1. IMAP is a popular protocol for users to retrieve e-mail from servers. It is likely supported by the mail client that you use, such as Netscape or Outlook. Key point: IMAP is important to hackers because many implementations are vulnerable to buffer overflow exploits. In particular, a popular distribution of Linux shipped with a vulnerable IMAP service that was enabled by default. Therefore, even today, security professionals frequently detect scans directed at port 143 looking for vulnerable IMAP servers. From Hacking-Lexicon