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Windows NT Registry and Registry Undo files (.sud)

.sud file signature | application/octet-stream

Windows NT Registry and Registry Undo files

Safe

Magic Bytes

Offset 0
52 45 47 45 44 49 54

Sources: Gary Kessler

Extension

.sud

MIME Type

application/octet-stream

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .sud files in Python

Python 
def is_sud(file_path: str) -> bool:
    """Check if file is a valid SUD by magic bytes."""
    signature = bytes([0x52, 0x45, 0x47, 0x45, 0x44, 0x49, 0x54])
    with open(file_path, "rb") as f:
        return f.read(7) == signature

How to validate .sud files in Node.js

Node.js 
function isSUD(buffer: Buffer): boolean {
  const signature = Buffer.from([0x52, 0x45, 0x47, 0x45, 0x44, 0x49, 0x54]);
  return buffer.subarray(0, 7).equals(signature);
}

How to validate .sud files in Go

Go 
func IsSUD(data []byte) bool {
    signature := []byte{0x52, 0x45, 0x47, 0x45, 0x44, 0x49, 0x54}
    if len(data) < 7 {
        return false
    }
    return bytes.Equal(data[:7], signature)
}

API Endpoint

GET /api/v1/sud
curl https://filesignature.org/api/v1/sud

See the full API documentation for all endpoints and parameters.

Frequently Asked Questions

What is a .sud file?

A .sud file is a Windows NT Registry and Registry Undo files file. Windows NT Registry and Registry Undo files

What are the magic bytes for .sud files?

The magic bytes for Windows NT Registry and Registry Undo files files are 52 45 47 45 44 49 54 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .sud file?

To validate a .sud file, read the first bytes of the file and compare them against the known magic bytes (52 45 47 45 44 49 54) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .sud files?

There is no officially registered MIME type for .sud files. Systems typically use application/octet-stream as a generic fallback when handling this format.

Is it safe to open .sud files?

Windows NT Registry and Registry Undo files (.sud) files are generally safe to open. They are classified as low risk because they primarily contain data rather than executable code. However, always ensure files come from a trusted source.