Spam email campaigns cannot do any damage without manual intervention by users who are encouraged to perform certain tasks How do spam campaigns infect computers? Unfortunately, due to the lack of knowledge of these threats and careless behaviour, many users inadvertently help scammers to achieve their goals. As mentioned above, emails of this type contain malicious attachments that infect computers only if opened. For example, if the attached file is an executable (.exe) file, it first needs to be executed (run) for it to install malicious programs. If the attachment is an MS Office document, when opened, it will request permission to enable macro commands.