MS Publisher file subheader
application/octet-stream
Magic Bytes
Offset: 0
2D 2D 2D 2D 2D 42 45 47 49 4E 20 53 53 48 32 20 4B 45 59 2D 2D 2D 2D 2D
The SSH Public Key format is a cryptographic data structure standardized by the Internet Engineering Task Force for the Secure Shell protocol. It is primarily used for authenticating users to remote servers and establishing secure communication channels across networked systems. While it shares the .pub file extension with Microsoft Publisher documents, this specific format is a text-based structure and is considered safe as it contains no executable code.
Validation Code
How to validate .pub files in Python
Python
def is_pub(file_path: str) -> bool:
"""Check if file is a valid PUB by magic bytes."""
signature = bytes([0x2D, 0x2D, 0x2D, 0x2D, 0x2D, 0x42, 0x45, 0x47, 0x49, 0x4E, 0x20, 0x53, 0x53, 0x48, 0x32, 0x20, 0x4B, 0x45, 0x59, 0x2D, 0x2D, 0x2D, 0x2D, 0x2D])
with open(file_path, "rb") as f:
return f.read(24) == signatureHow to validate .pub files in Node.js
Node.js
function isPUB(buffer: Buffer): boolean {
const signature = Buffer.from([0x2D, 0x2D, 0x2D, 0x2D, 0x2D, 0x42, 0x45, 0x47, 0x49, 0x4E, 0x20, 0x53, 0x53, 0x48, 0x32, 0x20, 0x4B, 0x45, 0x59, 0x2D, 0x2D, 0x2D, 0x2D, 0x2D]);
return buffer.subarray(0, 24).equals(signature);
}
Go
func IsPUB(data []byte) bool {
signature := []byte{0x2D, 0x2D, 0x2D, 0x2D, 0x2D, 0x42, 0x45, 0x47, 0x49, 0x4E, 0x20, 0x53, 0x53, 0x48, 0x32, 0x20, 0x4B, 0x45, 0x59, 0x2D, 0x2D, 0x2D, 0x2D, 0x2D}
if len(data) < 24 {
return false
}
return bytes.Equal(data[:24], signature)
}API Endpoint
GET
/api/v1/pub
curl https://filesignature.org/api/v1/pub