crackajax

[MS-OFFCRYPTO] tools. Currently a validator for XLS passwords

crackajax

[MS-OFFCRYPTO] encryption tools (currently a password validator for XLS files)

npm install -g crackajax

$ crackajax password_protected_file.xls trial_password

will warn you if the file is not password protected, or print true/false.

In JS:

var crackajax = require('crackajax');
crackajax.verifyrc4(password, salt, verifier, verifier_hash)

For more details, consult MS-OFFCRYPTO