Synchronising email: IMAP(Internet Message Access Protocol)

Synchronised mailbox across multiple devices

The IMAP protocol commands are more complicated than the POP3 protocol commands.

IMAP requires each command to be preceded by a random string to be able to track the reply. So we added c1, then c2, and so on

• c1LOGIN <username> <password> authenticates the user

• c2SELECT <mailbox> selects the mailbox folder to work with

• c3FETCH <mail_number> <data_item_name> Example fetch 3 body[] to fetch message number 3, header and body.

• c4MOVE <sequence_set> <mailbox> moves the specified messages to another mailbox

• c5COPY <sequence_set> <data_item_name> copies the specified messages to another mailbox

• c6LOGOUT logs out

An example of user 'strategos' retrieving an email :

User@TryHackMe$ telnet 10.10.41.192 143
Trying 10.10.41.192...
Connected to 10.10.41.192.
Escape character is '^]'.
* OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE LITERAL+ STARTTLS AUTH=PLAIN] Dovecot (Ubuntu) ready.
A LOGIN strategos
A OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS THREAD=ORDEREDSUBJECT MULTIAPPEND URL-PARTIAL CATENATE UNSELECT CHILDREN NAMESPACE UIDPLUS LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC ESEARCH ESORT SEARCHRES WITHIN CONTEXT=SEARCH LIST-STATUS BINARY MOVE SNIPPET=FUZZY PREVIEW=FUZZY PREVIEW STATUS=SIZE SAVEDATE LITERAL+ NOTIFY SPECIAL-USE] Logged in
B SELECT inbox
* FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
* OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft \*)] Flags permitted.
* 4 EXISTS
* 0 RECENT
* OK [UNSEEN 2] First unseen.
* OK [UIDVALIDITY 1719824692] UIDs valid
* OK [UIDNEXT 5] Predicted next UID
B OK [READ-WRITE] Select completed (0.001 + 0.000 secs).
C FETCH 3 body[]
* 3 FETCH (BODY[] {445}
Return-path: <[e-mail]>
Envelope-to: [e-mail]
Delivery-date: Thu, 27 Jun 2024 16:19:35 +0000
Received: from [10.11.81.126] (helo=client.thm)
        by example.thm with smtp (Exim 4.95)
        (envelope-from <[e-mail]>)
        id 1sMrpq-0001Ah-UT
        for [e-mail];
        Thu, 27 Jun 2024 16:19:35 +0000
From: [e-mail]
To: [e-mail]
Subject: Telnet email

Hello. I am using telnet to send you an email!
)
C OK Fetch completed (0.001 + 0.000 secs).
D LOGOUT
* BYE Logging out
D OK Logout completed (0.001 + 0.000 secs).
Connection closed by foreign host.