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The FBI Denver Field Office has issued a warning about a rising scam involving fake online document conversion tools that implant malware into files, compromising corporate networks. Cybercriminals are exploiting free document converter or downloader websites, which appear legitimate but deliver malicious payloads. These sites often claim to convert file formats (e.g., .doc to .pdf) or merge files (e.g., multiple .jpg into one .pdf). While they perform the advertised task, the output files contain hidden malware, granting attackers access to victims’ systems.
You Should Know:
1. How the Attack Works
- Attackers lure users with free online tools.
- The converted/downloaded file contains embedded malware (e.g., ransomware, spyware).
- Malware executes upon opening the file, compromising the system.
2. Detection & Prevention
- Verify Websites: Use only trusted, well-known conversion tools (e.g., Adobe, Smallpdf).
- Scan Files: Before opening, scan with antivirus or tools like VirusTotal (
curl -X POST --url 'https://www.virustotal.com/vtapi/v2/file/scan' --form 'apikey=YOUR_API_KEY' --form '[email protected]'). - Sandboxing: Test suspicious files in a sandboxed environment (e.g.,
cuckoo submit malicious.pdf).
3. Mitigation Commands (Linux/Windows)
- Linux:
- Check file hashes: `sha256sum suspicious_file.pdf`
- Isolate malicious processes: `kill -9 $(pgrep -f “malicious_process”)`
- Monitor network traffic: `tcpdump -i eth0 -w traffic.pcap`
- Windows:
- Analyze file metadata: `powershell Get-FileHash -Algorithm SHA256 suspicious_file.pdf`
- Remove persistence: `reg delete “HKCU\Software\Microsoft\Windows\CurrentVersion\Run” /v “MalwareEntry” /f`
4. Reporting the Scam
- Report to the FBI via IC3.gov.
- Share IoCs (Indicators of Compromise) with your security team.
What Undercode Say
This attack exploits user trust in free tools, emphasizing the need for strict internet access controls in corporate environments. Always enforce:
– Endpoint Protection: Tools like CrowdStrike or Windows Defender (Get-MpThreatDetection).
– Network Segmentation: Limit lateral movement with firewall rules (iptables -A INPUT -s MALICIOUS_IP -j DROP).
– User Training: Regular phishing simulations (gophish).
Expected Output:
- A secure workflow for file conversions (e.g., offline tools like LibreOffice).
- Increased awareness of FBI alerts (FBI Notification).
- Proactive monitoring with SIEM tools (
sudo apt install osquery).
Stay vigilant—malware hides in plain sight.
References:
References:
Reported By: Charlescrampton Still – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
