CVE-2019-8454 in Endpoint Security
Summary
by MITRE
A local attacker can create a hard-link between a file to which the Check Point Endpoint Security client for Windows before E80.96 writes and another BAT file, then by impersonating the WPAD server, the attacker can write BAT commands into that file that will later be run by the user or the system.
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Analysis
by VulDB Data Team • 09/11/2023
The vulnerability identified as CVE-2019-8454 represents a critical local privilege escalation and persistence mechanism within Check Point Endpoint Security client for Windows versions prior to E80.96. This flaw exploits the client's handling of file operations and network configuration processes, creating a dangerous attack surface that allows adversaries to execute malicious code with elevated privileges. The vulnerability specifically targets the Windows operating system's interaction with the Web Proxy Auto-Discovery (WPAD) protocol, which is used by clients to automatically configure proxy settings. The attack vector relies on the attacker's ability to manipulate file system permissions and network communications to establish a malicious execution chain.
The technical implementation of this vulnerability stems from insufficient input validation and improper file handling within the Check Point client software. When the client processes network configuration updates, it creates temporary files in predictable locations that can be manipulated by local attackers. The flaw occurs because the system does not properly validate file ownership or permissions when processing WPAD responses, allowing a malicious actor to create symbolic or hard links between sensitive files and arbitrary batch files. This creates a condition where legitimate system processes can execute attacker-controlled code when they attempt to write to what they believe is a legitimate configuration file. The vulnerability is classified under CWE-59, which addresses improper link handling, and represents a classic example of a privilege escalation through file system manipulation.
The operational impact of CVE-2019-8454 extends beyond simple code execution to encompass persistent system compromise and potential lateral movement within network environments. Once successfully exploited, the attacker can establish a foothold that persists across system reboots and can be used to maintain access to the compromised endpoint. The attack requires local system access initially, but can be leveraged to create more sophisticated persistence mechanisms through the Windows startup processes or scheduled tasks. The vulnerability is particularly dangerous in enterprise environments where Check Point clients are deployed, as it allows attackers to bypass traditional security controls and execute commands with the privileges of the affected user or system. This attack pattern aligns with ATT&CK technique T1059.001 for command and scripting interpreter, and T1068 for local privilege escalation, making it a significant threat to organizations relying on endpoint security solutions.
Mitigation strategies for CVE-2019-8454 require both immediate patching and operational security improvements. Organizations should prioritize updating all Check Point Endpoint Security clients to version E80.96 or later, which contains the necessary fixes for this vulnerability. Additionally, network administrators should implement strict controls over WPAD server configurations and consider disabling automatic proxy configuration where possible. System hardening measures including restricting local file system permissions, monitoring for suspicious file link creation, and implementing application whitelisting can significantly reduce the attack surface. The vulnerability demonstrates the importance of secure file handling practices and proper privilege separation in security software implementations. Network segmentation and monitoring for unusual WPAD-related network traffic can help detect exploitation attempts, while regular security assessments should verify that no malicious files have been created or modified on affected systems. Organizations should also consider implementing endpoint detection and response solutions to identify and block suspicious file manipulation activities that could indicate exploitation attempts.