How 1 cpu 1 vote works? What is its validity? Does it use IP address or mac address or similar to that? If yes, then it can be changed and can make fool to the network. If it can't, then how is it preventing any malicious activity?
one-cpu one-vote is about Proof of Work. Except it really is not a vote and "votes" aren't being recorded as to which CPU they came from.
What it really means is that if you participate in mining (so you are performing Bitcoin's Proof of Work), you have the ability to decide which blockchain is "the blockchain" in the even that there are multiple valid blockchains. How this works is that a miner chooses a block to build their block on top of, and they dedicate their computing power to extend that blockchain. The blockchain that "wins the vote" is the blockchain that has the most cumulative Proof of Work, which is generally the one that the most miners have decided to mine on top of.
There is no way to "fool the network" because it isn't a vote. Nothing is broadcast to the network except complete and valid blocks.