ELF file signature
A ELF executable file begins with the bytes 7F 45 4C 46 (.ELF in ASCII) at the start of the file. The signature is the same whatever the file is named, which is why a renamed or extensionless ELF file is still recognisable.
Signature
| Offset | Hex | ASCII |
|---|---|---|
| 0 | 7F 45 4C 46Byte 4 is 01 for 32-bit or 02 for 64-bit; byte 5 is endianness. | .ELF |
MIME type: application/x-executable
How to check a file's signature
Without installing anything: drop the file on our detector. It reads the bytes in your browser and shows the hex dump alongside the verdict; nothing is uploaded.
macOS and Linux (Terminal):
xxd -l 32 file
file fileWindows (PowerShell):
Format-Hex -Path file -Count 32If the bytes do not match
A file named elf whose first bytes are something else is not a ELF file. The common explanations are a wrong or deliberately misleading extension, a download that saved an HTML error page instead of the file, or a container such as ZIP wrapping the real content. The detector reports what the bytes say; the ELF guide explains what a genuine file should contain.