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LaCasaDePapel - Hack The Box

I had trouble with the OTP token on this box: I never figured out why but whenever I scanned the QR code with my Google Authenticator app it would always generate an invalid token. Using a Firefox add-on I was able to properly generate the token to get access to the page. As a nice twist, the login shell was changed to psysh so I couldn’t use the vsftpd exploit to get a full shell on the box. LaCasaDePapel has some typical HTB elements: scavenger hunt for SSH keys, base64 encoding and a cronjob running as root for final priv esc.

CTF - Hack The Box

This time it’s a very lean box with no rabbit holes or trolls. The box name does not relate to a Capture the Flag event but rather the Compressed Token Format used by RSA securid tokens. The first part of the box involves some blind LDAP injection used to extract the LDAP schema and obtain the token for one of the user. Then using the token, we are able to generate tokens and issue commands on the box after doing some more LDAP injection. The last part of the token was pretty obscure as it involved abusing the listfile parameter in 7zip to trick it into read the flag from root.txt. I was however not able to get a root shell on this box using this technique.

Friendzone - Hack The Box

Friendzone is an easy box with some light enumeration of open SMB shares and sub-domains. I used an LFI vulnerability combined with a writable SMB share to get RCE and a reverse shell. A cron job running as root executes a python script every few minutes and the OS module imported by the script is writable so I can modify it and add code to get a shell as root.

Hackback - Hack The Box

Hackback took me a long time to do. There are so many steps required just to get a shell. For extra difficulty, AppLocker is enabled and an outbound firewall policy is configured to block reverse shells. This box has a bit of everything: fuzzing, php, asp (for pivoting with reGeorg), command injection in a Powershell script, some light reversing. For the privesc, I used the diaghub vulnerability and modified an existing exploit to get a bind shell through netcat.

Netmon - Hack The Box

I think Netmon had the quickest first blood on HTB yet. The user flag could be grabbed by just using anonymous FTP and retrieving it from the user directory. I guessed the PRTG admin password after finding an old backup file and changing the year in the password from 2018 to 2019. Once inside PRTG, I got RCE as SYSTEM by creating a sensor and using Nishang’s reverse shell oneliner.

Querier - Hack The Box

To solve Querier, we find an Excel spreadsheet that contains a VBA macro then use Responder to capture NTLM hashes from the server by forcing it to connect back to our machine with xp_dirtree. After cracking the hash, we gain RCE on the server by using the standard xp_cmdshell command. The Administator credentials are found in a Group Policy Preference file.

Flujab - Hack The Box

Flujab was without a doubt one of the toughest HTB box. It’s got a ton of vhosts that force you to enumerate a lot of things and make sure you don’t get distracted by the quantity of decoys and trolls left around. The key on this box is to stay ‘in scope’ as the box author hinted at before the box was released, so that means enumerating two specific domains without getting distracted by all the other stuff on the box.

Help - Hack The Box

Help showed that a small programming mistake in a web application can introduce a critical security vulnerability. In this case, the PHP application errors out when uploading invalid extensions such as PHP files but it doesn’t delete the file. Combined with a predictable filename generated based on MD5 of original file + epoch, we can get RCE.

Sizzle - Hack The Box

Sizzle was an amazing box that requires using some Windows and Active Directory exploitation techniques such as Kerberoasting to get encrypted hashes from Service Principal Names accounts. The privesc involves adding a computer to domain then using DCsync to obtain the NTLM hashes from the domain controller and then log on as Administrator to the server using the Pass-The-Hash technique.

Chaos - Hack The Box

Chaos starts with some enumeration to find a hidden wordpress site that contains a set of credentials for a webmail site. There’s some simple crypto we have to do to decrypt an attachment and find a hidden link on the site. We then exploit the PDF creation website which uses LaTeX and gain RCE. After getting a reverse shell, we do some digging into the user’s folders and find the webmin root credentials stored in the Firefox user profile.