What is the main goal of an attacker setting up an evil twin attack?

The primary goal of an attacker setting up an evil twin attack is to steal user network credentials. In this type of attack, the malicious entity creates a rogue access point that mimics a legitimate Wi-Fi network. When users connect to this fake network, believing it to be safe, the attacker can intercept sensitive data, including usernames, passwords, and other login credentials. This is particularly dangerous because users often remain unaware that they are connected to a malicious network.

In contrast, the other options underscore different aspects that do not align with the main intent of an evil twin attack. Taking over legitimate network infrastructure points more towards a different kind of attack involving compromising actual network devices rather than tricking users into giving away information. Enhancing network performance is not a goal of malicious attacks at all; it suggests improving service, which runs contrary to the nature of an evil twin setup. Snoop on connections with web servers, while partially related, does not capture the essence of the evil twin attack's primary motive, which centers around deceiving users into divulging their credentials.