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Network Services Pentesting
110,995 - Pentesting POP
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Basic Information

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

Enumeration

nc -nv <IP> 110
openssl s_client -connect <IP>:995 -crlf -quiet

Manual

You can use the command CAPA to obtain the capabilities of the POP3 server.

Automated

nmap --script "pop3-capabilities or pop3-ntlm-info" -sV -port <PORT> <IP> #All are default scripts
The pop3-ntlm-info plugin will return some "sensitive" data (Windows versions).

โ€‹POP3 bruteforceโ€‹

POP syntax

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
From hereโ€‹
Example:
[email protected]:~# telnet $ip 110
+OK beta POP3 server (JAMES POP3 Server 2.3.2) ready
USER billydean
+OK
PASS password
+OK Welcome billydean
โ€‹
list
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+OK 2 1807
1 786
2 1021
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retr 1
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+OK Message follows
Dear Billy Dean,
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Here is your login for remote desktop ... try not to forget it this time!
username: billydean
password: PA$W0RD!Z

HackTricks Automatic Commands

Protocol_Name: POP #Protocol Abbreviation if there is one.
Port_Number: 110 #Comma separated if there is more than one.
Protocol_Description: Post Office Protocol #Protocol Abbreviation Spelled out
โ€‹
Entry_1:
Name: Notes
Description: Notes for POP
Note: |
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.
โ€‹
https://book.hacktricks.xyz/pentesting/pentesting-whois
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Entry_2:
Name: Banner Grab
Description: Banner Grab 110
Command: nc -nv {IP} 110
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Entry_3:
Name: Banner Grab 995
Description: Grab Banner Secure
Command: openssl s_client -connect {IP}:995 -crlf -quiet
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Entry_4:
Name: Nmap
Description: Scan for POP info
Command: nmap --script "pop3-capabilities or pop3-ntlm-info" -sV -p 110 {IP}
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Entry_5:
Name: Hydra Brute Force
Description: Need User
Command: hydra -l {Username} -P {Big_Passwordlist} -f {IP} pop3 -V
Entry_6:
Name: consolesless mfs enumeration
Description: POP3 enumeration without the need to run msfconsole
Note: sourced from https://github.com/carlospolop/legion
Command: msfconsole -q -x 'use auxiliary/scanner/pop3/pop3_version; set RHOSTS {IP}; set RPORT 110; run; exit'
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