DLL
application/x-msdownload
⚠️
High Risk Format
This file type can contain executable code. Always validate source and scan with antivirus before opening.
Magic Bytes
Offset: 0
4D 5A
Dynamic Link Library (DLL) is a shared library format implementation developed and maintained by Microsoft Corporation for the Windows operating system. These files store modular code, data, and resources that multiple applications can access concurrently to optimize system memory and disk space. Because DLLs execute with the privileges of the calling application, they are frequently exploited through hijacking techniques and serve as common vectors for the distribution and execution of malware.
Validation Code
How to validate .dll files in Python
Python
def is_dll(file_path: str) -> bool:
"""Check if file is a valid DLL by magic bytes."""
signature = bytes([0x4D, 0x5A])
with open(file_path, "rb") as f:
return f.read(2) == signatureHow to validate .dll files in Node.js
Node.js
function isDLL(buffer: Buffer): boolean {
const signature = Buffer.from([0x4D, 0x5A]);
return buffer.subarray(0, 2).equals(signature);
}
Go
func IsDLL(data []byte) bool {
signature := []byte{0x4D, 0x5A}
if len(data) < 2 {
return false
}
return bytes.Equal(data[:2], signature)
}API Endpoint
GET
/api/v1/dll
curl https://filesignature.org/api/v1/dll