Data should never have been on subcontractor's servers, says Customs and Border Protection.   Photos used by US Customs and Border Protection (CBP) in an effort to protect travelers have been taken in an attack against a federal subcontractor. Officials confirmed the compromise, which they described as part of a malicious cyberattack. While the agency declined to give details about the photos accessed by the attacker, the subcontractor is known to maintain databases of photos that include passport and visa photos, license plate images, and images from facial recognition systems. According to the agency, a subcontractor transferred CBP data to…