#VU9124 Cross-site scripting in FortiOS - CVE-2017-7739

Vulnerability identifier: #VU9124

Vulnerability risk: Low

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Clear]

CVE-ID: CVE-2017-7739

CWE-ID: CWE-79

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
FortiOS
Operating systems & Components / Operating system

Vendor: Fortinet, Inc

Description

The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists in the web proxy disclaimer response pages due to insufficient sanitization of user-supplied data. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in 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 version 5.2.12, 5.4.6, 5.6.1.

Vulnerable software versions

FortiOS: 5.2.0 - 5.2.11, 5.4.0 - 5.4.5, 5.6.0

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External links
https://fortiguard.com/psirt/FG-IR-17-168

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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?

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