DUHK Attack Lets Hackers Recover Encryption Key Used in VPNs & Web Sessions

DUHK — Don't Use Hard-coded Keys — is a new 'non-trivial' cryptographic implementation vulnerability that could allow attackers to recover encryption keys that secure VPN connections and web browsing sessions.

DUHK is the third crypto-related vulnerability reported this month after KRACK Wi-Fi attack and ROCA factorization attack.

The vulnerability affects products from dozens of vendors, including Fortinet, Cisco, TechGuard, whose devices rely on ANSI X9.31 RNG — an outdated pseudorandom number generation algorithm — 'in conjunction with a hard-coded seed key.'

Pseudorandom number generators (PRNGs) don’t generate random numbers at all. Instead, it is a deterministic algorithm that produces a sequence of bits based on initial secret values called a seed and the current state. It always generates the same sequence of bits for when used with same initial values.