Post Office Protocol version 3 (POP3) is an mail protocol used to retrieve mail from a remote server to a local email client. POP3 copies the mail from the remote server into the local mail client. Optionally, mail is deleted after it is downloaded from the server. This saves space on the server.
If you frequently access your mail account from multiple devices/locations, POP3 may not be the best option for you since it is not able to synchronize your mailbox across multiple devices. However, POP3 is a very simple mail protocol making it less prone to errors and allows for a much easier implementation.
Ports used for POP3:
- Port 110 – Default POP3 port.
- Port 995 – POP3 port used for SSL/TLS.
Post Office Protocol (POP) is a type of computer networking and Internet standard protocol that extracts and retrieves email from a remote mail server for access by the host machine. POP is an application layer protocol in the OSI model that provides end users the ability to fetch and receive email (from here).The POP clients generally connect, retrieve all messages, store them on the client system, and delete them from the server. There are 3 versions of POP, but POP3 is the most used one.
Default ports: 110, 995(ssl)
PORT STATE SERVICE 110/tcp open pop3
nc -nv <IP> 110openssl s_client -connect <IP>:995 -crlf -quiet
You can use the command
CAPA to obtain the capabilities of the POP3 server.
nmap --script "pop3-capabilities or pop3-ntlm-info" -sV -port <PORT> <IP> #All are default scripts
pop3-ntlm-info plugin will return some “sensitive” data (Windows versions).
POP commands: USER uid Log in as "uid" PASS password Substitue "password" for your actual password STAT List number of messages, total mailbox size LIST List messages and sizes RETR n Show message n DELE n Mark message n for deletion RSET Undo any changes QUIT Logout (expunges messages if no RSET) TOP msg n Show first n lines of message number msg CAPA Get capabilities
root@kali:~# telnet $ip 110 +OK beta POP3 server (JAMES POP3 Server 2.3.2) ready USER billydean +OK PASS password +OK Welcome billydean list +OK 2 1807 1 786 2 1021 retr 1 +OK Message follows From: firstname.lastname@example.org Dear Billy Dean, Here is your login for remote desktop ... try not to forget it this time! username: billydean password: PA$$W0RD!Z
|auth_debug||Enables all authentication debug logging.|
|auth_debug_passwords||This setting adjusts log verbosity, the submitted passwords, and the scheme gets logged.|
|auth_verbose||Logs unsuccessful authentication attempts and their reasons.|
|auth_verbose_passwords||Passwords used for authentication are logged and can also be truncated.|
|auth_anonymous_username||This specifies the username to be used when logging in with the ANONYMOUS SASL mechanism.|