What is Malvertising?
Malvertising is the use of online advertising to spread malicious software, or malware. Malvertising campaigns can use legitimate online display advertising networks and target unsuspecting web users with malicious ads. Once clicked, the malicious ad redirects the user to a website hosting malicious content, such as malware or ransomware, that may be unknowingly downloaded to the user’s device.
How Does it Work?
Malvertising campaigns typically start with the malicious actor buying a legitimate ad space from a legitimate advertising network. They then use a combination of creative and technical means to spread malicious ads. Creatively, malicious ads may appear to be harmless by blending in with the other ads on the page. They may also contain messages that entice the user to click, such as “Download Now” or “Free Trial.” Technically, malicious ads may use code to redirect the user to malicious websites. This code may be hidden in an image, or in the ad’s HTML or JavaScript code.
Examples of Malvertising
Malvertising campaigns have been used to spread malware and ransomware across the internet. In 2016, a malvertising campaign infected over 1 million users with the ransomware Locky. In 2017, a malicious actor was able to exploit Google’s DoubleClick ad platform to spread malicious ads to over 4 million users.
Preventing Malvertising
The best way to protect yourself from malvertising is to be aware of the risks and take steps to protect yourself. Here are some tips:
- Install an ad-blocker on your web browser.
- Make sure your computer and all its software are up to date.
- Be wary of clicking on ads, even if they appear to be from a legitimate source.
- Be aware of phishing emails – if an email looks suspicious, don’t click on any links.
- Keep your anti-virus and anti-malware software up to date.
Malvertising is an ever-evolving threat, but with vigilance and the right precautions, you can protect yourself from malicious actors and their malicious ads.
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