[原文]The new account wizard in Mail.app 2.0 in Mac OS 10.4, when configuring an IMAP mail account and checking the credentials, does not prompt the user to use SSL until after the password has already been sent, which causes the password to be sent in plaintext.
Apple Mac OS X Mail Account Wizard Login Credential Disclosure
Remote / Network Access
Loss of Confidentiality
Mac OS X contains a flaw that may lead to an unauthorized password exposure. The problem is that the Mail account wizard does not prompt the user to use SSL when configuring an IMAP mail account and checking the login credentials. This may allow a remote attacker to gain access to plaintext passwords, resulting in a loss of confidentiality.
Currently, there are no known upgrades, patches, or workarounds available to correct this issue.