PSIRT Advisory

FortiOS SSL Deep Inspection TLS Padding Oracle Vulnerabilities

Summary

Multiple padding Oracle vulnerabilities (Zombie POODLE, GOLDENDOODLE, OpenSSL 0-length) in the CBC padding implementation of FortiOS when configured with SSL Deep Inspection policies and with the IPS sensor enabled may allow an attacker to decipher TLS connections going through the FortiGate by monitoring the traffic (should he/she be able to).

Impact

Information Disclosure

Affected Products

FortiOS when using the following IPS Engine versions:

IPS engine version 5.00000 to 5.00006

IPS engine version 4.00000 to 4.00036

IPS engine version 4.00200 to 4.00219

IPS engine version 3.00547 and below

Solutions

Update to IPS engine 3.00548, 4.00037,  5.00007 or above.

Specifically:

IPS Engine 3.00548 (or above) for the FortiOS 5.6 branch and branches below
IPS Engine 4.00037 (or above) for the ForitOS 6.0 branch
IPS Engine 5.00007 (or above) for the FortiOS 6.2 branch

An IPS Engine that includes the fix is built-in FortiOS 5.6.11, 6.0.9 and 6.2.1, and versions above in those respective branches.

To check for the FortiOS IPS engine version: 

* From the admin CLI console:

run command "diag autoupdate versions"

IPS Attack Engine

Version: x.xxxxx

* From the admin webUI:

System->FortiGuard->IPS Engine->Version x.xxxxx

For the IPS engine and FortiOS version compatibility chart, please refer the following link:

https://pub.kb.fortinet.com/ksmcontent/Fortinet-Public/current/FortiGate_6_0/fortios-fortiaps-ips-av-compatibility.pdf

Revision History:
07-23-2019 Initial version
02-25-2020 Added FortiOS versions with built-in IPS Engines.