Top System Related Commands In Linux With Descriptive Definitions

Commands are just like an instructions given to a system to do something and display an output for that instruction. So if you don't know how to gave an order to a system to do a task then how it can do while you don't know how to deal with. So commands are really important for Linux users. If you don't have any idea about commands of Linux and definitely you also don't know about the Linux terminal. You cannot explore Linux deeply. Because terminal is the brain of the Linux and you can do everything by using Linux terminal in any Linux distribution. So, if you wanna work over the Linux distro then you should know about the commands as well.
In this blog you will get a content about commands of Linux which are collectively related to the system. That means if you wanna know any kind of information about the system like operating system, kernel release information, reboot history, system host name, ip address of the host, current date and time and many more.

Note:

If you know about the command but you don't have any idea to use it. In this way you just type the command, then space and then type -h or --help or ? to get all the usage information about that particular command like "uname" this command is used for displaying the Linux system information. You don't know how to use it. Just type the command with help parameter like: uname -h or uname --help etc.

uname 

The "uname" is a Linux terminal command responsible of displaying the information about Linux system. This command has different parameter to display a particular part of information like kernel release (uname -r) or all the information displayed by typing only one command (uname -a).

uptime

This command is used to show how long the system has been running and how much load on it at current state of the CPU. This command is very useful when you system slows down or hang etc and you can easily get the info about the load on the CPU with the help of this command.

hostname

The "hostname" is the the command in Linux having different parameters to display the information bout the current host which is running the kernel at that time. If you wanna know about the parameters of hostname command then you just type hostname --help or hostname -h to get all the info about the command and the usage of the command.

last reboot

The "last reboot" is the command in Linux operating system used to display the reboot history. You just have to type this command over the Linux terminal it will display the reboot history of that Linux system.

date

The "date" is the command used in Linux operating system to show the date of the day along with the current time of the day.

cal

The "cal" command in Linux used to display the calendar which has the current date highlighted with a square box along with a current month dates and days just like a real calendar.

w

The "w" is the command used in Linux distro for the sake of getting the information about current user. If you type this command it will display who is online at the time.

whoami

The "whoami" is the command in Linux operating system used to show the information that who you are logged in as. For example if you are logged in as a root then it'll display "root" etc.

finger user

The "finger user" is the command used in Linux distribution to display the information about user which is online currently over that Linux system.

More information

• Hacker Lab
• Pentest Tools
• Hackerone
• Pentest With Kali Linux
• Hacking Images
• Hacking With Python
• Pentest Vs Ethical Hacking

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.  

Related links

1. Pentest Plus
2. Pentest Ios
3. Pentest Owasp Top 10
4. Hacking Apps
5. Pentest Wifi
6. Hacking Apps
7. Hacker Keyboard
8. Pentest Framework
9. Hacking Books
10. Pentest Red Team
11. How To Pentest A Website With Kali
12. Pentest Distro
13. Pentest Lab Setup
14. Pentest Book

Nmap: Getting Started Guide

Nmap is a free utility tool for network discovery, port scanning and security auditing, even though we can use it for more than that but in this article we will learn how to do these three things with nmap.

The original author of nmap is Gordon Lyon (Fyodor). Nmap is licensed under GPL v2 and has available ports in many different languages. Nmap is available for Linux, Windows, and Mac OS X. You can download your copy of nmap from their website.

Lets get started with nmap.

When performing pentests we always look for networks we are going to attack. We need to identify live hosts on the network so that we can attack them. There are plenty of tools available for finding live hosts on a network but nmap is one of the best tools for doing this job.

Lets start with simple host (target) discovery scans i,e scans that will tell us which ip address is up on our target network. Those ip addresses which are up on our target network are the ones that are assigned to a device connected on our target network. Every device on the network is going to have a unique ip address.
To perform a simple host discovery scan we use the following command

nmap -v -sn 10.10.10.0/24

flags we used in the above command are
-v for verbose output
-sn to disable port scan (we don't want to scan for ports right now)

Following the flags is the ip address of the target network on which we want to look for live hosts. The /24 at the end of the ip address is the CIDR that specifies the subnet of the network on which we are looking for live hosts.

After running the above command you should get a list of live hosts on your target network.
If you just want to know the list of ip addresses your command is going to scan, you can use the -sL flag of the nmap like this.

nmap -sL 10.10.10.0/24

this command will simply output the list of ip addresses to scan.

We sometimes want to do dns resolution (resolving ip addresses to domain names) when performing our network scans and sometimes we don't want dns resolution. While performing a host discovery scan with nmap if we want to perform dns resolution we use -R flag in our command like this:

nmap -v -sn -R 10.10.10.0/24

And if we don't want to perform dns resolution of hosts during our scan we add the -n flag to our command like this:

nmap -v -sn -n 10.10.10.0/24

After we have discovered the hosts that are up on our target network, we usually put the ip addresses of these hosts into a file for further enumeration.

Next step in our enumeration would be to detect which operating system and which ports are running on these live hosts, for that we run this command:

nmap -O -v 10.10.10.119

here we use -O (capital o not zero) for operating system detection and by default nmap performs SYN Scan for port discovery. However nmap scans for 1000 ports only by default of a particular host.

To make nmap go over a list of ip addresses in a file we use -iL flag like this:

nmap -O -v -iL targetlist

where targetlist is the name of the file which contains ip addresses that we want to perform port scan on.

To make nmap scan all the ports of a target we use the -p flag like this:

nmap -p- -v 10.10.10.121

We can also specify a range of ports using the -p flag like this:

nmap -p1-500 -v 10.10.10.121

here 1-500 means scan all the ports from 1 to 500.

We can use a number of scan techniques to discover open ports on our network but I will only discuss some of them for brevity.

We can perform a TCP SYN scan using nmap with -sS flag like this:

nmap -sS -v 10.10.10.150

We have also flags for TCP connect and ACK scans which are -sT -sA

nmap -sT -v 10.10.10.150

nmap -sA -v 10.10.10.150

We can also perform UDP scan as well instead of TCP scan using -sU flag

nmap -sU -v 10.10.10.150

We can perform TCP Null, FIN, and Xmas scans using the flags -sN, -sF, -sX

nmap -sN -v 10.10.10.150

nmap -sF -v 10.10.10.150

nmap -sX -v 10.10.10.150

If you don't know what these scans are then please visit Port Scanning Techniques and Algorithms for explanation.

After discovering the open ports on our target host, we want to enumerate what services are running on those open ports. To enumerate services and versions information on open ports we use the -sV flag like this:

nmap -sV -v 10.10.10.118

This should give us information about what services are running on what ports and what versions of those services are running on the target host.

nmap has an interesting feature called NSE nmap scripting engine. It allows users to write their own scripts, using the Lua programming language, to automate a wide variety of networking tasks. nmap ships with a diverse set of scripts which are very helpful to enumerate a target. To use the nmap default set of scripts while enumerating the target, we use the -sC flag like this:

nmap -sC -sV -v 10.10.10.118

We can also save the results of our nmap scans to a file using the -o flag like this

nmap -sC -sV -v -oA defaultscan 10.10.10.119

here -oA tells the nmap to output results in the three major formats at once and defaultscan is the name of the file that will be prepended to all the three output files.

This is the end of this short tutorial see you next time.

References:
https://nmap.org/book/scan-methods-null-fin-xmas-scan.html

Related links

• Pentest Jobs
• Hacking Growth
• Pentest Companies
• Hacking Hardware
• Pentest Hardware
• Basic Pentest 1 Walkthrough
• Hacking Lab
• Rapid7 Pentest
• Pentest Environment
• Hacking Games Online

Vsftpd Backdoor - Ekoparty Prectf - Amn3S1A Team

It's a 32bits elf binary of some version of vsftpd, where it have been added a backdoor, they don't specify is an authentication backdoor, a special command or other stuff.

I started looking for something weird on the authentication routines, but I didn't found anything significant in a brief period of time, so I decided to do a bindiff, that was the key for locating the backdoor quickly. I do a quick diff of the strings with the command "strings bin | sort -u" and "vimdiff" and noticed that the backdoored binary has the symbol "execl" which is weird because is a call for executing elfs, don't needed for a ftp service, and weird that the compiled binary doesn't has that symbol.

Looking the xrefs of "execl" on IDA I found that code that is a clear backdoor, it create a socket, bind a port and duplicate the stdin, stdout and stderr to the socket and use the execl:

There are one xrefs to this function, the function that decides when trigger that is that kind of systems equations decision:

The backdoor was not on the authentication, it was a special command to trigger the backdoor, which is obfuscated on that systems equation, it was no needed to use a z3 equation solver because is a simple one and I did it by hand.

The equation:

cmd[0] = 69

cmd[1] = 78

cmd[1] + cmd[2] = 154

cmd[2] + cmd[3] = 202

cmd[3] + cmd[4] = 241

cmd[4] + cmd[5] = 233

cmd[5] + cmd[6] = 217

cmd[6] + cmd[7] = 218

cmd[7] + cmd[8] = 228

cmd[8] + cmd[9] = 212

cmd[9] + cmd[10] = 195

cmd[10] + cmd[11] = 195

cmd[11] + cmd[12] = 201

cmd[12] + cmd[13] = 207

cmd[13] + cmd[14] = 203

cmd[14] + cmd[15] = 215

cmd[15] + cmd[16] = 235

cmd[16] + cmd[17] = 242

The solution:

cmd[0] = 69

cmd[1] = 75

cmd[2] = 79

cmd[3] = 123

cmd[4] = 118

cmd[5] = 115

cmd[6] = 102

cmd[7] = 116

cmd[8] = 112

cmd[9] = 100

cmd[10] = 95

cmd[11] = 100

cmd[12] = 101

cmd[13] = 106

cmd[14] = 97                    

cmd[15] = 118

cmd[16] = 117

cmd[17] = 125

The flag:

EKO{vsftpd_dejavu}

The binary:
https://ctf.ekoparty.org/static/pre-ekoparty/backdoor

Related articles

1. Hacking Gif
2. Pentest Uk
3. Pentesting And Ethical Hacking
4. Hacker0Ne
5. Pentest Cyber Security
6. Pentest Vs Red Team
7. Pentest Meaning
8. Pentest Enumeration
9. Pentest With Kali
10. Pentest Vs Ethical Hacking
11. Hacking Linux

Evolving Logic Until Pass Tests Automatically

Automating the automation is still a challenge, but in some cases it's possible under certain situations.

In 2017 I created logic-evolver, one of my experiments for creating logic automatically or better said evolving logic automatically.

In some way, the computer create its own program that satisfies a set of tests defined by a human.

https://github.com/sha0coder/logic-evolver

This implementation in rust, contains a fast cpu emulator than can execute one million instructions in less than two seconds. And a simple genetic algorithm to do the evolution.


Here we create the genetic algorithm, and configure a population of 1000 individuals, and the top 5 to crossover. We run the genetic algorithm with 500 cycles maximum.
Note that in this case the population are programs initially random until take the correct shape.

An evaluation function is provided in the run method as well, and looks like this:

The evaluation function receives a CPU object, to compute a test you need to set the initial parameters, run the program and set a scoring regarding the return value.

Related articles

• Pentest With Kali Linux
• Hacker Language
• Hacker News
• Pentest Devices
• Hacking
• Hacker News

Hacking PayPal's Express Checkout

Do you know what is happening in the background when you buy something in an online shop using PayPal?

In this post we will tackle the following problems:

• How can PayPal's API be tested?
• How does PayPal's Express Checkout work? You can find the detailed report here.
• How can we debit more money than authorized?

How PayPal's API can be tested?

PayPal's Sandbox API

PayPal offers a feature called PayPal Sandbox Accounts, which mimics the production API. The basic idea is that a normal user/shop can test the API and make transactions without actually transferring money. This is the perfect tool for developers to test their API integration.

Access to all messages

The next question is how to get access to all messages. All browser-related messages can be inspected, intercepted, and modified via BurpSuite. The main problem here is how to get access to the server-to-server exchanged messages: the messages exchanged between PayPal and a shop. In order to solve this problem, we deployed our own shop. For this purpose we used Magento, which already has a PayPal integration.
Once we have our own controlled shop, we can enforce Magento to send all request through a proxy.
In the following picture you can see our setup.

Test suite for analyzing PayPal's API [1]

In order to capture the traffic between our Magento hhop and PayPal we proceeded as follows:

• We configured Magento to use a proxy running on localhost:8081.
• We connected the proxy port on the virtual machine with our local machine via SSH remote port forwarding by issuing the following command

    ssh -N -R 8081: localhost :8081 <IP of Magento shop>

• We configured BurpSuite running on our local machine to listen on Port 8081 for incoming requests.

Now, we were able to see the entire traffic.
Please note that we uses our own, custom Magento shop in order to be able to test Paypal's API.

PayPal's Express Checkout

An overview of the checkout procedure is depicted in the following:

PayPal's Express Checkout [2]

Step 1: Magento tells the PayPal API where to redirect the user after authorizing the transaction via the parameter RETURNURL and requests a token for this transaction.
Step 2: The PayPal API provides Magento with the token.
Step 3: Magento redirects the user to PayPal's website. The redirect contains the token from the previous step.
Step 4:  The user authorizes the transaction. As a result, he will be redirected back to Magento (RETURNURL) with the token.
Step 5: Magento issues a request to the PayPal API to get the transaction details.

Step 6: Magento signals the PayPal API to execute the transaction.

Step 7: Magento serves the success page.

A more detailed view of the protocol and all parameters is shown on page 16 in the full version. We will concentrate only on step 6 and the parameters relevant for the attack.

The Attack

The goal of the attack is to let a shop (in our case Magento) debit more money than authorized by the PayPal user. The core of the attack is Step 6 -- DoExpressCheckoutPayment. Let's get a deeper look at this message:

Magento can raise the authorized amount and debit more money from the user's account

• The shop sends the token, which was issued in the first step of the protocol and identifies uniquely the transaction through all steps. 
• The PayerID referring to the user that authorized the payment.
• The AMT defining the amount, which will be transferred.
• The API Credentials authenticating Magento on PayPal.
• The Version pointing to the release number of the API.

As one can imagine, the core problem we found was the change of the AMT parameter. This value can be freely chosen by the shop, despite the fact that the user has authorized a different amount.

We tested only the SandBox API, but refused to test the production API in order to avoid problems. We promptly contacted PayPal's security team and described the problem hoping that PayPal can and will test the production API against the attack.

The response of PayPal can be summarized as follows:

• We don't get any BugBounty since we only tested the Sanbox API. (Fair enough)
• In the Production API PayPal this flexibility is a wanted feature. Thus, PayPal allows a merchant to charge for shipping and/or other expenses different amounts. Any malicious behavior can be detected by PayPal. In case of fraudulent charges the consumer are protected by the Buyer Protection policy.

... but the Sandbox API was nevertheless fixed.

Authors of this Post

Daniel Hirschberger
Vladislav Mladenov
Christian Mainka (@CheariX)



[1] BurpSuite Logo
[2] PayPal Express CheckoutRead more

• Hacking Page
• Pentest Vpn
• Pentestgeek
• Pentest As A Service
• Pentest Website
• Pentest Questions
• Pentest Gear

Ethical Hackers Platform: How To Install A bWAPP In Windows 2018

bWAPP, or a buggy web application, is a free and open source deliberately insecure web application. It helps security enthusiasts, developers and students to discover and to prevent web vulnerabilities. bWAPP prepares one to conduct successful penetration testing and ethical hacking projects.

What makes bWAPP so unique? Well, it has over 100 web vulnerabilities!
It covers all major known web bugs, including all risks from the OWASP Top 10 project.  bWAPP is for web application security-testing and educational purposes only.

Have fun with this free and open source project!
bWAPP is a PHP application that uses a MySQL database. It can be hosted on Linux/Windows with Apache/IIS and MySQL. It can also be installed with WAMP or XAMPP. Another possibility is to download the bee-box, a custom Linux VM pre-installed with bWAPP.

First of all you have need to install a local server over system that may be XAMPP, WAMP or LAMP. These servers are totally free of cost you can freely download from the internet. Mostly XAMPP is used because it has more functionalities than others on the other hand WAMP is also a simple platform for PHP while, LAMP is used over the Linux distributions. After downloading any one of them you have need to install that first after that you'll be able to configure bWAPP over your system.

Why we use the software application for configuring this bWAPP? As we know PHP is a server side language and there must be a server to read the PHP script. Without using any server we can't do programming with PHP. If you have a little piece of code of PHP you must install a server in your system for running that PHP script.