CVE-2019-17658 in FortiClient
Summary
by MITRE
An unquoted service path vulnerability in the FortiClient FortiTray component of FortiClientWindows v6.2.2 and prior allow an attacker to gain elevated privileges via the FortiClientConsole executable service path.
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Analysis
by VulDB Data Team • 05/12/2022
The vulnerability identified as CVE-2019-17658 represents a critical privilege escalation flaw within the FortiClient Windows endpoint protection suite, specifically affecting versions up to and including v6.2.2. This issue resides within the FortiTray component, which serves as a system tray utility that manages various FortiClient functions and interacts with the Windows service management system. The vulnerability stems from improper handling of service path specifications, creating a path traversal opportunity that can be exploited by malicious actors to execute arbitrary code with elevated privileges.
The technical flaw manifests as an unquoted service path configuration in the FortiClientConsole executable service path. When Windows services are configured without proper quotation around paths containing spaces, the operating system searches for executables in a predictable order based on the path components. This behavior creates a directory traversal vulnerability where an attacker can place a malicious executable in a directory that appears earlier in the search path than the legitimate FortiClientConsole binary. The vulnerability maps to CWE-428, which specifically addresses "Unquoted Service Path" issues in Windows service configurations, where service paths containing spaces are not properly quoted, allowing for path injection attacks.
The operational impact of this vulnerability is severe and directly relates to the principle of least privilege violations in Windows security models. An attacker with standard user privileges can exploit this vulnerability to execute code with system-level privileges, effectively bypassing the standard security boundaries that protect Windows systems. This privilege escalation allows for complete system compromise, enabling attackers to install backdoors, exfiltrate data, or establish persistent access to the compromised system. The vulnerability is particularly concerning because FortiClient is commonly deployed in enterprise environments where it typically runs with elevated privileges to perform its security functions, making the attack surface even more critical.
The exploitation of this vulnerability aligns with several tactics outlined in the MITRE ATT&CK framework, specifically covering techniques related to privilege escalation and persistence. Attackers can leverage this vulnerability as part of a broader attack chain, using the elevated privileges to establish further footholds within the network. The vulnerability also intersects with ATT&CK technique T1059, which covers command and scripting interpreter usage, as attackers may use the elevated privileges to execute malicious scripts or binaries. Organizations deploying FortiClient should prioritize immediate patching of affected versions, as the vulnerability provides a straightforward path to system compromise. Security teams should also implement monitoring for suspicious service path modifications and conduct regular audits of service configurations to identify and remediate similar unquoted path vulnerabilities across their Windows infrastructure. Additionally, this vulnerability highlights the importance of proper service path quoting practices during software installation and configuration, which should be enforced through security guidelines and automated configuration management tools to prevent similar issues in other software components.