Windows icon file (.ico)
.ico file signature | image/vnd.microsoft.icon
Computer iconencoded inICO file format[8]
Magic Bytes
Offset 0
00 00 01 00
Sources: Apache Tika, Wikipedia, Gary Kessler, Neil Harvey FileSignatures
All Known Signatures
2 signature variants are documented for .ico files across multiple sources.
| Hex Signature | Offset | Sources |
|---|---|---|
| 00 00 01 00 | 0 | Apache Tika, Wikipedia, Gary Kessler, Neil Harvey FileSignatures |
| 42 41 28 00 00 00 2E 00 00 00 00 00 00 00 | 0 | Apache Tika |
Extension
.ico
MIME Type
image/vnd.microsoft.icon
Byte Offset
0
Risk Level
Safe
Validation Code
How to validate .ico files in Python
def is_ico(file_path: str) -> bool:
"""Check if file is a valid ICO by magic bytes."""
signature = bytes([0x00, 0x00, 0x01, 0x00])
with open(file_path, "rb") as f:
return f.read(4) == signatureHow to validate .ico files in Node.js
function isICO(buffer: Buffer): boolean {
const signature = Buffer.from([0x00, 0x00, 0x01, 0x00]);
return buffer.subarray(0, 4).equals(signature);
}How to validate .ico files in Go
func IsICO(data []byte) bool {
signature := []byte{0x00, 0x00, 0x01, 0x00}
if len(data) < 4 {
return false
}
return bytes.Equal(data[:4], signature)
}API Endpoint
/api/v1/ico
curl https://filesignature.org/api/v1/ico
See the full API documentation for all endpoints and parameters.
Frequently Asked Questions
What is a .ico file?
A .ico file is a Windows icon file file. Computer iconencoded inICO file format[8]
What are the magic bytes for .ico files?
The magic bytes for Windows icon file files are 00 00 01 00 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.
How do I validate a .ico file?
To validate a .ico file, read the first bytes of the file and compare them against the known magic bytes (00 00 01 00) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.
What is the MIME type for .ico files?
The primary MIME type for .ico files is image/vnd.microsoft.icon.
Is it safe to open .ico files?
Windows icon file (.ico) 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.