Trust Bytes, Not Extensions
Universal file viewer and forensic inspector running entirely in your browser. Decode magic numbers, strip malicious payloads, and analyze true file structure.
$ file malicious.pdf.exe
malicious.pdf.exe: PE32 executable (GUI) Intel 80386
$ uviewfile --analyze
[+] Magic number: 4D 5A (MZ)
[!] Extension spoofing detected
[!] RTLO character detected in filename
[+] Entropy: 7.82 (High - likely packed/encrypted)The OS is Lying to You
Modern operating systems hide file extensions by default and rely on superficial metadata to determine execution context. This single design decision is responsible for billions in ransomware damage.
Zero-Trust Architecture
Local Execution
WebAssembly and modern File System Access APIs mean your files never leave your device. Analysis happens on your CPU, cutting upload latency to zero.
Raw Byte Access
OS-level viewers lie to you. We display the exact byte sequence, highlighting standard headers, anomalies, and trailing data commonly used for payloads.
Format Agnostic
From obscure 90s archive formats to modern corrupted media files, we parse the structure based on signatures, not unreliable metadata.
Beyond Simple Viewing
Standard file viewers attempt to render the file, exposing your system to parsing vulnerabilities (like zero-click exploits in image libraries). uViewFile isolates and analyzes.
- Magic Number Validation: Checks the first 32 bytes against our database of 14,000+ signatures to verify true file type.
- Entropy Analysis: Calculates Shannon entropy to detect packed, encrypted, or compressed payloads hiding inside innocuous files.
- Metadata Extraction: Safely strips EXIF, ID3, and XMP data without executing embedded scripts.
- String Extraction: Dumps printable ASCII and Unicode strings for rapid malware triage.
Why not just double-click?
In 2023, 41% of malware was delivered via "safe" file formats like PDF or Office documents. The host application's parser is the attack vector.
Read the security guideInstant Triage. Zero Install.
Drop an unknown binary directly into the browser to calculate its hash, read its headers, and measure entropy before committing to a sandbox analysis.
Launch Hex ViewerCore Engine Features
Streaming Parser
Handles multi-gigabyte ISOs and database dumps without crashing the browser tab by utilizing the Web Streams API and virtualization.
Polyglot Detection
Identifies files that are simultaneously valid in multiple formats (e.g., a GIF that is also a valid Java ARchive) to prevent evasion.
RTLO Unmasking
Detects and visually flags Unicode Right-to-Left Override characters used to spoof file extensions in phishing campaigns.
YARA Rule Export
Quickly select byte sequences from the hex viewer to generate ready-to-use YARA signatures for threat hunting.
Native Structure Parsing
We don't just identify the file; we parse its internal structure to highlight anomalies.
View all 14,000+ signaturesForensic Toolkit
View All ToolsHex Viewer
Inspect raw bytes and ASCII.
MIMEMIME Sniffer
Determine true file type.
ENTEntropy Calc
Detect encryption/packing.
METAEXIF Reader
Safely extract metadata.
B64Base64 Decoder
Decode payloads.
HASHHash Generator
MD5, SHA1, SHA256.
STRString Extractor
Dump ASCII/Unicode.
PERMChmod Calc
Unix permissions math.
Case Study: The Resume PDF
An HR department receives resume_2024.pdf. Standard antivirus scans show it as clean. Opening it in Adobe Reader executes embedded JavaScript that initiates a shellcode downloader.
The uViewFile workflow:
- Drag into Hex Viewer (isolated from OS parsers).
- MIME sniffer confirms magic number
25 50 44 46(PDF). - String extractor dumps the
/JavaScriptand/JSdictionary tags. - Entropy analysis shows a highly compressed block at offset 0x4B20.
- Analyst extracts the block safely for sandbox detonation.
Zero Data Collection
We do not run Google Analytics. We do not have a backend server processing your files. The entire application is a static bundle of HTML, CSS, and JS served over CDN.
Inspect the network tab. You'll see zero outbound requests when analyzing a file.
Reference Library
Format Specifications
vs. The Competition
| Feature | uViewFile | Native OS Viewer | Cloud Scanners |
|---|---|---|---|
| Privacy | 100% Local | Telemetry active | Uploads files |
| Execution Risk | Zero (Static) | High (Parsers) | Zero (Remote) |
| Offline Capability | Yes | Yes | No |
Who is this for?
Designed for SOC analysts, incident responders, malware reverse engineers, and privacy-conscious users who need to verify data integrity without relying on bloated, insecure desktop applications.
Stop guessing. Start analyzing.
Drop a file into the Hex Viewer immediately. No installation required.
Launch Viewer