Open redirect and XSS in FortiOS - CVE-2016-3978

Detailed vulnerability description

The vulnerability allows a remote attacker to redirect victims to malicious website or perform cross-site scripting attacks.

The vulnerability is caused by incorrect filtration of user-input passed via the "redir" HTTP GET parameter to "/login" page. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in victim’s browser in security context of vulnerable website or redirect victim to arbitrary 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.

How to mitigate CVE-2016-3978

Sources

• https://fortiguard.com/advisory/fortios-open-redirect-vulnerability
• http://www.behindthefirewalls.com/2016/05/CVE-2016-3978-open-redirect-and-xss-in-fortinet.html