What Is the Magic Number in Cybersecurity?
Written by: Monica Burgess
Published: 7/13/2025
A classic example is the PNG file format. PNG files always begin with the hex code 89 50 4E 47, which corresponds to .PNG. This helps computers instantly distinguish PNGs from other image types.
If a file’s contents don’t align with its magic number, it’s flagged as suspicious. Your system or security software may block it to prevent potential harm.
Magic numbers confirm a file’s authenticity and type. This prevents attackers from disguising malicious files (like an executable) as safe-looking ones (like an image or document).
By relying on tools that use magic numbers under the hood, like antivirus programs or endpoint protection, users can avoid accidentally opening disguised files. Best practice? Be cautious and avoid running unknown files, even if they look legitimate.
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