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5 Signs Your Business Has Been Hacked

By Ezekiel Libara · April 2026 · 6 min read

Most business owners don't find out they've been hacked until weeks — sometimes months — after the breach. By then, the damage is done. Hackers are patient. They get in quietly, move around slowly, and only reveal themselves when it's too late. Here are five warning signs you should never ignore.

1. Your Computer Suddenly Slows Down

If your system starts running unusually slow for no clear reason, don't just blame old hardware. Malware and spyware consume significant CPU and memory resources in the background. Ransomware also performs heavy encryption operations before locking you out. A sudden, unexplained drop in performance is a red flag.

What to do: Open Task Manager (Windows) or Activity Monitor (Mac) and look for unfamiliar processes using a lot of resources. If you see something you don't recognize, disconnect from the internet and call an IT professional.

2. Unusual Account Activity or Locked Out

Are you receiving password reset emails you didn't request? Are colleagues saying they got strange emails from you? Or did you suddenly get locked out of your own accounts? These are classic signs that someone has gained unauthorized access to your credentials. Hackers often change passwords immediately after gaining entry to lock the real owner out.

What to do: Enable multi-factor authentication (MFA) on every account immediately — email, banking, cloud storage, everything. MFA is one of the most effective barriers against unauthorized logins even when your password is compromised.

3. Files Have Been Encrypted or Gone Missing

One day your files open normally. The next, they have strange extensions like .locked, .enc, or .crypted — and they won't open. Or files you know existed are simply gone. This is the signature of a ransomware attack. Hackers encrypt your data and demand payment (usually in cryptocurrency) to give you the key.

What to do: Never pay the ransom — it doesn't guarantee recovery and funds more attacks. Immediately isolate the infected device from your network, restore from your most recent clean backup, and report the incident to the Canadian Centre for Cyber Security (CCCS) at cyber.gc.ca.

4. Unknown Software or Browser Extensions Installed

Have you noticed new programs in your apps list that you didn't install? A new toolbar in your browser? A homepage that changed without your permission? These are signs of unwanted software — often installed through phishing emails, malicious downloads, or drive-by attacks when visiting compromised websites.

What to do: Audit your installed programs and browser extensions regularly. Remove anything unfamiliar. Run a full malware scan using a reputable tool like Malwarebytes. Update all software and browsers immediately.

5. Unexplained Network Traffic or Data Usage Spikes

If your internet bill is suddenly higher, or your router logs show heavy data transfers happening at 3am when no one is in the office, something is communicating without your knowledge. Hackers often use compromised machines as part of botnets to send spam, mine cryptocurrency, or exfiltrate stolen data to external servers.

What to do: Log into your router and review connected devices and traffic logs. Disconnect any device you don't recognize. Contact your ISP for a detailed usage report. A managed firewall solution can help detect and block suspicious outbound traffic automatically.

What Should You Do If You Suspect a Breach?

Disconnect the affected machine from the internet immediately
Do NOT turn it off — preserve evidence for forensic analysis
Change all passwords from a clean, unaffected device
Notify affected clients or partners as required by Canadian privacy law (PIPEDA)
Contact a cybersecurity professional for incident response

Don't wait until a breach happens to start thinking about security. Prevention is always cheaper than recovery. If you'd like a security assessment for your business, contact EALTech today.