Microsoft/MSN MARC archive
application/octet-stream
Magic Bytes
Offset: 0
4D 41 52 43
The Microsoft MARC archive is a proprietary container format developed by Microsoft Corporation for use within its legacy network services. This format was primarily employed by MSN Explorer and early Windows Live products to package software updates and application resources for efficient distribution. As an obsolete archive type no longer in active development, these files are rarely encountered in modern computing environments and generally pose minimal security risks.
Validation Code
How to validate .mar files in Python
Python
def is_mar(file_path: str) -> bool:
"""Check if file is a valid MAR by magic bytes."""
signature = bytes([0x4D, 0x41, 0x52, 0x43])
with open(file_path, "rb") as f:
return f.read(4) == signatureHow to validate .mar files in Node.js
Node.js
function isMAR(buffer: Buffer): boolean {
const signature = Buffer.from([0x4D, 0x41, 0x52, 0x43]);
return buffer.subarray(0, 4).equals(signature);
}
Go
func IsMAR(data []byte) bool {
signature := []byte{0x4D, 0x41, 0x52, 0x43}
if len(data) < 4 {
return false
}
return bytes.Equal(data[:4], signature)
}API Endpoint
GET
/api/v1/mar
curl https://filesignature.org/api/v1/mar