MitM attack in Fortinet Forticlient

1) Improper validation of certificate with host mismatch

EUVDB-ID: #VU47108

Risk: High

CVSSv3.1: 9.1 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N/E:U/RL:U/RC:C]

CVE-ID: N/A

CWE-ID: CWE-297 - Improper Validation of Certificate with Host Mismatch

Exploit availability: No

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.

Mitigation

Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

Vulnerable software versions

Fortinet FortiClient for Windows: 0 - 6.4.0

External links

http://securingsam.com/breaching-the-fort/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.