Backward compatibility with LAN Manager

Backward compatibility with LAN Manager. Here is NT's Achilles' heel: Backward compatibility with LAN Manager made possible some of NT's most notorious security breaches, such as password cracking, sniffing, and Server Message Block (SMB) man-in-the-middle attacks. NT has fairly well designed authentication and password protection techniques. However, NT renders these techniques pointless, because NT's default behavior is to use the corresponding LAN Manager techniques to provide backward compatibility with LAN Manager.