Null Byte How-Tos

How To: Abuse Vulnerable Sudo Versions to Get Root

Anyone who has used Linux long enough is familiar with sudo. Short for superuser do (or substitute user do, depending on who you ask), it allows users to run commands as either root or another user on the system. From a hacker's point of view, sudo is often all that stands between them and root access. We'll be exploring an older vulnerability in sudo that allows a user to run commands as root.

How To: Spy on SSH Sessions with SSHPry2.0

SSH, or the secure shell, is a way of controlling a computer remotely from a command-line interface. While the information exchanged in the SSH session is encrypted, it's easy to spy on an SSH session if you have access to the computer that's being logged in to. Using a tool called SSHPry, we can spy on and inject commands into the SSH sessions of any other user logged in to on the same machine.

How To: Brute-Force FTP Credentials & Get Server Access

Hackers often find fascinating files in the most ordinary of places, one of those being FTP servers. Sometimes, luck will prevail, and anonymous logins will be enabled, meaning anyone can just log in. But more often than not, a valid username and password will be required. But there are several methods to brute-force FTP credentials and gain server access.

How To: Use GoScan to Quickly Enumerate Networks & Services

Network enumeration is one of the essential phases of an attack, but it can take a lot of time and effort depending on the size. We've all been spoiled by Nmap and similar tools, and while there is a learning curve involved, they are extremely useful. But there's also GoScan, a tool that builds upon Nmap, offering an automated way to enumerate networks and services quickly.

How To: Find Exploits & Get Root with Linux Exploit Suggester

Privilege escalation is one of the essential skills a hacker can have and often separates the newbies from the pros. With a continually changing landscape and a plethora of exploits out there, it can be a problematic aspect of any attack. Luckily, some tools can help expedite the process. Linux Exploit Suggester is just one of many to help you get root.

How To: Exploit WebDAV on a Server & Get a Shell

The internet has undoubtedly changed the way we work and communicate. With technological advances, more and more people can collaborate on the web from anywhere in the world. But this remote-friendly environment inherently brings security risks, and hackers are always finding ways to exploit systems for other uses.

How To: Use Banner Grabbing to Aid in Reconnaissance

As we've seen with other tools and utilities, certain things that are typically used by administrators to do their job more efficiently are often abused by attackers for exploitation. After all, hacking is just the process of getting a computer to do things in unexpected ways. Today, we will be covering a variety of methods to perform banner grabbing to learn more about the target system.

How to Hack with Arduino: Building MacOS Payloads for Inserting a Wi-Fi Backdoor

Arduino is a language that's easy to learn and supported on many incredibly low-cost devices, two of which are the $2 Digispark and a $3 ESP8266-based board. We can program these devices in Arduino to hijack the Wi-Fi data connection of any unlocked macOS computer in seconds, and we can even have it send data from the target device to our low-cost evil access point.

How To: Hack Wi-Fi Networks with Bettercap

There are many tools out there for Wi-Fi hacking, but few are as integrated and well-rounded as Bettercap. Thanks to an impressively simple interface that works even over SSH, it's easy to access many of the most powerful Wi-Fi attacks available from anywhere. To capture handshakes from both attended and unattended Wi-Fi networks, we'll use two of Bettercap's modules to help us search for weak Wi-Fi passwords.

How To: Enumerate MySQL Databases with Metasploit

It's been said time and time again: reconnaissance is perhaps the most critical phase of an attack. It's especially important when preparing an attack against a database since one wrong move can destroy every last bit of data, which usually isn't the desired outcome. Metasploit contains a variety of modules that can be used to enumerate MySQL databases, making it easy to gather valuable information.

How To: Use SUDO_KILLER to Identify & Abuse Sudo Misconfigurations

Sudo is a necessity on most Linux systems, most of which are probably being used as web servers. While the principle of least privilege is typically applied, sudo misconfigurations can easily lead to privilege escalation if not properly mediated. Which brings us to SUDO_KILLER, a tool used to identify sudo misconfigurations that can aid in privilege escalation.

How To: Brute-Force SSH, FTP, VNC & More with BruteDum

Brute-forcing is an easy way of discovering weak login credentials and is often one of the first steps when a hacker finds network services running on a network they gain access to. For beginners and experienced hackers alike, it's useful to have access to the right tools to discover, classify, and then launch customized brute-force attacks against a target. BruteDum does it all from a single framework.

How To: Hack Apache Tomcat via Malicious WAR File Upload

Web applications are a prime target for hackers, but sometimes it's not just the web apps themselves that are vulnerable. Web management interfaces should be scrutinized just as hard as the apps they manage, especially when they contain some sort of upload functionality. By exploiting a vulnerability in Apache Tomcat, a hacker can upload a backdoor and get a shell.

How To: Get Started with MicroPython for ESP8266 Microcontrollers

For anyone interested in using cheap, Wi-Fi-connected microcontrollers like the ESP8266, the Arduino programming language can be a barrier to entry. Based on C++, Arduino requires knowledge of more computer science than languages like Python. Fortunately for beginners, setting up MicroPython on an ESP8266 allows anyone to write Python on affordable microcontrollers in a matter of minutes.

How To: Crack WPA & WPA2 Wi-Fi Passwords with Pyrit

Pyrit is one of the most powerful WPA/WPA2 cracking tools in a hacker's arsenal, with the ability to benchmark a computer's CPU speeds, analyze capture files for crackable handshakes, and even tap into GPU password-cracking power. To demonstrate how quickly it can hack a WPA/WPA2 password, we'll use it to play a Wi-Fi hacking CTF game anyone can practice for less than $10.

How To: Use John the Ripper in Metasploit to Quickly Crack Windows Hashes

There are many password-cracking tools out there, but one of the mainstays has always been John the Ripper. It's a powerful piece of software that can be configured and used in many different ways. Metasploit actually contains a little-known module version of JTR that can be used to quickly crack weak passwords, so let's explore it in an attempt to save precious time and effort.

How To: Find Hidden Web Directories with Dirsearch

One of the first steps when pentesting a website should be scanning for hidden directories. It is essential for finding valuable information or potential attack vectors that might otherwise be unseen on the public-facing site. There are many tools out there that will perform the brute-forcing process, but not all are created equally.

How To: Identify Missing Windows Patches for Easier Exploitation

No operating system is stricken with as many vulnerabilities as Windows, and it's often a race to release the latest patches to fix things. From an attacker's point of view, knowing which patches are present on a Windows machine can make or break successful exploitation. Today, we will be covering three methods of patch enumeration, using Metasploit, WMIC, and Windows Exploit Suggester.

How To: Get Root Filesystem Access via Samba Symlink Traversal

Samba can be configured to allow any user with write access the ability to create a link to the root filesystem. Once an attacker has this level of access, it's only a matter of time before the system gets owned. Although this configuration isn't that common in the wild, it does happen, and Metasploit has a module to easily exploit this security flaw.

How To: Hack UnrealIRCd Using Python Socket Programming

UnrealIRCd is an open-source IRC server that has been around since 1999 and is perhaps the most widely used one today. Version 3.2.8.1 was vulnerable to remote code execution due to a backdoor in the software. Today, we will be exploiting the vulnerability with Metasploit, examining the underlying code to understand it, and creating our own version of the exploit in Python.

How To: Securely Sniff Wi-Fi Packets with Sniffglue

Sniffing packets over a network is an easy way for hackers to gather information on a target without needing to do much work. But doing so can be risky if sniffing packets on an untrusted network because a payload within the packets being captured could be executed on your system. To prevent that, Sniffglue sandboxes packet sniffing to provide an extra layer of security.

How To: Quickly Gather Target Information with Metasploit Post Modules

Post-exploitation information gathering can be a long and drawn-out process, but it is an essential step when trying to pivot or establish advanced persistence. Every hacker should know how to enumerate a target manually, but sometimes it is worth it to automate the process. Metasploit contains post modules that can quickly gather valuable information about a target, saving both time and effort.

How To: Get Root with Metasploit's Local Exploit Suggester

So you've managed to get a shell on the target, but you only have measly low-level privileges. Now what? Privilege escalation is a vast field and can be one of the most rewarding yet frustrating phases of an attack. We could go the manual route, but like always, Metasploit makes it easy to perform local privilege escalation and get root with its exploit suggester module.

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