DUHK attack is a combination of two main factors, including the use of the ANSI X9.31 Random Number Generator (RNG) and hardcoded “seed key”” The attack is not trivial as an attacker using a modern computer can recover the encryption key in around four minutes per connection. Fortinet FortiGate devices using FortiOS 4.3.0 to 4.18 are vulnerable to DUHK attacks (CVE-2016-8492) FortiOS 5.x is not affected
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