FortiOS malformed HTTP or SSL/TLS traffic control
FortiOS Explicit Web Proxy by default allows non-standard HTTP traffic.
FortiOS SSL/SSH Inspection Profile by default allows non-standard SSL/TLS traffic.
Operational Risk, Traffic Bypass
By default, this possible operational risk is applicable to all FortiOS versions.
Non standard HTTP traffic can be disallowed with the following CLI commands:
config web-proxy global
set tunnel-non-http disable (default value "enable")
Non standard SSL/TLS traffic can be disallowed with the following CLI commands:
config firewall ssl-ssh-profile
set ports [port]
set unsupported-ssl block (default value "bypass")
Starting from 6.2.1, FortiOS allows administrators to disallow both via the admin WebUI as well:
For Explicit Web Proxy: Network -> Explicit Proxy -> Protocol Enforcement (default is off)
For SSL/SSH Inspection: Security Profiles -> SSL/SSH Inspection ->Enforce SSL Protocol Compliance (default is off)
Fortinet thank security research company Praetorian bringing this attention to us with certain proofs.