SMTP

sudo nmap --script smtp-enum-users -p25 <IP>
sudo nmap --script smtp-open-relay,smtp-commands,smtp-ntlm-info -p25 <IP>

## ------------------| smtp-user-enum
smtp-user-enum -M VRFY -U /usr/share/seclists/Usernames/Names/names.txt -t 10.10.10.17
smtp-user-enum -U /usr/share/seclists/Usernames/Honeypot-Captures/multiplesources-users-fabian-fingerle.de.txt -m 50 -M RCPT -D humongousretail.com -t 10.10.10.17

## ------------------| Metasploit
msfconsole
use auxiliary/scanner/smtp/smtp_enum
set RHOSTS <IP>
set USER_FILE /usr/share/seclists/Usernames/Names/names.txt
set THREADS 10
set RPORT 25
run

## ------------------| Bash Script
for i in $(cat /usr/share/seclists/Usernames/Names/names.txt);do echo -e "HELO test.com\nVRFY $i\nQUIT" | nc -nv <IP> 25 | grep -E "250|550"; done

telnet <IP>  587
EHLO mailserver.com
AUTH LOGIN
<Username_in_base64> # echo -n "username" | base64
<Password_in_base64> # echo -n "password" | base64

## !! Be aware about from address. If you are using same domain for both from and to. they will ask auth. So please use [email protected] first !!
## ------------------| Using Swaks
swaks --from [email protected] --to [email protected] --header 'Subject: Hello world' --body 'This is msg body' --server 10.10.10.197

## ------------------| Using sendEmail
sendEmail -m 'Hello machan' -f [email protected]  -t [email protected] -s <IP> -u "Message Subject" -a attachment.pdf
sendEmail -o message-file=message.txt -f [email protected]  -t [email protected] -s <IP> -u "Message Subject" -a attachment.pdf

## ------------------| Using Telnet
telnet <IP> 25
HELO writer.htb
MAIL FROM:[email protected]
RCPT TO:[email protected]
DATA
Subject: Test mail
Hello h4rith
.
QUIT

## ------------------| Using NetCat
nc <IP> 25
HELO writer.htb
MAIL FROM:[email protected]
RCPT TO:[email protected]
DATA
Subject: Test mail
Hello h4rith
.
QUIT

## ------------------| Using NodeJS
const nodemailer = require('nodemailer');

const transporter = nodemailer.createTransport({
  host: 'smtp.example.com',       // Your provider's SMTP server
  port: 587,                      // Common: 587 (STARTTLS), 465 (SSL), 25 (non-auth, old)
  secure: false,                  // true for 465, false for other ports
  auth: {
    user: '[email protected]',       // Your email address
    pass: 'your_password_or_app_password'
  }
});

// Optional: For self-signed certs or debugging
// tls: {
//   rejectUnauthorized: false
// }

const mailOptions = {
  from: '"HarithD" <[email protected]>',
  to: '[email protected]',
  subject: 'SMTP Test',
  text: 'Test email',
  // html: '<p>HTML body with <strong>custom SMTP</strong></p>'
};

transporter.sendMail(mailOptions, (error, info) => {
  if (error) {
    return console.error('Send error:', error);
  }
  console.log('Email sent:', info.response);
});

## ------------------| Using smtpd (deprecated)
import smtpd
import asyncore

class CustomSMTPServer(smtpd.SMTPServer):
    def __init__(self, localaddr, remoteaddr):
        smtpd.SMTPServer.__init__(self, localaddr, remoteaddr)

    def process_message(self, peer, mailfrom, rcpttos, data):
        print('Received email from:', mailfrom)
        print('To:', rcpttos)
        print('Message:', data)

server = CustomSMTPServer(('0.0.0.0', 1025), None)
asyncore.loop()

## ------------------| Using asyncio
import asyncio
from aiosmtpd.controller import Controller

class CustomSMTPHandler:
    async def handle_RCPT(self, server, session, envelope, address, rcpt_options):
        envelope.rcpt_tos.append(address)
        return '250 OK'

    async def handle_DATA(self, server, session, envelope):
        print('Received email from:', envelope.mail_from)
        print('To:', envelope.rcpt_tos)
        print('Message:', envelope.content.decode('utf-8'))
        return '250 OK'

async def main(loop):
    handler = CustomSMTPHandler()
    controller = Controller(handler, hostname='localhost', port=1025)
    controller.start()

loop = asyncio.get_event_loop()
loop.run_until_complete(main(loop))