What is Malvertising And How Can Publishers Protect Themselves?

Imagine visiting your favorite website, only to be bombarded by unexpected pop-ups or redirected to a suspicious site. You’d leave immediately, right? That’s the power—and the problem—of malvertising. It’s a deceptive form of online advertising that not only frustrates users but can also damage publishers’ reputations, revenue, and trustworthiness.

For publishers, malvertising is more than just a nuisance—it’s a growing threat. Understanding what it is, how it works, and how to protect your site is crucial in the programmatic advertising world. In this post, we’ll break down everything you need to know about malvertising, from real-world examples to practical solutions, and show how Snigel is helping publishers stay safe.

What Is Malvertising?

Malvertising, short for “malicious advertising,” is a sneaky tactic used by cybercriminals to embed harmful code within legitimate-looking ads. These ads appear on trustworthy websites and can cause damage without users even clicking on them.

What makes malvertising so dangerous is its stealth. By the time a malicious ad is displayed on a publisher’s site, it has often bypassed multiple layers of ad vetting. Once live, these ads can execute harmful actions like forcing users to unwanted sites, stealing personal data, or installing malware.

Whether you’re a large publisher or just starting out, malvertising poses a real threat. If users lose trust in your site, they’re likely to stay away—and worse, they may block your ads altogether.

Malvertising Examples And How They Affect Users

Malvertising can take many forms, but the most common examples include:

• Forced Redirects Imagine clicking on a news article, only to be automatically redirected to a suspicious website offering a fake prize. These redirects happen without user interaction, hijacking the browsing experience and often leading to phishing sites or malware downloads.
• Malicious Ads Sometimes, an ad that looks completely harmless can carry hidden malicious code. When displayed, these ads might silently install harmful software on a user’s device or steal sensitive information.
• Ransomware Campaigns In extreme cases, malvertising can deliver ransomware—a type of malware that locks users out of their devices or data until a ransom is paid. These attacks can target unsuspecting users through seemingly ordinary ads on reputable sites.
• Fake Software Updates Malvertising campaigns often disguise malware as a legitimate software update. For instance, users might see an ad prompting them to “update their browser” or install a “security patch,” only to end up downloading malicious software instead.

These examples illustrate the deceptive nature of malvertising and why publishers need to protect their sites and users from these attacks.

How Does Malvertising Work?

At first glance, malvertising might seem like something that only happens on shady websites, but that couldn’t be further from the truth. Cybercriminals have become experts at sneaking malicious ads into reputable ad networks, making it possible for them to appear on high-traffic, trustworthy sites.

Here’s how it typically happens:

1. Creating the ad – The bad actor designs an ad that looks harmless but hides malicious code.
2. Submitting it to ad networks – These ads are submitted to programmatic ad exchanges, blending in with legitimate ads.
3. Reaching the user – Once served on a publisher’s site, the ad can:
   • Redirect users to phishing websites.
   • Automatically download malware onto devices.
   • Use exploit kits to find vulnerabilities in a user’s browser or operating system.

This process is designed to be invisible, making it difficult for publishers to detect the threat until the damage is done. For publishers, the fallout is significant: frustrated users, damaged reputations, and a potential dip in ad revenue.

How Malware is Delivered Through Ads

Cybercriminals use various methods to inject malicious code into ads, often exploiting vulnerabilities in the programmatic ad ecosystem. Here are some common delivery methods:

• Malware in Ad Calls When an ad is served on a website, third-party bidders vie for that ad space via an ad exchange. If a bad actor compromises any part of this process, malicious code can be embedded in the ad payload, impacting users the moment the ad is displayed.
• Post-Click Malware Clicking on an ad often initiates a chain of redirects before reaching the final landing page. If an attacker has compromised any of these redirects, malware can be inserted along the way, targeting users who interact with the ad.
• Malware in Ad Creatives Malicious code can be embedded directly into banners, text ads, or even carousel formats. Flash-based ads were particularly vulnerable in the past, though its discontinuation in 2020 has reduced this risk.
• Malware in Video Ads Video ads present a unique challenge, as they can hide malicious code in unexpected places. For instance, users may be exposed to malware embedded in a pre-roll image or redirected to harmful sites after watching the video.
• Malware in Tracking Pixels Tracking pixels are small, invisible components used to monitor user behavior on a site. If a pixel is compromised, it can deliver malicious code to users simply by loading on the page—no clicks required.
• Drive-by Downloads Some malvertising campaigns employ drive-by downloads, where harmful software is installed on a user’s device simply by loading the page with the malicious ad—no clicks required.

Each of these methods underscores the complexity of malvertising and why publishers must remain vigilant. By understanding how malware is delivered, publishers can take proactive steps to secure their sites.

Why is Malvertising a Threat to Publishers?

For publishers, malvertising isn’t just a threat to users—it’s a direct attack on the trust and reputation you’ve worked so hard to build. When malicious ads make their way onto your site, they impact far more than just the user experience.

Here are some of the biggest risks malvertising poses to publishers:

• Loss of User Trust: Imagine a loyal visitor encountering a malicious ad on your site. They may blame you for the inconvenience or digital security risks, even though you didn’t place the ad. If users start to feel unsafe on your site, they may leave for good.
• Revenue Loss: Malvertising is one of the main drivers of ad blocker adoption. When users install ad blockers to avoid being exposed to malicious ads, your ad impressions—and revenue—take a hit.
• Reputation Damage: It only takes one incident to harm your brand. Whether it’s negative word-of-mouth or public backlash, being associated with malvertising can tarnish your reputation as a reliable publisher.
• Increased Costs: Dealing with malvertising requires time, effort, and resources. From identifying the source of malicious ads to implementing solutions, publishers often find themselves bearing the brunt of the financial impact.

Malvertising doesn’t just target users—it affects your bottom line, your brand, and your future growth. That’s why it’s essential to have robust safeguards in place to minimize these risks.

Ad Fraud vs. Malvertising

While ad fraud primarily focuses on generating illegitimate revenue by tricking advertisers, malvertising targets users and publishers with harmful intent. Both are costly and damaging in their own ways, but understanding these differences is key to tackling them effectively.

Here’s a side-by-side comparison to clarify how ad fraud and malvertising differ:

	Ad Fraud	Malvertising
Objective	Generate illegitimate revenue through fake clicks, impressions, or bot traffic.	Harm users or publishers by delivering malware, stealing data, or disrupting user experience.
Impact on Users	Rarely noticeable; primarily operates in the background.	Directly impacts users with redirects, malicious downloads, or intrusive ads.
Impact on Publishers	Can damage credibility with advertisers if the site is associated with fake traffic.	Damages trust and reputation with users, leading to potential revenue loss.
Detection	Identified through performance discrepancies, like unusual click patterns.	Evident when users report suspicious ads, redirects, or malware issues.

By addressing these challenges with tailored strategies, you can safeguard your ad revenue, user trust, and overall site reputation.

Adware vs. Malvertising

Adware and malvertising are often mistaken for one another because both involve ads and can harm users. However, while adware is typically focused on delivering intrusive ads and can sometimes be tolerated as part of "free" software, malvertising is far more dangerous. It exploits the trust between users and publishers, using legitimate ad networks to deliver harmful code.

	Adware	Malvertising
Objective	Display excessive or intrusive ads, often to generate revenue.	Deliver malicious code through legitimate-looking ads.
Delivery Method	Installed via bundled software, downloads, or phishing attempts.	Injected into programmatic ad systems and served on websites.
Impact on Users	Annoying pop-ups, browser redirects, or tracking of user behavior.	Direct threats like malware downloads, forced redirects, or phishing.
Impact on Devices	Slows down devices and compromises user experience.	Can install ransomware, steal sensitive data, or damage systems.
Malicious Intent	May not always be malicious but often invasive and privacy-infringing.	Always malicious, with the intent to harm users or exploit systems.

 

How Can Publishers Protect Themselves from Malvertising?

Malvertising may be a pervasive issue, but publishers are not powerless. With the right strategies, tools, and partnerships, you can significantly reduce the risk of malicious ads harming your site and users.

Here are some proactive measures publishers can take:

• Partner with Trusted Ad Tech Providers Choose ad tech companies that prioritize security and invest in advanced anti-malvertising solutions. Look for partners who actively monitor ad quality, provide real-time blocking of malicious ads, and are transparent about their processes.
• Implement Technical Safeguards Utilize tools like malware scanners, ad verification solutions, and firewalls to detect and block malicious activity before it reaches users. Regularly updating your site’s software, plugins, and systems can also close vulnerabilities that malvertisers might exploit.
• Adopt a Layered Security Approach Combine multiple layers of protection, including third-party tools and internal vigilance, to catch online threats at different stages of the ad serving process. This is especially important for programmatic advertising, where ads pass through numerous intermediaries.
• Monitor and Audit Ads Regularly Keep an eye on the ads displayed on your site. Conduct periodic audits to ensure all ads align with your quality standards, and quickly address any reports of suspicious activity from users or ad ops teams.
• Strength in Numbers Awareness is a powerful tool. Train your team to recognize signs of malvertising and respond swiftly to any incidents. Encourage users to report suspicious ads and have a clear process in place for handling these reports efficiently.

Proactively protecting your site from malvertising requires effort, but the payoff is immense—user trust, brand reputation, and stable revenue streams.

Anti-Malvertising Tools and Practices

While working with a trusted ad tech partner is essential, you can also explore independent tools and practices to strengthen your defenses against malvertising. These solutions help identify and mitigate threats, ensuring web safety.

1. Ad Verification Tools

Ad verification platforms like GeoEdge or The Media Trust specialize in scanning ad content for malicious activity. These tools monitor ads in real-time, identify malicious behavior, and block harmful ads before they can impact users.

2. Malware Scanners

Software like Sucuri or Malwarebytes can be used to scan your website for malicious code or vulnerabilities. Regularly running these tools can help you catch threats early and prevent them from spreading.

3. Content Security Policies (CSPs)

Implementing CSPs allows publishers to control which sources can execute scripts or load content on their website. This minimizes the risk of malicious code executing through compromised ads.

4. Web Application Firewalls (WAFs)

A WAF acts as a shield between your website and incoming traffic. It can block suspicious activity, such as attempts to inject malicious ads or exploits of a sites vulnerabilities. Popular WAF providers include Cloudflare and Akamai.

5. Regular Ad Quality Audits

Performing frequent audits of the ads displayed on your site helps you spot and address any potential issues. Tools like AdSecure offer automated solutions for auditing ad creatives and detecting non-compliant or malicious content.

6. Stay Informed

The tactics used by malvertisers evolve constantly. Stay up to date with the latest industry trends, threats, and solutions by following trusted sources, such as IAB Tech Lab or cybersecurity blogs.

7. Threat Intelligence Tools

Publishers can benefit from integrating threat intelligence platforms into their security strategy. These tools analyze patterns in malicious activities to predict and prevent future attacks. By staying ahead of the curve, threat intelligence can help publishers minimize potential risks.

By integrating these tools and practices into your site’s security strategy, you can create a robust defense system that complements your ad tech partner’s efforts.

 

Snigel’s Approach to Tackling Malvertising

At Snigel, we understand the serious impact malvertising can have on publishers. From frustrating users to harming your site’s reputation, the risks are too significant to ignore. That’s why we’ve made it a priority to safeguard our publishers with a proactive and comprehensive approach to tackling malvertising.

Snigel partners with industry-leading anti-malvertising solutions to stay ahead of emerging threats. These tools are continuously updated to detect and block malicious ads in real time, ensuring your site and users remain protected. At present, our partner's solution has over 80 malvertising techniques mapped, providing unparalleled coverage.

Our Ad Operations specialists also play a key role in keeping your site safe. They actively monitor ad inventory to catch issues early and take swift action to block any malicious ads. If an issue is reported, we move quickly to eliminate the threat across our network and investigate further to prevent similar incidents.

We also believe in working closely with publishers. Often, you’re the first to spot malvertising, and that’s why we make it easy to report issues. If you notice anything suspicious, simply share:

• A screenshot of the malicious ad.
• The URL of the page where it appeared.
• The destination URL of the ad.

This collaboration ensures we can act fast, protect your site, and minimize disruption to your users.

Finally, we are committed to continuous improvement. The landscape of malvertising is always evolving, and so are we. We regularly evaluate and test new solutions to ensure our strategy remains effective. While no system is foolproof, we’re dedicated to minimizing the impact of malvertising as much as possible.

By working together, we can create a safer and more trustworthy ad experience for your users.

Conclusion

Malvertising might feel like a daunting challenge, but it’s one you don’t have to face alone. By taking proactive steps—like partnering with trusted ad tech providers, using advanced tools, and staying vigilant—you can protect your site, your users, and your reputation.

At Snigel, we’ve made it our mission to help publishers tackle malvertising head-on. With industry-leading tools, dedicated support, and a focus on collaboration, we’re here to ensure your site stays safe and your revenue keeps growing.

Want to learn more about how Snigel can help? Reach out today, and let’s work together to build a safer and stronger future for your site.