kernel memory regions. This memory corruption vulnerability can be exploited through various methods including stack smashing, heap manipulation, or direct memory pointer manipulation that causes the kernel to execute attacker-controlled code. The exploitation process typically involves crafting a malicious application that, when loaded and executed, triggers the memory corruption condition within kernel space. The vulnerability's impact is amplified by the fact that kernel-level code execution provides attackers with complete system control, including access to all user data, network communications, and system resources. The memory corruption occurs at a fundamental level where the kernel's memory management subsystem fails to properly enforce access controls and memory boundaries, allowing user-space applications to corrupt kernel memory structures. This represents a breakdown in the kernel's memory safety mechanisms that should normally prevent user applications from directly manipulating kernel data. The vulnerability's classification under CWE-119 indicates it involves memory access violations that can lead to arbitrary code execution in privileged contexts, making it a serious concern for system security. From a defensive standpoint, this vulnerability highlights the importance of kernel security and the critical need for proper memory management practices in system-level code. The flaw demonstrates how insufficient input validation and memory safety checks in kernel components can create severe security implications that affect the entire operating system's integrity.
Mitigation strategies for this vulnerability require immediate patching of affected macOS systems to version 10.12.5 or later, which contains the necessary kernel security fixes. Organizations should implement comprehensive patch management processes to ensure all macOS systems are updated promptly, as this vulnerability can be exploited remotely without user interaction. System administrators should also monitor for suspicious application execution and implement application whitelisting policies to prevent exploitation of this vulnerability through malicious applications. The vulnerability's nature makes it particularly dangerous in enterprise environments where multiple systems may be running affected versions, requiring coordinated patching efforts across all affected devices. Network segmentation and monitoring solutions should be deployed to detect potential exploitation attempts, as the vulnerability can be triggered through legitimate application execution. Additional defensive measures include implementing kernel extension restrictions and monitoring for unusual kernel memory access patterns that might indicate exploitation attempts. Security teams should also consider implementing behavioral analysis tools that can detect anomalous kernel activity indicative of memory corruption exploitation. The vulnerability's impact on system integrity underscores the importance of maintaining up-to-date security patches and implementing layered security controls. Organizations should also review their application deployment processes to ensure only trusted applications are executed on systems, as the vulnerability can be exploited through malicious applications. The fix for this vulnerability involves kernel-level memory management improvements and enhanced validation of memory operations during application processing, addressing the root cause of the memory corruption issue. Regular security assessments and vulnerability scanning should be performed to identify systems running affected macOS versions and ensure proper remediation. The vulnerability serves as a reminder of the critical importance of kernel security and the need for robust memory safety practices in system-level code development.