CVE-2018-4276 in macOS
Summary
by MITRE
A null pointer dereference was addressed with improved validation. This issue affected versions prior to macOS High Sierra 10.13.6.
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Analysis
by VulDB Data Team • 08/21/2023
The vulnerability identified as CVE-2018-4276 represents a critical null pointer dereference flaw that existed in macOS versions prior to High Sierra 10.13.6. This type of vulnerability falls under the broader category of memory safety issues and is particularly dangerous because it can lead to system instability and potential exploitation by malicious actors. The issue stems from inadequate input validation within the operating system's kernel components, specifically affecting the way the system handles certain memory references during processing operations.
The technical nature of this flaw involves a situation where the operating system attempts to access a memory location that has not been properly initialized or allocated, resulting in a null pointer dereference. When such an operation occurs in kernel space, it can cause the entire system to crash or become unresponsive, creating a denial of service condition that severely impacts system availability. This vulnerability is classified under CWE-476 which specifically addresses null pointer dereference conditions in software systems. The flaw manifests when legitimate system operations encounter unexpected null values in memory pointers, causing the kernel to fail gracefully rather than handling the error condition properly.
From an operational perspective, this vulnerability presents significant risks to macOS environments that have not been updated to the patched version. Attackers could potentially exploit this condition to cause system crashes or, more critically, to execute arbitrary code through carefully crafted inputs that trigger the null pointer dereference. The impact extends beyond simple system instability as it could allow unauthorized users to gain elevated privileges or disrupt critical services running on affected systems. The vulnerability is particularly concerning in enterprise environments where macOS systems serve as servers or critical infrastructure components, as it could be leveraged to create persistent denial of service conditions that impact business operations.
The mitigation strategy for CVE-2018-4276 primarily involves applying the official security update released by Apple for macOS High Sierra 10.13.6, which includes improved validation mechanisms to prevent the null pointer dereference condition. System administrators should prioritize patching affected systems and implement comprehensive monitoring to detect any exploitation attempts. The fix addresses the root cause by implementing proper null checks and validation procedures within the kernel components that were previously vulnerable. Organizations should also consider implementing additional security controls such as kernel extension restrictions and monitoring for unusual system behavior that might indicate exploitation attempts, aligning with the defensive measures recommended in the mitre ATT&CK framework for operating system exploitation techniques. Regular vulnerability assessments and patch management procedures should be maintained to ensure all systems remain protected against similar memory safety issues.