What type of attack is being performed when an attacker intercepts the initial communications between a Web server and a Web browser while forcing a vulnerable server to insecurely renegotiate the encryption being used down to a weaker cipher?

a ciphertext-only attack

Explanation:

Based on the scenario being described within the question it can be said that the type of attack being performed is known as a ciphertext-only attack . This is an attack model in which the attacker in which the attacker gains access to one set of ciphertexts with the main goal of forcing the server to renegotiate the encryption being used down to a weaker cipher and hopefully deducing the plaintexts or even the key.

whats

the answer to your question would be something called hertz. the unit of measurement called a hertz, which is one cycle per second, is used to measure clock speed. within one cycle, your computer processes, refreshes, or updates itself to the changes that it is going through. in the case of computer clock speed, one hertz equals one tick per second. the clock speed of computers is usually measured in megahertz (mhz) or gigahertz (ghz)