Sample XLS file (legacy workbook)

Handle it in code

Each snippet below was run against this exact file with Python 3.14.4 and Node 24.15.0 when this page was built, and the output shown is what it printed.

Python

Check for macros before accepting or opening an Office upload. Modern files are ZIPs: VBA lives in vbaProject.bin (Microsoft) or a Basic folder (OpenDocument). Legacy .xls/.doc files are OLE2 containers that need a dedicated parser, such as oletools, to see inside.

import zipfile

OLE2 = bytes.fromhex("d0cf11e0a1b11ae1")

with open("legacy-workbook.xls", "rb") as f:
    magic = f.read(8)
if magic == OLE2:
    print("legacy OLE2 file (.xls, .doc, .ppt, .msg): may carry VBA; inspect it with an OLE parser")
elif not zipfile.is_zipfile("legacy-workbook.xls"):
    print("not an Office file")
else:
    with zipfile.ZipFile("legacy-workbook.xls") as z:
        names = z.namelist()
        types = z.read("[Content_Types].xml").decode() if "[Content_Types].xml" in names else ""
    macros = [n for n in names if n.lower().endswith("vbaproject.bin") or n.startswith(("Basic/", "Scripts/"))]
    if macros or "macroEnabled" in types:
        print("contains macros:", ", ".join(macros) or "declared in [Content_Types].xml")
    else:
        print(f"no macro parts among {len(names)} entries")

Run against this file, it prints: legacy OLE2 file (.xls, .doc, .ppt, .msg): may carry VBA; inspect it with an OLE parser