D(HE)at Attack – 20-Yr-old Flaw Let Attackers Exploit Diffie-Hellman Protocol To Over-Heat Your CPU

Researchers uncovered a new type of denial-of-service (DoS) attack, known as the D(HE)at attack, exploits the computational demands of the Diffie-Hellman key agreement protocol, particularly its ephemeral variant (DHE), to overwhelm servers with minimal effort from the attacker.

The attack is named for its ability to overheat the CPU by making the victim perform the heavy computation of modular exponentiation, which is used in the Diffie-Hellman key exchange within cryptographic protocols like TLS, SSH, IPsec, and OpenVPN.

Here’s a detailed look at how this attack works and its implications.