One of the best ways for a hacker to serve malware on trusted websites is to compromise the ad networks those websites use to show ads. This has happened to many a trusted website, including some major news outlets, and usually spells out disaster for people who visit them if malicious ads are being served up.
While controversial, the best way to prevent this is to use an ad-blocker for your web browser. Ad-blockers do prevent websites from earning revenue by serving up legitimate ads when you visit them, but they also prevent you from being hacked when that website’s ads get compromised by hackers.