Improper validation of certificate with host mismatch in Fortinet FortiClient for Windows - #VU47108
Published: September 25, 2020
Vulnerability identifier: #VU47108
CSH Severity: High
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Amber
CVE-ID: N/A
CWE-ID: CWE-297
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
Fortinet FortiClient for Windows
Fortinet FortiClient for Windows
Software vendor:
Fortinet, Inc
Fortinet, Inc
Description
The vulnerability allows a remote attacker to perform a MitM attack.
The vulnerability exists in FortiClient SSL-VPN client due to the application does not properly validate server certificates and checks only if the certificate was issued by a trusted CA or Fortinet itself. A remote attacker can supply a certificate, issued to a different Fortigate router and perform a Man-in-the-Middle attack.
Successful exploitation of the vulnerability may allow an attacker to intercept and descrypt all traffic, protected with Fortinet SSL-VPN.
Remediation
Cybersecurity Help is currently unaware of any official solution to address this vulnerability.