The document describes three types of attacks in the operation security domain: man-in-the-middle, where an intruder intercepts communication between two parties; mail bombing, which involves sending large volumes of emails to overwhelm a user's system; and war dialing, where hackers dial a series of numbers to identify and access devices. Each attack type poses significant threats, including compromising secure information, crashing user systems, and unauthorized access to services. The document highlights the seriousness of these security vulnerabilities.