Thomson Reuters UltraTax CS 2017 on Windows, in a client/server configuration, transfers customer records and bank account numbers in cleartext over SMBv2, which allows attackers to (1) obtain sensitive information by sniffing the network or (2) conduct man-in-the-middle (MITM) attacks via unspecified vectors. The customer record transferred in cleartext contains: Client ID, Full Name, Spouse's Full Name, Social Security Number, Spouse's Social Security Number, Occupation, Spouse's Occupation, Daytime Phone, Home Phone, Tax Preparer, Federal and State Taxes to File, Bank Name, Bank Account Number, and possibly other sensitive information.