Hi, I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written primarily for the benefit of the security area directors. Document editors and WG chairs should treat these comments just like any other last call comments. I am not altogether familiar with the placement of IMAP mailboxes to have a solid grasp on the subject. Please take my comments with a grain of salt. :) You mention at the end of Section 2 that users may configure shared mailboxes. Does that imply that mailboxes are not normally shared, and would then mean that another user would not have any access to any of the mailboxes identified by IMAP unless they were specifically given a common, shared mailbox? An example of my concern is that the \Junk mailbox may be configured to be common to all the users. In some cases, a legitimate piece of mail may be incorrectly marked as spam by a filter and then placed into the Junk bin. If that were to happen, anyone who had access to that mailbox would be able to see the contents of that email. If this could happen, then a line or two in the Security Considerations section to alert the reader to this potential threat would address my concern. Other than that, I find the document to be of good quality and ready to be discussed by the IESG. Thanks, Chris