CVE-2015-5893 in Mac OS X
Summary
by MITRE
SMBClient in SMB in Apple OS X before 10.11 allows local users to obtain sensitive kernel memory-layout information via unspecified vectors.
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Analysis
by VulDB Data Team • 11/21/2024
The vulnerability identified as CVE-2015-5893 represents a significant information disclosure issue within Apple's operating system implementation of the Server Message Block protocol. This flaw exists in SMBClient components of OS X versions prior to 10.11, where local attackers can exploit unspecified vectors to extract sensitive kernel memory layout information. The vulnerability stems from insufficient access controls and memory protection mechanisms within the SMB implementation, allowing unauthorized local users to gain insights into the kernel's memory structure that could be leveraged for more sophisticated attacks.
The technical nature of this vulnerability aligns with CWE-200, which encompasses information disclosure weaknesses in software implementations. The flaw operates at the kernel level within the SMB subsystem, where proper memory management and access control mechanisms fail to prevent local users from accessing kernel memory addresses and layout information. This type of information disclosure represents a critical security concern as it provides attackers with detailed knowledge of the system's internal memory organization, potentially enabling them to craft more effective exploitation techniques for subsequent attacks. The unspecified vectors suggest that multiple pathways within the SMBClient implementation could be exploited, making the vulnerability particularly concerning from a defensive standpoint.
From an operational impact perspective, this vulnerability significantly weakens the security posture of affected systems by providing local attackers with kernel memory layout information that could facilitate advanced exploitation techniques. The ability to obtain such sensitive information undermines the fundamental security model of modern operating systems, where kernel memory protection mechanisms are designed to prevent unauthorized access to critical system information. Attackers could potentially use this information to bypass kernel address space layout randomization defenses, making subsequent exploits more reliable and effective. The local nature of the vulnerability means that any user with access to the system could potentially exploit it, making it particularly dangerous in multi-user environments or when systems are compromised through other attack vectors.
The recommended mitigations for CVE-2015-5893 primarily focus on updating to Apple OS X 10.11 or later versions where the vulnerability has been addressed through proper kernel memory protection mechanisms and access controls. System administrators should prioritize patch management to ensure all affected systems receive the necessary security updates. Additional defensive measures include implementing strict access controls and monitoring for unusual memory access patterns, though these approaches are secondary to the primary remediation of updating to patched versions. Organizations should also consider implementing network segmentation and monitoring to limit potential exploitation opportunities, as the vulnerability requires local system access to exploit. The remediation process should include thorough testing of patches in controlled environments before widespread deployment to ensure compatibility with existing system configurations and applications.