What Is Malvertising?

Malvertising is the use of online advertising to deliver malicious content, redirect users to harmful sites, or support fraud and malware distribution. In a typical malvertising campaign, the attacker abuses ad networks, sponsored search results, or display ads to get users to click a fake offer, visit a phishing page, or download a malicious file. Instead of compromising the website itself, the attacker abuses the advertising ecosystem around it.

How malvertising works

Malvertising works because users often trust the context in which they see an ad. If the ad appears in search results, on a known website, or inside a reputable platform, people may assume the link is safe. Attackers use that trust to get traffic into attacker-controlled infrastructure.

There are several common ways this happens.

Fake or malicious ads

An attacker creates an ad that impersonates a real product, service, software vendor, bank, or support brand. The ad may promise:

• A login page
• A software download
• A browser update
• A customer support number
• A discount or urgent offer
• A file conversion or document tool

When clicked, the ad sends the victim to a phishing page, scam site, or malware download.

Abuse of sponsored search results

One of the most common modern forms of malvertising is a malicious sponsored search result. A user searches for a legitimate tool, brand, or service, and the ad at the top of the results looks authentic. But the destination is a lookalike domain controlled by the attacker.

This is especially effective for:

• Remote access tools
• Browser downloads
• Cryptocurrency services
• Business software portals
• Webmail and cloud login pages
• Tax, payroll, or HR platforms

Users often trust the top result and click before checking the URL carefully.

Redirect chains

Some malicious ads do not immediately land the user on the final scam page. Instead, they send the browser through one or more redirects. This can help attackers:

• Filter victims by geography or device
• Avoid detection
• Swap destinations over time
• Deliver different payloads to different targets

A user may think they clicked one ad and end up somewhere entirely different a moment later.

Browser-based exploitation or drive-by behavior

Historically, some malvertising campaigns used ad content to trigger browser-based exploitation, sometimes without requiring a click. In those cases, simply loading the malicious ad was enough to expose the browser to harmful code if the system was vulnerable.

That behavior is less central than straightforward phishing and scam redirects in many environments today, but it remains part of why malvertising is taken seriously.

What attackers want from malvertising

Malvertising is just a delivery mechanism. The actual objective may vary.

Common attacker goals include:

• Stealing usernames and passwords
• Delivering malware or loaders
• Tricking users into calling fake support
• Harvesting payment card information
• Distributing fake software installers
• Capturing cryptocurrency wallet details
• Generating affiliate or fraud revenue
• Directing users into business email compromise or account takeover chains

In other words, the ad is not the end of the attack. It is the first stage.

Why malvertising is effective

Malvertising keeps working because it blends into normal web activity.

It inherits trust from the surrounding platform

Users may be on a legitimate website or search engine when they encounter the ad. That makes the malicious content feel less suspicious than an unsolicited email or text.

Ads are built to drive clicks

Digital ads already use urgency, branding, and calls to action. Attackers simply mimic those patterns. The result can look completely normal to a rushed user.

Users often focus on the brand, not the destination

If the ad says the right company name or shows the right logo, many users click without inspecting the URL. On mobile screens, that problem gets worse.

When you’ll encounter malvertising

Malvertising comes up in several common security scenarios.

During phishing or account takeover investigations

If users report entering credentials into a fake page they reached from a web search, malvertising is often part of the story. The compromise may not have started with email at all.

For related background, see what is phishing.

In help desk and browser support cases

Users may complain that they were redirected to fake antivirus warnings, bogus update prompts, or technical support scams. Those incidents often trace back to ads, pop-ups, or malicious redirect chains.

In software download and installer problems

A common pattern is a user searching for a legitimate application and downloading a trojanized installer from a sponsored result instead of the real vendor site.

If you want to understand the malware delivery angle, read what is a trojan.

In enterprise web filtering and DNS security discussions

Security teams encounter malvertising when tuning browser protections, DNS filtering, secure web gateways, and category-based blocking. Ad-driven threats are part of normal web traffic, so they need practical controls.

How organizations reduce the risk

Most defenses against malvertising are operational rather than exotic.

Useful controls include:

• Training users to be cautious with sponsored results
• Verifying domains before entering credentials
• Using DNS filtering or secure web gateways
• Keeping browsers and plugins patched
• Blocking known malicious domains and redirectors
• Restricting software installation rights
• Using endpoint detection for suspicious downloads and child processes
• Considering ad blocking in higher-risk environments where appropriate

A simple but effective habit is teaching users to navigate directly to known vendor sites for logins and downloads instead of relying on search ads.

For users on personal devices or small-business endpoints, security tools like Malwarebytes can add a useful layer against malicious downloads and browser-based threats. If users frequently land on fake login pages, a password manager such as 1Password can also help by making it easier to use unique credentials and by not autofilling on lookalike domains.

Bottom line

Malvertising is malicious activity delivered through digital ads and sponsored placements. The attack may look like a normal ad experience, but the goal is to push users toward phishing, fraud, or malware. If your users depend on web search and browser-based workflows, malvertising is part of your real-world threat surface.