Canada Post hit by data breach after supplier ransomware attack. Canada Post has informed 44 of its large commercial customers that a ransomware attack on a third-party service provider exposed shipping information for their customers. ​Canada Post has informed 44 of its large commercial customers that a ransomware attack on a third-party service provider exposed shipping information for their customers. Canada Post is the primary postal operator in Canada, serving 16.5 million Canadian residential and business addresses. Third-party company: CommPort Communications.