CVE-2018-7687 in Client for OES
Summary
by MITRE
The Micro Focus Client for OES before version 2 SP4 IR8a has a vulnerability that could allow a local attacker to elevate privileges via a buffer overflow in ncfsd.sys.
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Analysis
by VulDB Data Team • 03/14/2023
The vulnerability identified as CVE-2018-7687 affects the Micro Focus Client for OES version 2 SP4 IR8a and earlier releases, presenting a critical security risk that enables local privilege escalation through a buffer overflow condition within the ncfsd.sys kernel driver. This flaw resides in the network file system driver component that manages file operations within the operating environment, making it a significant target for attackers seeking to gain elevated system privileges. The vulnerability specifically manifests in the ncfsd.sys module which handles network file system operations and is susceptible to malformed input that exceeds allocated buffer boundaries.
The technical implementation of this buffer overflow vulnerability stems from inadequate input validation within the kernel-mode driver component. When the ncfsd.sys driver processes specific network file system requests, it fails to properly validate the length of incoming data structures, allowing an attacker to provide input that exceeds the allocated buffer space. This condition creates a memory corruption scenario where adjacent memory locations become overwritten, potentially allowing an attacker to manipulate kernel memory structures and execute arbitrary code with system-level privileges. The vulnerability operates at the kernel level, making it particularly dangerous as it bypasses user-mode security controls and operates with the highest privilege level available to the system.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with complete control over the affected system. Local attackers who can execute code on the target machine can leverage this vulnerability to gain SYSTEM-level privileges, enabling them to modify system files, install malware, create new user accounts, or establish persistent backdoors. The attack surface is relatively narrow since it requires local access to the system, but the privilege escalation capability makes it highly valuable for attackers who have already established a foothold. This vulnerability directly maps to CWE-121, which describes heap-based buffer overflow conditions, and aligns with ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation' through kernel exploits.
Mitigation strategies for CVE-2018-7687 should prioritize immediate patch deployment from Micro Focus, as the vendor has released updates addressing this specific vulnerability in version 2 SP4 IR8a and subsequent releases. Organizations should implement comprehensive patch management procedures to ensure all affected systems receive the necessary updates promptly. Additionally, system administrators should consider implementing additional security controls such as kernel patch protection mechanisms, driver signature enforcement, and monitoring for suspicious kernel-mode activities. Network segmentation and access controls should be maintained to limit local access privileges, reducing the potential attack surface for this type of vulnerability. The vulnerability also highlights the importance of regular security assessments of kernel-mode components and proper input validation practices in system drivers to prevent similar issues from arising in the future.