Malvertising: An insidious attack through advertising

Imagine you are searching for a new browser to download, and you notice a sponsored link at the top of the search results. The ad looks legitimate, and upon clicking it, you are redirected to a site that resembles the original. You download the browser, install it, and happily use it, but in reality, it was designed to run malware in the background.

This deceptive practice where attackers embed malicious code within online advertisements is malvertising, short for malicious advertisement. These ads are distributed through legitimate advertising networks, making it difficult to detect. When a user interacts with these ads, they execute harmful actions without the user's knowledge, such as redirecting to a malicious website or silently downloading malware onto the device.

With the advent of digital marketing, ad bidding became competitive, as advertisers bid for ad placements in real time. This method of real-time bidding often requires minimal verification, which enables attackers to impersonate legitimate advertisers and enter reputable ad networks. To ensure that the malicious ads are prominently displayed, attackers often outbid the legitimate advertisers. Also, attackers hide and encrypt their malicious ads behind several web links that redirect the user from one site to another before landing on the dangerous page, thus making it harder for the security tools to detect and block it.

Apart from this, AI has aggravated the situation. AI generates highly realistic images, videos, and websites that make the malicious ad look legitimate. Also, AI lets attackers create and modify many different versions of the ads, increasing the probability that malicious ads slip past the security tools. It also helps attackers analyze how a system would detect malicious ads, allowing them to adjust the ad to evade detection.

Malvertising has become a powerful delivery method for a wide range of cyberattacks. Its ability to reach a wide audience with minimal intervention makes it an effective initial attack vector.

An effective mitigation strategy to combat malvertising is to implement browser security tools that could detect and block the malicious ads. Additionally, implement the download filter within the browser security, as it could control and monitor the download and block any unauthorized or suspicious files from being executed.

Check out Browser Security Plus to explore these features to combat malvertising. Start your 30-day free trial of ManageEngine Browser Security Plus.

Meet the author

Sneha P

Technical writer at ManageEngine, passionate about raising awareness of emerging cyber threats. She specializes in translating complex cybersecurity topics into clear, accessible content and aims to make security knowledge practical, actionable, and understandable for a wide audience.