Earlier last year, several U.S. law firms were hit with a string of cyberattacks – and they never saw it coming. Staff at these firms were simply doing routine research online when they clicked on links for legal templates or court filing resources. The websites looked normal.
But instead of useful documents, they got malware. Malware that was planted through malicious ads. In some cases, this led to unauthorized access to confidential files, stalled operations, and serious fallout with clients.
The threat didn’t come through an email or an obviously sketchy download.
It came from a Google ad.
This is a perfect example of malvertising in action. If you’re running a small or mid-sized law firm, it’s something you need to be aware of.
So, What Exactly Is Malvertising?
Malvertising (short for malicious advertising) is when attackers sneak malware into online ads. These ads can show up on search engines, social media, or even trusted news sites.
You might think, “Well, I don’t click on anything shady.” But that’s the thing; these ads often look completely legit. Some don’t even require a click to do damage.
A well-placed malicious ad can install malware the moment you load a webpage, or redirect you to a fake version of a trusted site where attackers can collect your login credentials or trick you into installing software laced with spyware.
Why Law Firms Are on the Hit List
Your firm holds the exact kind of data cybercriminals want: legal documents, financial details, and sensitive client information. They know many smaller firms don’t have full-time IT teams or enterprise-grade security tools. That makes your firm a tempting target.
And unlike phishing emails or ransomware that raise red flags, malvertising operates quietly. A staff member can be infected just by doing a Google search and clicking what seems like a completely harmless ad.
The aftermath? Potential data breaches, lost client trust, regulatory issues, and a mountain of downtime.
Common Types of Malvertising Attacks
Here are a few ways attackers use malvertising to get in:
Fake Software Ads
These look like ads for tools you already use. Think Adobe, Zoom, or legal form builders. You click to download, and instead you install malware.
Drive-By Downloads
Just visiting a site with a bad ad can be enough to trigger an automatic malware download, no clicks needed.
Redirect Traps
You think you’re going to a real website, but the ad sends you to a lookalike version built to steal your credentials or infect your system.
SEO Poisoning
Cybercriminals sometimes get their malicious ads approved through real ad networks, only to switch out the content later, once the ads are live.
How to Protect Your Firm
You don’t need a huge IT team to reduce your risk. Here are practical steps you can take:
Use a Trusted Ad Blocker
This one’s easy. Ad blockers help cut off these threats before they ever show up in your browser. Admittedly, this is getting trickier with recent Chromium changes, so you may want to look at a network wide solution, such as filtering on your firewall.
Train Your Team
Make sure everyone, from attorneys to assistants, knows not to blindly trust online ads or downloads, even if they look professional. A little awareness goes a long way.
Install Reliable Security Software
Use well-reviewed antivirus and anti-malware tools. Many come with real-time protection to block threats as they happen.
Keep Software Updated
Attackers love old software with known security holes. Patching your systems regularly is one of the most effective defenses.
Limit Installation Privileges
Restrict who can install apps or change system settings on firm devices. If malware can’t run, it can’t spread.
Monitor Network Activity
Pay attention to strange spikes in traffic or outbound connections to unknown servers. These are often early signs of infection.
The Final Verdict
Malvertising is sneaky, and it’s on the rise, especially against law firms. But you don’t need to be a cybersecurity expert to stay safe. The key is knowing this threat exists, staying cautious about what you click, and putting basic protections in place.
If your firm hasn’t looked into this yet, now’s the time. A single click shouldn’t cost you your clients, your credibility, or your business.
Next step?
Start by scheduling a quick cybersecurity refresh with your team. Simple actions, serious impact. Need some help? Get in touch, that’s what we do.