At their best, online advertisements help connect consumers with products and services that match their needs. At their worst, they can become a gateway for malicious software that infects users’ devices.
A recent report found that in 2025 malicious advertising, often called “malvertising,” overtook email scams and direct hacking attempts as the leading method used to distribute malware across the internet.
Cybercriminals use malware to infiltrate computers and networks, aiming to steal sensitive data, demand ransom payments, or disrupt systems. In many cases, the victim does not even need to click on the advertisement—simply loading the compromised ad on a webpage can trigger the infection.
As digital advertising continues to dominate the online economy, the same systems designed to target audiences and deliver ads at scale are increasingly being exploited by attackers to spread harmful software to millions of users.