Security

I finally found some time again to write a walk-through of a Hack The Box machine. In this post we’ll hack into Fuse, a Medium machine which just got retired and included some password guessing, discovery of stored plaintext credentials and eventually a SeLoadDriverPrivilege escalation. Recon and Enumeration To get a first overview of the box, we’ll start with a nmap -sC -sV 10.10.10.193. PORT STATE SERVICE VERSION 53/tcp open domain Simple DNS Plus 80/tcp open http Microsoft IIS httpd 10.0 | http-methods: |_ Potentially risky methods: TRACE |_http-server-header: Microsoft-IIS/10.0 |_http-title: Site doesn't have a title (text/html). 88/tcp open kerberos-sec Microsoft Windows Kerberos (server time: 2020-10-30 22:31:39Z) 135/tcp open msrpc Microsoft Windows RPC 139/tcp open netbios-ssn Microsoft Windows netbios-ssn 389/tcp open ldap Microsoft Windows Active Directory LDAP (Domain: fabricorp.local, Site: Default-First-Site-Name) 445/tcp open microsoft-ds Windows Server 2016 Standard 14393 microsoft-ds (workgroup: FABRICORP) 464/tcp open kpasswd5? 593/tcp open ncacn_http Microsoft Windows RPC over HTTP 1.0 636/tcp open tcpwrapped 3268/tcp open ldap Microsoft Windows Active Directory LDAP (Domain: fabricorp.local, Site: Default-First-Site-Name) 3269/tcp open tcpwrapped Looking at the ports and enumeration output, we can tell we’re dealing with a domain controller. ...

To boot Linux without Data Execution Prevention, so that the OS doesn’t mark certain memory regions as non-executable, we… 1.) … boot and enter the GRUB menu (hold Shift-key on boot*) 2.) … select the OS and press e to edit the commands and kernel parameters 3.) … add noexec=off and/or noexec32=off (depending on what you want) in the linux line 4.) … then boot with Ctrl-x ...

In a recent challenge I needed to get access to a system by exploiting the way Python deserializes data using the pickle module. In this article I want to give a quick introduction of how to pickle/unpickle data, highlight the issues that can arise when your program deals with data from untrusted sources and “dump” my own notes. For running the example code I’m using Python 3.8.2 on macOS 10.15; the demonstration of the reverse shell is just a connect-back to a loopback address. ...

After doing a couple more machines on Hack The Box, Bart was one that I definitely wanted to do a write-up for. We start with a bunch of web enumeration and discovering different directories and hostnames. Eventually, we discover a chat application, register our own user and do log poisoning to get our first low priv shell. Privilege escalation to Administrator is then accomplished by identifying AutoLogon credentials stored in the registry. On the way we read some source code, learn about 32/64-bit registry queries and running commands in a different user context. ...

In this write-up we’re looking at getting into the retired machine Kotarak from Hack the Box. Kotarak was a really fun box as it required lots of different techniques and was just a longer journey to root. Our first foothold comes via leaked credentials that we can retrieve using server side request forgery. These credentials give us admin access to a Tomcat manager application where we can upload our first reverse shell. From there, we get access to both a NTDS.DIT file and a Windows SYSTEM registry hive which we can leverage to extract user hashes. Cracking these hashes, we level up to another user and eventually use a vulnerability in wget to write our SSH key into the authorized_keys file on another (virtual) host and through that get access to the root flag on there. ...