He malvertising It is not new, it has been known since 2008, but it has only been in recent years when it has experienced a strong growth which, according to the latest threat report from the cybersecurity company Digital Gen corresponding to the third quarter of this year, has become the second most used way to distribute malware on devices. The name comes from the contraction between the words malware and advertisingadvertising, and under this name are included various forms of manipulate advertisements that appear on web pages to infect computers with hardly any interaction from the user. Just click on an ad And sometimes, that action isn’t even necessary for them to end up obtaining your personal data, banking data or any other information you have on a device.
What malvertising does is inject malicious code into ads distributed by advertising networksObviously, platforms like Google Ads or others that serve ads have their security mechanisms, but cybercriminals sometimes manage to bypass them. And for that reason, you can find yourself on a website you visit every day with an ad that is either malware or not malware, but misleading, and redirects you to a fake page, which is the other predominant form of malvertising.
For example, last June the case of a malvertising advertisement on the Google platform became known, which, with the hook of Google Authenticatorredirected to a fraudulent web page where the victim downloaded and installed malware instead of the authentication app. In other words, a case of phishing through malvertising.
We leave the misleading ads and return to those containing malicious code. Once the user clicks on such an ad, the malicious code is installed on the computer. This is usually a small piece of code that allows a command and control server to connect to the device and scan it to determine the most effective malware for your case and send it to you. Once installed, the information that the victim stores in their browser and on their computer can be stolen: personal data, financial data, documents, etc. In some cases, it is not even necessary to click on the ad to trigger the malicious activity: just load the web page that hosts the ad.
How to protect yourself from malvertising
Beyond the usual recommendations of keeping all software updated, including browser extensions, there are two methods that prevent this activity.
The first is the most obvious: block ads. It can be done with browser add-ons like Ublock either Adblockor using one that blocks them natively, without having to do anything, as in the case of Brave.It’s something that even the FBI recommends.
The second is Disable JavaScript in the browsersomething that can be done from the settings in the section Setting up sitesInfected ads require JavaScript to run the code, but this can also disable the functionality of other elements of the web page being visited, making it impractical.