Alureon is a trojan and rootkit created to steal data by intercepting a system's network traffic and searching for banking usernames and passwords, credit card data, PayPal information, social security numbers, and other sensitive user data. Following a series of customer complaints, Microsoft determined that Alureon caused a wave of BSoDs on some 32-bit Microsoft Windows systems. The update, MS10-015, triggered these crashes by breaking assumptions made by the malware author(s).