Vulnerability identifier: #VU9503

Vulnerability risk: Low

CVSSv3.1: 4.7 [CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-14186

CWE-ID: CWE-79

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
FortiOS
Operating systems & Components / Operating system

Vendor: Fortinet, Inc

Description

Vulnerability allows a remote authenticated attacker to perform XSS attacks.

The vulnerability is caused by an input validation error in Fortinet FortiOS 5.6.0 to 5.6.2, 5.4.0 to 5.4.6, 5.2.0 to 5.2.12, 5.0 and below versions under SSL VPN web portal when processing the login "redir" parameter. A remote authenticated attacker can trick the victim to follow a specially specially crafted link and execute arbitrary HTML and script code in victim's browser in security context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

Mitigation
Update to FortiOS 5.6.8, 6.0.5 or 6.2.0.

Vulnerable software versions

FortiOS: 5.6.0 - 5.6.7, 5.4.0 - 5.4.6, 5.2.0 - 5.2.12, 5.0.0 - 5.0.13, 4.3.0 - 4.3.16, 6.0.0 - 6.0.4

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External links
http://fortiguard.com/psirt/FG-IR-17-242

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

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