file security9 min
Dangerous File Extensions That Carry Malware
Learn which file extensions can carry malware, how attackers disguise executables, scripts, macros and double extensions, and how to check a file safely.
Read more→File Security Analyzer
Analyze files for security risks 100% client-side. Detect malware indicators, extension mismatches, macros, and more. Files never leave your browser.
Processing: local in your browser
Free Online File Security Analyzer
Analyze files for security risks 100% client-side. Detect malware indicators, extension mismatches, suspicious macros, hidden metadata, and more. Files never leave your browser, unlike most online scanners that require uploading your files to their servers.
What Threats We Detect
Our analyzer performs multiple security checks: it compares magic bytes with the file extension to detect fake extensions (e.g., an .exe disguised as a .pdf), looks for known malware signatures in the file content, identifies macros in Microsoft Office documents that could execute malicious code, and analyzes metadata to detect suspicious information or traces of attack tools.
Why File Security Matters
Malicious file attachments are one of the most common attack vectors. Office documents with macros, PDFs with embedded JavaScript, and files with fake extensions represent real threats. Checking files before opening them is an essential security practice, especially for files received via email or downloaded from unverified sources.
100% Local & Private Analysis
Unlike services like VirusTotal that require uploading your files, our analyzer runs entirely in your browser. This ensures that confidential documents, contracts, medical records, or other sensitive information are never transmitted to third parties.
Frequently Asked Questions
- How does the file security analyzer work?
- The analyzer examines magic bytes, verifies file extensions, checks for VBA macros and embedded scripts, and computes a SHA-256 hash. Everything is processed in your browser.
- Are my files uploaded to any server?
- No. All analysis is performed 100% in your browser. Files never leave your device.
- What does the tool detect?
- It detects executable files, extension mismatches, suspicious double extensions, VBA macros in Office documents, and embedded JavaScript in PDFs.
Protect Your Device
Our scanner inspects a file in your browser; it does not run resident protection. We picked three engines known for real-time, on-device scanning to cover everything you open after the check.
Top pick
Surfshark Antivirus - Lightweight Protection
Best for: real-time antivirus protection with minimal system impact
Real-time antivirus protection with minimal system impact. Scans files, blocks malware, and protects your webcam.
Get Surfshark Antivirus→Best value
Bitdefender - Total Security
Best for: award-winning antivirus with real-time file scanning
Award-winning antivirus with real-time file scanning. Protects against malware, ransomware, and phishing.
Get Bitdefender→Strong alternative
Malwarebytes - Advanced Threat Protection
Best for: real-time protection against malware, ransomware, and zero-day threats
Real-time protection against malware, ransomware, and zero-day threats. Free scan available.
Try Malwarebytes→We may earn a commission through affiliate links at no extra cost to you.
Recommendations are chosen for fit with the use case; not every recommendation depends on an affiliate relationship.
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How to Check If a File Is Safe to Open
Practical steps to judge whether a downloaded file is safe: check extensions, type mismatches, macros, PDF scripts and hashes before you click.
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