Microsoft Office Open XML Format
application/octet-stream
Magic Bytes
Offset: 0
50 4B 03 04 50 4B 05 06 50 4B 07 08
Microsoft PowerPoint Open XML (PPTX) is a presentation file format developed by Microsoft as part of the Office Open XML standard. It is primarily utilized for creating, sharing, and displaying electronic slide presentations containing text, graphics, and multimedia elements. Superseding the legacy binary PPT format, PPTX files utilize a compressed XML structure; while generally secure, they can contain embedded macros or external links that require careful security validation when sourced from untrusted or unknown originators.
Validation Code
How to validate .pptx files in Python
Python
def is_pptx(file_path: str) -> bool:
"""Check if file is a valid PPTX by magic bytes."""
signature = bytes([0x50, 0x4B, 0x03, 0x04, 0x50, 0x4B, 0x05, 0x06, 0x50, 0x4B, 0x07, 0x08])
with open(file_path, "rb") as f:
return f.read(12) == signatureHow to validate .pptx files in Node.js
Node.js
function isPPTX(buffer: Buffer): boolean {
const signature = Buffer.from([0x50, 0x4B, 0x03, 0x04, 0x50, 0x4B, 0x05, 0x06, 0x50, 0x4B, 0x07, 0x08]);
return buffer.subarray(0, 12).equals(signature);
}
Go
func IsPPTX(data []byte) bool {
signature := []byte{0x50, 0x4B, 0x03, 0x04, 0x50, 0x4B, 0x05, 0x06, 0x50, 0x4B, 0x07, 0x08}
if len(data) < 12 {
return false
}
return bytes.Equal(data[:12], signature)
}API Endpoint
GET
/api/v1/pptx
curl https://filesignature.org/api/v1/pptx