Email security tools have come a long way in protecting businesses from phishing scams and malware attacks. They scan attachments, block known threats, and even analyze suspicious files in isolated environments before they ever reach your inbox. But cybercriminals are always looking for new ways to outsmart these defenses—and lately, they’ve found a clever trick that’s catching law firms off guard.
The latest scam? Intentionally corrupted Microsoft Word documents designed to bypass security scans and lure unsuspecting users into a phishing trap. Here’s how it works, why it’s effective, and—most importantly—what your firm can do to stay protected.
How Cybercriminals Use Corrupted Files to Bypass Security
Most law firms rely on email security tools that scan attachments for known threats. If a Word document contains malware, a security filter will usually flag it, quarantine it, or block it altogether.
But here’s the catch: when a file is deliberately corrupted, security scanners often can’t read it properly. Instead of detecting anything malicious, they dismiss it as a broken or unreadable file and let it through.
When the recipient (a law firm employee, paralegal, or even an attorney) opens the document, Microsoft Word automatically prompts them to “recover” the file—a normal function designed to fix damaged documents. But in this case, the “recovered” file contains hidden malware or a phishing link that tricks the user into entering sensitive credentials, potentially exposing client data, financial information, or even entire case files to cybercriminals.
Why This Tactic Works
This phishing method is effective because it takes advantage of both security tools and human habits:
- Security tools can’t analyze what they can’t read. Corrupted files don’t trigger traditional malware detection because their contents are unreadable—until they’re “fixed.”
- People trust Microsoft’s built-in repair tool. When a law firm employee sees the prompt to recover the document, it looks like a standard system message. Most people wouldn’t think twice about clicking “Yes.”
- Phishing links replace traditional malware. Since many security tools are designed to detect malicious code rather than simple hyperlinks, a recovered document containing a link to a fake login page often goes undetected.
Essentially, cybercriminals outsource the final step of their attack to you—all they need is for someone at your firm to unknowingly complete the process.
How Your Law Firm Can Stay Secure Against Phishing Emails
Even with strong security tools in place, this kind of phishing attack can slip through. The good news? There are proactive steps your firm can take to minimize the risk:
1. Be Wary of Unexpected Attachments
If you receive an email with a Word document attachment—especially from an unknown sender—pause before opening it. Does it make sense that this person is sending you a file? If not, confirm with the sender by phone or a separate email before opening anything.
2. Avoid Recovering Corrupted Files
If you open a Word document and see a prompt asking if you’d like to recover it, stop and think. If the document was sent via email and isn’t something you were expecting, do not click “Yes”—report it to your IT team instead.
3. Implement Multi-Layered Email Security
Your firm’s email security should include:
- Advanced attachment scanning that can analyze a file’s behavior, not just its content.
- URL protection that checks links in email attachments, even after they’re opened.
- User training to help employees recognize phishing attempts and suspicious attachments.
4. Encourage a “Zero-Trust” Approach
Train your team to assume that every unexpected attachment could be malicious until proven otherwise. Simple habits, like verifying documents before opening them and questioning suspicious emails, can go a long way in preventing attacks.
5. Keep Software & Security Systems Updated
Ensure that Microsoft Office, email security filters, and endpoint protection software are up to date. Cybercriminals exploit outdated systems, so regular updates are crucial.
Cybersecurity Is Best Handled in Layers
No single security tool can catch every threat—especially when cybercriminals develop new ways to bypass detection. That’s why law firms need a layered approach to cybersecurity:
- Technology: Strong email filtering, attachment scanning, and anti-phishing tools.
- Policies: Strict rules for handling email attachments and verifying unexpected files.
- Training: Equipping employees with the knowledge to recognize and avoid scams.
By combining these strategies, your firm can stay ahead of evolving threats and protect the sensitive legal and financial information that clients entrust to you.
Phishing scams will keep evolving—but with the right security measures and a cautious approach, your firm can avoid becoming the next target.