Captcha scams: How to identify and protect yourself

Beware of emerging cyber threat: Fake CAPTCHA scams

We’ve all been there – staring at a CAPTCHA challenge, squinting to determine if that tiny pixelated square contains a traffic light or a fire hydrant. While these verification systems can be frustrating, they serve an important purpose in distinguishing humans from bots. Unfortunately, cybercriminals have found a way to exploit our familiarity with these challenges through sophisticated captcha scams.

According to a recent report by Microsoft Security, captcha scams have become increasingly sophisticated in recent months, with thousands of users falling victim. This growing threat demands our attention and awareness.

What are fake CAPTCHA scams?

A fake captcha may ask you to perform unusual actions like pressing specific key combinations or copying and pasting text – actions legitimate CAPTCHAs never request. These deceptive verification systems are designed to trick users into executing malicious commands that compromise their devices and personal information.

Many users wonder: is CAPTCHA safe to interact with on websites they visit? While legitimate CAPTCHA systems from trusted providers like Google reCAPTCHA are safe, the rise of convincing imitations has made this question more relevant than ever.

How Captcha scams work

• Fake CAPTCHA requests: Users are prompted to verify they are not robots, but instead of a standard CAPTCHA, they encounter steps designed to execute malicious commands.
• Clipboard hijacking: The scam uses JavaScript to copy a command to the user’s clipboard, which is then pasted into the Run dialog box, triggering the download of a malicious file.
• Malware payloads: The downloaded file often contains encoded PowerShell commands that silently retrieve and execute malware.

Understanding how captcha scams work is essential for protecting your personal information online. These attacks typically follow a specific pattern:

1. Initial Contact: You receive an email or encounter a website with a security warning or verification requirement.
2. Fake CAPTCHA requests: Users are prompted to verify they are not robots, but instead of a standard CAPTCHA, they encounter steps designed to execute malicious commands.
3. Clipboard hijacking: The fake CAPTCHA uses JavaScript to secretly copy malicious code to your clipboard.
4. Command execution: You’re instructed to press Windows+R to open the Run dialog and paste the contents (the malicious code).
5. Malware deployment: Once executed, the code downloads and installs malware that can steal passwords financial information, or give attackers remote access to your system.

The latest captcha phishing techniques use JavaScript to hijack your clipboard without your knowledge, making them particularly dangerous. Security researchers have identified a campaign called “Storm-1865” that specifically targets users of popular booking websites with these tactics.

Warning signs of fake CAPTCHA

Learning how to identify fake captcha challenges can protect you from malware and credential theft. Here are key red flags to watch for:

Unusual instructions

Legitimate CAPTCHAs typically ask you to:

• Identify objects in images
• Type text from an image
• Solve simple puzzles or math problems
• Click a checkbox

Be extremely suspicious if a CAPTCHA asks you to:

• Press specific key combinations (like Windows+R)
• Copy and paste text or commands
• Download software to complete verification
• Enter personal information beyond a simple checkbox

Suspicious URLs and Websites

The question “is CAPTCHA safe” has become more relevant as scammers create convincing imitations. Before interacting with any CAPTCHA:

• Check the website URL carefully for misspellings or unusual domains
• Be wary of sites you’ve never visited before

How to protect yourself from CAPTCHA scams

Security experts warn that captcha scams are among the fastest-growing cyber threats in 2025. Here are essential steps to protect yourself:

Only use trusted websites

• Stick to websites you know and trust when completing any verification
• Access websites directly by typing the URL rather than clicking links
• Be especially cautious with financial, shopping, and travel websites

Verify before interacting

• Double-check the URL before interacting with any CAPTCHA
• Look for signs of a legitimate website (professional design, working links, contact information)
• If something seems suspicious, close the page immediately

Technical safeguards

• Keep your operating system and browsers updated
• Use reputable antivirus and anti-malware software
• Consider browser extensions that block malicious scripts
• Enable multi-factor authentication on important accounts

Organisational protection

For businesses, additional measures are crucial:

• Implement employee security awareness training
• Deploy advanced email security solutions

What to do if you encounter a CAPTCHA scam

If you suspect you’ve encountered a fake captcha:

1. Close the page immediately without interacting further
2. Run a malware scan on your device using reputable security software
3. Monitor your accounts for any suspicious activity
4. Report the incident to your IT department or service desk if it occurred on a work device
5. Change passwords for important accounts if you believe you may have been compromised

While legitimate CAPTCHA systems are safe, it’s important to verify you’re on a trusted website before engaging with any verification challenge. Cybercriminals continually evolve their tactics, making ongoing awareness essential. Share on X

Remember: legitimate CAPTCHAs never ask you to run commands, press system key combinations, or paste text into your computer’s Run dialog. When in doubt, close the page and access the website through official channels.