CVE-2016-8493 in FortiClient
Summary
by MITRE
In FortiClientWindows 5.4.1 and 5.4.2, an attacker may escalate privilege via a FortiClientNamedPipe vulnerability.
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Analysis
by VulDB Data Team • 05/12/2022
The vulnerability identified as CVE-2016-8493 represents a critical privilege escalation flaw within FortiClient Windows versions 5.4.1 and 5.4.2, specifically targeting the FortiClientNamedPipe component. This issue stems from improper access control mechanisms implemented in the named pipe communication interface used by the FortiClient security application. The vulnerability allows unprivileged attackers to exploit a weakness in the pipe access permissions, potentially enabling them to execute arbitrary code with elevated privileges. The flaw exists in the Windows named pipe security model implementation where the FortiClient service fails to properly validate access rights when processing incoming requests through the named pipe interface.
The technical exploitation of this vulnerability involves an attacker creating a malicious named pipe connection that mimics legitimate FortiClient service communications. The vulnerability is categorized under CWE-264, which addresses permissions, privileges, and access control issues, specifically focusing on inadequate protection of named pipes. This weakness in the security model allows an attacker to bypass normal access restrictions and gain elevated privileges through the FortiClient service process. The vulnerability demonstrates a classic privilege escalation vector where a local attacker with minimal privileges can leverage the service's trust relationship to execute code with SYSTEM level privileges, effectively compromising the entire system.
From an operational perspective, this vulnerability poses significant risk to enterprise environments where FortiClient is deployed as a security solution. The impact extends beyond individual system compromise to potentially enable attackers to establish persistent backdoors, escalate privileges across network segments, and access sensitive corporate data. The vulnerability is particularly dangerous because it leverages the legitimate FortiClient service process, making detection more challenging for security monitoring systems. Attackers can exploit this weakness to bypass traditional security controls and gain unauthorized access to protected resources, potentially leading to data breaches, lateral movement, and extended persistence within the network infrastructure.
Organizations should implement immediate mitigations including applying the vendor-provided security patches released by Fortinet to address this vulnerability. System administrators should also consider implementing additional security controls such as restricting access to named pipes through Windows registry modifications and monitoring for suspicious named pipe activity. The mitigation strategy should align with ATT&CK framework technique T1068, which covers privilege escalation through local exploits, and T1059, covering execution through command and scripting interpreters. Security teams should also implement network monitoring to detect unusual named pipe communications and consider implementing principle of least privilege controls for FortiClient service accounts to minimize potential impact from such vulnerabilities.