Vulnerability identifier: #VU31052

Vulnerability risk: High

CVSSv3.1: 8.4 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2018-13383

CWE-ID: CWE-119

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
FortiOS
Operating systems & Components / Operating system

Vendor: Fortinet, Inc

Description

The vulnerability allows a remote non-authenticated attacker to compromise the affected system.

The vulnerability exists due to a boundary error when parsing web pages in the SSL VPN web portal. A remote attacker can create a specially crafted web page with malicious javascript href data, trick the authenticated user to visit it, trigger a buffer overflow and execute arbitrary code on the system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

FortiOS: 6.0.0 - 6.0.4

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External links
http://www.securityfocus.com/bid/108539
http://devco.re/blog/2019/08/09/attacking-ssl-vpn-part-2-breaking-the-Fortigate-ssl-vpn/
http://fortiguard.com/advisory/FG-IR-18-388
http://i.blackhat.com/USA-19/Wednesday/us-19-Tsai-Infiltrating-Corporate-Intranet-Like-NSA.pdf

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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?

Yes. This vulnerability is being exploited in the wild.