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Hello, aspiring ethical hackers. In this blogpost, you will learn about DNS spoofing attack. Also known as DNS poisoning or DNS cache poisoning, in this attack a fake or wrong value are entered into the DNS cache. To understand this in detail, you have to first understand what is DNS, DNS server and DNS cache etc.

What is DNS?

Domain Name System (DNS) is a system that associates domain names with their IP addresses. For example, you want to go to a website named Alkapulka.com. When you open the browser and enter the domain name in the URL, your query first goes to a server that keeps a record of domain names and their IP addresses. Then this server takes you to the IP address associated with the alkapulka.com. This server is called the Domain Name System (DNS) server. A DNS server stores domain names and the IP addresses associated with these domain names in a cache known as DNS cache. Hence it is also known as DNS cache poisoning.

What is DNS spoofing?

Just imagine the IP address of the website alkapulka.com is xyx.xyz.xyx.xyz. Somehow the hacker takes control of the DNS server and registers the IP address of alkapulka.com to xyz.xyz.xyz.xyz where I am hosting a different website that looks similar to that of alkapulka.com. Now, when someone tries to visit alkapulka.com, instead of going to the original website, he will be redirected to the duplicate website controlled by the hacker.

Impact of DNS Spoofing

A hacker performs DNS spoofing to make unsuspecting users visit a malicious website. Once the user is one the malicious website, a lot of hacking attacks are possible. Some of them are,

1. Phishing:

Hackers may take unsuspecting users to a phishing website. Phishing is an act of presenting a fake page resembling the original webpage you intend to visit with the sole intention of stealing your credentials. Learn more about phishing.

2. Infecting with malicious software :

The website the users are redirected to may contain malware that can infect the user systems. Malware or malicious software is any software that performs malicious actions on a computer or mobile.

3. Gaining initial access:

Hackers can use multiple techniques to gain initial access on the system of the user. Learn more about gaining access.

How DNS spoofing attack can take place?

DNS spoofing can be achieved using many techniques like

1. Man in the Middle attack:

When attacker gets between the web browser and the DNS Server, he can perform DNS spoofing. Learn more about MiTM attack.

2. DNS server compromise:

If the DNS Server is compromised due to any vulnerability, then attacker gains access to the DNS cache, which he can manipulate as he want.

Hello, aspiring ethical hackers. In this blogpost, you will learn about a tool named MAC changer. In your ethical hacking journey there may be one day a need arise to change your MAC addresses. Although you can change your MAC addresses manually, mac changer is a tool that helps you to change it automatically. In our previous data link layer attacks, you learnt that communication in a LAN takes place with MAC addresses.

In our previous article on Data-link layer attacks, you have learnt what is a MAC address and its uses. Now, let’s see how to change your MAC addresses using MAC changer tool. To be able to change your MAC address first, you need to know your present MAC address. You can find out the MAC address of your machine using the command shown below.

ip a

You can see the current version of mac changes installed using the ‘-V’ option as show below.

You can see that each network adapter (NIC) attached to the system has one unique MAC address. You can also see your the MAC address of your device using MAC changer with the “-s” option.

macchanger -s <network interface>

If you want to see all the vendors that provide MAC addresses, using mac changer, the option is ‘-l’ as shown below.

macchanger -l

Before changing the MAC address of a adapter, make sure you disable that adapter using command as shown below.

sudo ip link set eth0 down

After making changes, you can enable the adapter using command shown below.

sudo ip link set eth0 up

Now, let’s see the different ways in which MAC addresses can be changed using mac changer. To give a random MAC address to a particular network adapter, say to the “eth0” adapter, the option we need to use is “-r”.

macchanger -r <interface>

To assign a random vendor MAC address of the same kind with mac changer, the option to use is “a”.

macchanger -a <interface>

To give a random MAC address of any kind, we can use the “-A” option.

macchanger -A <interface>

Every vendor has a unique MAC address that starts with unique vendor bytes. Using this tool, you can also change the MAC address without changing the vendor bytes using the “-e” option.

macchanger -e <interface>

You already know that MAC address is hardcoded to a hardware NIC card. Using this tool, you can also make your changed MAC addresses pretend as the burned in address of the NIC.

macchanger -b -r <interface>

That’s all about mac changer tool.

Hello, aspiring ethical hackers. In our previous blogposts, you learnt about Windows hacking techniques, Linux hacking techniques etc. In this blogpost, you will learn about BeEF tool that focuses on exploiting a software or program extensively used in both Linux and Windows operating systems. We are talking about web browser. BeEF is short for “The Browser Exploitation Framework”. It is a penetration testing tool focusing on the web browser.

In the noise of ever increasing cases of web server hacking and web application hacking, one that is often ignored is the exploitation of web clients, aka browser. Browsers once compromised, provide a easy way of gaining access to hackers. No doubt, attacks targeting web clients are on the rise. BeEF helps pen testers to understand the security posture of web browsers in an organization.

Let’s see how to use it. BeEF is present in the repositories of Kali Linux. We will be using the same for this tutorial. It can be installed on Kali as shown below.

After BeEF is successfully installed, don’t forget to run it with root privileges. Otherwise, it will not start.

After running for the first time, BeEF will ask you to setup a new password. Set it. Once you set it, it will start a web interface by default. Before that, it will display a hook as shown below.

Before you use BeEF further, you need to understand two terms related to it. They are,

1. Hook: A hook is something used to trap a browser.
2. Zombie: A trapped browser is known as a Zombie.

Once the web interface of BeEF opens, login with username “beef” and the password you set earlier.

Once you login, you will be greeted with the dashboard of BeEF. The interface can be divided into two parts. On the left, you will see hooked browsers section. All those browsers that are compromised by BeEF are shown here. On the right, you can see the general interface of BeEF.

It has three tabs. The “Logs” tab show all the activity happening with BeEF.

The “Zombies” tab, as you expected will display all the compromised browsers.

BeEF also has “Getting started” tab. Now, let’s see how to hook a browser. Browsers can be hooked by using the hooks shown at the beginning. You have to somehow make users click on this hook script. Of course, this requires social engineering.

For demonstration purpose, BeEF has two demo pages that work as hooks. One is basic and advanced. They can be found in “Getting Started” tab as highlighted in the above image. Here is the basic demo page and advanced demo page.

All we have to do is copy the links of the pages and make target users click on these links. As soon as they do it, the browser gets hooked as shown below.

When you click on the IP, the “current browser” tab opens, displaying general information about the target OS on which that browser is installed.

The “Current browser” tab opens a few sub-tabs of itself. You have seen about the “details” tab above. The “Logs” sub-tab shows all the logs belonging to the current browser.

The most powerful part of BeEF in its command section.

This section includes all the commands that can be executed on the target system.

For example, let’s execute a command “Detect Antivirus” as shown below. This command as its name suggests tries to detect if Antivirus is installed on target system or not. We can execute this module by clicking on “Execute” as shown below.

To see the result of the executed command, click on the command in history. It will display the result in command results window to the right.

In our case, it’s true that Antivirus is not installed on the target system. If you click on the “Zombies” tab you have learnt above earlier, your hooked browser can be seen, as shown below.

Hello, aspiring ethical hackers. In one of our previous blogposts, you have learnt in detail about steganography and types of steganography techniques. In this blogpost, you will learn about steghide, a tool that can perform image steganography and audio steganography.

Let’s see how this tool works. This tool is installed by default in Kali Linux. The command to use steghide is shown below. If it is not installed yet, the system will prompt you to install it as shown below.

After steghide is successfully installed, let’s get ready our files. To perform steganography, we need two files: a file we want to hide (hereby called as secret file to avoid confusion) and another file to hide this secret file. So, first let’s create file which we want to hide (I mean, secret file). Let’s create a text file named “secret.txt” with some text inside as shown below.

Now, we need a file in which we can hide this “secret.txt” file. With Steghide, we can hide secret data in JPEG, BMP and audio files of WAV and Au formats. For this tutorial, let’s just download a hot pic in jpeg format from Freepix as shown below. 

What can be hotter than an erupting volcano. Since both files are ready, we can start working with steghide. Here’s the command.

Here is the explanation of the options used:

–embed: for embedding a file into another (in this case, embedding secret.txt into volcano.jpg).

-ef: file that needs to be hidden or embedded

-cf: file in which the above file is to be hidden.

-sf: resultant file after embedding.

You can embed a file even without using the ‘-sf’ option but when you do that, the original file (in our case, volcano.jpg) will be overwritten. Steghide will ask you to set a password while embedding a file, you can continue without setting the password too, but that would make it easy for right people to see the secret message. This is the image with secret data hidden beside it.

It is looking just like any normal image, right. We can use steghide to specify additional options while embedding but before that let’s learn how to extract this secret data from the image file. To retrieve hidden data from the image file, we use the “extract” command of steghide is used.

You can even specify a separate file to extract the secret data from using the ‘-xf’ option below.

Whatever the case, you have to enter the correct password while extracting. Steghide also has a ‘info” command to display the information about the image file with secret data. Here it is how it works on a normal image file.

Now, let’s get information about our “volcano_with_secret.jpg file.

As you can see, steghide reveals that the above file (volcano_with_secret.jpg) is embedding a file named “secret.txt, it is compressed and encrypted with rijndael-128, cbc encryption. Now, let’s learn about additional options that can be used with steghide while embedding a file. We have seen while using “info” command that the name of the embedded file was displayed using the “-N” option, you can stop this name from being displayed.

Now, let’s observe this file using the “info” command as shown below.

As you can see, the name of the hidden file is not being displayed now. You can even encrypt a file with steghide using the “-z” option.

By default, steghide uses rijndael-128 cbc encryption to encrypt the file. We can even specify the encryption algorithm we want. The encryption algorithms supported by steghide can be viewed using the “encinfo” command.

We can set our own encryption algorithm we want using the ‘-e’ option. For example, let’s set the DES algorithm with cbc cipher.

That is how we use steghide to hide a file.