XLA
application/vnd.ms-excel
Magic Bytes
Offset: 2080
4D 69 63 72 6F 73 6F 66 74 20 45 78 63 65 6C 20 35 2E 30 20 57 6F 72 6B 73 68 65 65 74
The Microsoft Excel Add-In (XLA) is a legacy binary file format developed by Microsoft for extending the capabilities of the Excel spreadsheet environment. These files are primarily utilized to package custom functions, macros, and automation tools that integrate directly into the application's interface. While replaced by the modern XML-based XLAM format in later versions, XLA remains compatible with current software but necessitates caution due to its potential for embedded macro execution.
Validation Code
How to validate .xla files in Python
Python
def is_xla(file_path: str) -> bool:
"""
Check if file is a valid XLA by magic bytes.
Signature offset: 2080 bytes
"""
signature = bytes([0x4D, 0x69, 0x63, 0x72, 0x6F, 0x73, 0x6F, 0x66, 0x74, 0x20, 0x45, 0x78, 0x63, 0x65, 0x6C, 0x20, 0x35, 0x2E, 0x30, 0x20, 0x57, 0x6F, 0x72, 0x6B, 0x73, 0x68, 0x65, 0x65, 0x74])
with open(file_path, "rb") as f:
f.seek(2080)
return f.read(29) == signatureHow to validate .xla files in Node.js
Node.js
function isXLA(buffer: Buffer): boolean {
// Signature offset: 2080 bytes
const signature = Buffer.from([0x4D, 0x69, 0x63, 0x72, 0x6F, 0x73, 0x6F, 0x66, 0x74, 0x20, 0x45, 0x78, 0x63, 0x65, 0x6C, 0x20, 0x35, 0x2E, 0x30, 0x20, 0x57, 0x6F, 0x72, 0x6B, 0x73, 0x68, 0x65, 0x65, 0x74]);
if (buffer.length < 2109) return false;
return buffer.subarray(2080, 2109).equals(signature);
}
Go
func IsXLA(data []byte) bool {
// Signature offset: 2080 bytes
signature := []byte{0x4D, 0x69, 0x63, 0x72, 0x6F, 0x73, 0x6F, 0x66, 0x74, 0x20, 0x45, 0x78, 0x63, 0x65, 0x6C, 0x20, 0x35, 0x2E, 0x30, 0x20, 0x57, 0x6F, 0x72, 0x6B, 0x73, 0x68, 0x65, 0x65, 0x74}
if len(data) < 2109 {
return false
}
return bytes.Equal(data[2080:2109], signature)
}API Endpoint
GET
/api/v1/xla
curl https://filesignature.org/api/v1/xla