What Is Malvertising?

Malvertising refers to malicious advertising that cybercriminals use to inject malware into users' computers when they visit malicious websites or click on an ad online. Malvertising may also direct users to a corrupted website where their data can be stolen or malware can be downloaded onto their computer.

Malvertisements are spread through the Internet, appearing on both illegitimate and legitimate websites.

In many cases, an advertiser may not be able to tell the malvertisement is malicious, so they run it, thinking it is harmless. After the advertiser agrees to run the ad, it gets sent via a server to otherwise harmless websites. After a user clicks on the malvertisement, code starts running in the background, causing it to potentially download malware onto the user's computer. This is referred to as a drive-by download. These have resulted in so many infections that, according to the New York Times, the U.S. government had to remove malware from the Internet to reduce the chances of Russian attackers using them to breach networks.

In some cases, the user does not even need to click on the malvertisement for the drive-by download to be successful. As long as they load an infected webpage or landing page, the malware can be downloaded. If someone clicks on malware, however, they may get sent to a different webpage designed to exploit vulnerabilities in their browser when it displays ads. This type of exploit is different from an exploit kit, which is a malware hacking toolkit attackers use to try to take advantage of their victims’ systems.

Malvertisements have a few distinct traits that can make them easy to spot if you know what to look for, including:

1. Ads that look sloppy or unprofessional
2. Ads with spelling mistakes
3. Ads that have unrealistic promises, such as amazing cures
4. Ads talking about celebrity scandals
5. Any ad that advertises something that is too good to be true
6. Ads that do not seem to align with your recent search activity

Although somewhat similar, malvertisements and ad malware are distinct. Malvertising in cybersecurity results from criminals using malicious ads within ad networks. The ads then appear on a web page and impact visitors.

Ad malware is different. This type of malware gets installed on a user’s computer and inundates the machine with unwanted advertisements. 

Keep in mind, though, that malvertisements can also be a vehicle for getting malicious adware installed on someone’s computer.

You can prevent malvertising using several different methods, from installing software to adjusting your settings to simply avoiding advertisements altogether.

If you install an ad blocker, ads will not pop up on your screen, including malvertisements. This way, when you go to a webpage with malvertisements on it, you will only see the webpage’s content and not the fake ads hackers have worked into the advertising network.

Your browser has a click-to-play option, so any content that needs a plugin to play is disabled unless you specifically choose to click on it. With click-to-play enabled, you can be protected from malvertisements that automatically run when plugin content loads on a page.

Antivirus software can be a powerful deterrent against malvertisement because it is designed to prevent particular kinds of malware, including malvertising. The key is to keep your antivirus software updated. If a new type of malvertising gets introduced to the internet, you want to ensure your antivirus can identify it and protect your system.

If you see an ad that looks as if someone just haphazardly threw it together, if could be malvertising. Malvertisers may not put the time and effort into designing a polished, professional-looking ad in the same way a professional ad company would.

You should also check for spelling errors. Malvertisement designers who hail from other countries may target people in your language but make obvious errors. If you see spelling errors in an advertisement, do not click on it.

Any ad that contains promises that seem unrealistic may be clickbait tempting you to click on a malvertisement. Do not click on ads like this even out of curiosity. You should also keep in mind that if you do click on one, you may not even notice that malware has been downloaded, so even if nothing happens after you click, your computer can still be compromised.

You can also choose to never click on any ads that show up on your computer. In this way, any malvertisements that require a click to be activated will not be able to penetrate your system. If you are interested in a product or service, you can look up the company in the ad and inquire directly through email or via a phone call. This way, you avoid malvertisements and the various types of malicious code they can introduce to your system.

In some cases, you do not have to click on malvertising for it to impact your device. With a drive-by download, for example, the viewer merely sees an ad on their screen and because they are interacting with the malware’s domain, it gets downloaded onto their device automatically. In many cases, there is no indication—at least at first—that the device has been infected. Soon, however, the user may notice it is slowing down, running too hot, or quitting applications out of the blue.

Does this fit the standard malvertising meaning? Yes, this aligns with the accepted malvertising definition because even though the user does not have to click on the content, the attacker is still using an advertisement to attack their system.

Another way malvertising affects users is through URL malvertising. What is URL malvertising? It happens when your browser gets forcibly redirected to a malicious site. What is a malvertising attack in this context? When you get sent to the fake site, you may try to click on something to navigate away from it, and that clicking action installs malware on your device.

You can use FortiSandbox to trap malware that has penetrated your system, whether it came from a malvertisement or another source. It confines what an application can do and where it can go, trapping it inside a safe, quarantined area. At that point, the rest of your system and network are safe. Cybersecurity administrators can then study the malware or simply discard it. When analyzing the actions of malware, admins can learn its behavior and use this information to bolster threat intelligence to defend against that and similar attacks in the future.

Also, the Fortinet Secure Web Gateway (SWG) can protect your business from malicious traffic. It can identify a threat before it enters the network and then discard relevant data. This is accomplished using secure sockets layer (SSL) inspection, which is able to detect malware even if it is hidden within encrypted data.

Malvertising refers to malicious advertising that is used to inject malware into users' computers when they visit a website or click on an ad on the internet.

Malvertisements are distributed through the internet, appearing on both illegitimate and legitimate websites.

Malvertising comes with considerable risks that can threaten your computer, network, or mobile device including; inoperable computers and networks, hardware failure, and data loss.

Malvertisements have a few distinct traits that can make them easy to spot if you know what to look for, including sloppy or unprofessional-looking ads, spelling mistakes, unrealistic promises, or celebrity scandals. If an offer appears too good to be true, beware.