The Firewalls’ backdoor saga: Fortinet under fire

Do you remember that less than a month ago Juniper Networks was in the limelight for its backdoor in ScreenOS software? A lot of speculation was done on the case and probably the NSA was involved at some point 🙂 .

On Saturday 9th January 2016 an anonymous user sent the following email to the Full Disclosure mailing list:

SSH Backdoor for FortiGate OS Version 4.x up to 5.0.7
From: <operator8203 () runbox com>
Date: Sat, 09 Jan 2016 14:48:01 -0500 (EST)

The above Python script allows to interact  with the hardware firewall via SSH using username “Fortimanager_Access” and a dynamically generated password (a hashed version of the “FGTAbc11*xy+Qqz27” password string). Both username and passwords are hardcoded in the FortiGate firmware.

Someone tried to verify the vulnerability and apparently it works:


According to the anonymous poster and a few other security researchers, Dr David D. Davidson included, this can be considered a real backdoor at the end of the day, even if FortiNet has another opinion on the case.


Fortinet published an article in which it claims that the aforementioned thing represented a vulnerability indeed but it wasn’t intended as a “backdoor”, but rather a “management authentication issue”. Apparently the SSH user was created for challenge-and-response authentication routine for logging into Fortinet’s servers with the secure shell (SSH) protocol. (A SSH user with administrative access).

Even if Fortinet was “innocent”, that wasn’t surely a good idea. A poor implementation based on security through obscurity that eventually was made public and could have been already used in the wild.

To say the truth this isn’t a 0day but rather an olday, like it was defined by someone 🙂 Fortinet says that the vulnerability made public is related to CVE-2014-2216 and a newer version that addressed the vulnerability was released without informing the end users of the “issue”.


A quick search on Shodan shows the following:


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If you are using FortiOS branch 4.3 upgrade to FortiOS 4.3.17 or later.
In case you are using FortiOS branch 5.0 upgrade to FortiOS 5.0.8 or later.


* Disable admin access via SSH on all interfaces, and use the Web GUI instead, or the console applet of the GUI for CLI access.

* If SSH access is mandatory, in 5.0 one can restrict access to SSH to a minimal set of authorized IP addresses, via the Local In policies.

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Author: Fabio Baroni   Date: 2016-01-13 12:36:56

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