CVE-2018-4005 in VPN
Summary
by MITRE
An exploitable privilege escalation vulnerability exists in the Shimo VPN 4.1.5.1 helper service in the configureRoutingWithCommand function. A user with local access can use this vulnerability to raise their privileges to root. An attacker would need local access to the machine for a successful exploit.
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Analysis
by VulDB Data Team • 08/29/2023
The CVE-2018-4005 vulnerability represents a critical privilege escalation flaw within the Shimo VPN 4.1.5.1 helper service that operates with elevated privileges on macOS systems. This vulnerability specifically resides in the configureRoutingWithCommand function, which serves as a critical interface for network routing configuration. The flaw stems from improper input validation and privilege handling within the helper service mechanism, creating a pathway for local users to exploit system protections and elevate their access rights to root level. The vulnerability's existence in a privileged helper service demonstrates a fundamental security weakness in the application's design where user-controlled inputs are processed without adequate sanitization or privilege separation.
The technical implementation of this vulnerability exploits the inherent trust model of macOS helper services, where applications can delegate specific privileged operations to background processes. When the configureRoutingWithCommand function processes user-supplied commands, it fails to properly validate or sanitize the input parameters before executing system-level operations. This allows a local attacker to inject malicious commands that are then executed with root privileges by the helper service. The vulnerability is particularly concerning because it requires only local access to the machine, meaning any user with login credentials can potentially exploit this flaw without requiring network access or additional attack vectors. This type of vulnerability aligns with CWE-78, which describes improper neutralization of special elements used in OS commands, and represents a classic privilege escalation attack pattern.
The operational impact of CVE-2018-4005 extends beyond simple privilege escalation as it fundamentally undermines the security model of macOS systems. Once an attacker achieves root access through this vulnerability, they can bypass all system protections including file permissions, user access controls, and application sandboxing mechanisms. The exploitation process typically involves crafting specific input parameters that cause the helper service to execute unintended system commands, potentially allowing for complete system compromise. This vulnerability affects organizations that deploy Shimo VPN software as it creates an attack surface where local users can gain administrative control over systems. The impact is particularly severe in enterprise environments where VPN clients are commonly used and where a single compromised local account could provide attackers with persistent root access to critical infrastructure.
Mitigation strategies for CVE-2018-4005 should focus on both immediate remediation and long-term architectural improvements. The most effective immediate solution involves updating to a patched version of Shimo VPN that properly validates input parameters and implements proper privilege separation in the helper service. Organizations should also consider disabling unnecessary helper services or implementing additional security controls such as macOS System Integrity Protection (SIP) enforcement and monitoring for unauthorized helper service usage. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques using service binary modification and legitimate system tools, making it particularly challenging to detect through traditional security controls. Regular security assessments should include verification of helper service configurations and input validation mechanisms to prevent similar vulnerabilities from being introduced in future software versions. The vulnerability underscores the importance of secure coding practices and proper privilege management in macOS applications, particularly those that interact with system-level operations through helper services.