Scammers always use phishing techniques to create fake websites that contain malware. Quite a lot of events and casualties especially those who like free coins and follow the airdrop are not obvious because many tasks must be completed including one visiting their website. How to check, I think there are many references that can be done, for example, check for security signs such as the "https" protocol and the padlock icon, and if it looks genuine and doubtful, make it a habit to look for reviews or additional information to strengthen the important thing, don't just click.