Book Web Exploitation

Transcript

1. Web Exploitation
   How to become an online spider
   Computer Networks
   Modern life would be very different without computer networks. These generally
   comprise of multiple computers (‘​nodes’​), that are connected together to share data
   and resources. The most popular Computer Network is ​The Internet​, which specifically
   connects computers that use the Internet Protocol or ​‘IP’​.
   How does the Internet work?
   Completely new and need to know the basics? ​Here​ is a great article that explains the
   very basic architecture of the internet and how data is transmitted.
   Website Basics
   Now information on the Internet is segregated by ​websites​. They are a collection of
   web pages and are referred to by a domain name (like google.com, facebook.com).
   Each web page is referred to by its URL or Uniform Resource Locator.
   1. What is a web page and website?
   A website is a collection of web pages. So website would be like a house and
   each webpage would be a room inside the house.
   2. Breakdown of a URL:
   https://developer.mozilla.org/en-US/docs/Learn/Common_questions/What_is_
   a_URL
   3. Querying:
   https://en.wikipedia.org/wiki/Query_string
   4. Different parts of a website and how to mess with it (HTML, CSS, JS, Backend)
   a. HTML breakdown
   Here is a basic tutorial on HTML:
   https://www.w3schools.com/html/html_basic.asp
   

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2. b. CSS breakdown
   Here is a basic tutorial on CSS:
   https://www.w3schools.com/css/css_intro.asp
   5. Viewing source
   By right clicking on Google Chrome or Firefox you can select the option “View
   Page Source” to see the code that the website is running on your computer. It
   allows you to see the HTML and CSS that is running on the website and it will
   also let you see the Javascript scripts running on your computer. The best part
   is, that you can edit the HTML directly and see it affect the website, so it lets
   you modify the website as you desire. You can also select “Inspect Element” to
   see the code that is running in a specific part of a website.
   JS Breakdown
   1. Why we need it?
   Javascript is used because it allows us to add interactivity between the user and
   the website. Javascript allows the user to interact with the website and have the
   website respond.
   2. Basics - Editing elements HTML
   https://www.w3schools.com/js/js_htmldom_html.asp
   HTTP breakdown
   1. What is HTTP?
   It provides a standardized way for computers to communicate with each other
   over the internet. HTTP is a communication protocol, that is used to deliver
   data (HTML files, image files, query results, etc.) over the internet. HTTP
   dictates how data is sent between clients (you) and servers.
   2. GET and POST request
   https://www.w3schools.com/tags/ref_httpmethods.asp
   3. Basic Architecture
   

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3. 4. Basic idea of a proxy
   A proxy server is a computer on the web that redirects your web browsing
   activity. When you try to access any website, your Internet Service Provider
   (ISP) makes the request for you and gives the website your IP address. So when
   you use a proxy, your request goes from your ISP to the proxy server to the
   website you want to go to. This way allows you to mask your IP address as
   another address so that the websites you access don’t know who you are.
   Database breakdown
   1. What they are and why they are useful
   A database is a collection of information that is organized so that it can be easily
   accessed, managed and updated. Databases can quickly query data and
   add/delete data instantly. They are used to hold every kind of data.
   2. SQL and others
   

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4. SQL is Structured Query Language (SQL), a programming language used for
   managing relational databases. Relational databases are tabular database in
   which data is defined so that it can be reorganized and accessed in a number of
   different ways. Relational databases are easy to extend, and a new data category
   can be added after the original database creation without requiring that you
   modify all the existing applications. Relational databases are made up of a set of
   tables with data that fits into a predefined category. Each table has at least one
   data category in a column, and each row has a certain data instance for the
   categories which are defined in the columns.
   3. How they integrate into sites
   Databases are integrated into websites because they are the most optimal way
   to display/store data. User information like passwords are stored using
   databases. Databases also allow for quickly modifying the data displayed on the
   website. So if someone wants to update information on a website instead of
   modifying the HTML on the website, they can just change the data on the
   database that is displayed on the website.
   4. Basic SQL syntax
   a. SELECT
   Extracts data
   b. ORDER BY
   Orders the results gotten from SELECT in a specific manner. For
   example, if one has a table of countries and their populations. One can
   select the countries starting with the letter R and then order them by
   their population.
   c. JOIN
   Joins data from two tables depending on a certain characteristic on the
   table. So if a theres two table one with customer IDs and their addresses
   and another table with customer IDs and their purchases. You can join
   both tables so that the customer addresses match their purchases.
   d. DELETE, INSERT
   Allows you to delete data or add new data to a table.
   e. AND,OR
   Allows you to modify queries so that they return information depending
   on multiple categories.
   f. MIN,MAX
   They return the smallest or largest value of a query.
   

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5. Injections
   1. How to perform a basic SQL injection and how its possible
   SQL Injection (SQLi) refers to an injection attack where an attacker can execute
   whatever SQL commands they want that control a web application’s database
   server. Websites use the information you give them to query SQL, for example
   when logging onto a website, the website will query your username and
   password to see if you are an authorized user. A SQL injection would allow the
   user to supply their own SQL code and run it on the website.
   2. How to safeguard against SQL injection(safely accept user input)
   a. Prepared statements
   Prepared statements are a way to separate code and user supplied input.
   It’s the most common way to avoid attackers from attempting to run SQL
   code by supplying it as input. Prepared statements will not execute the
   SQL code and will treat the input as a query and not as code.
   3. How to perform a PHP object injection
   https://www.tarlogic.com/en/blog/how-php-object-injection-works-php-objec
   t-injection/
   

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6. Glossary
   1. ‘IP’ or ‘Internet Protocol’​: A set of rules that govern how data is transmitted over
   The Internet.
   2. IP Address​: A unique name given to every computer connected to the internet. It
   looks like ‘a.b.c.d’ where each of a,b,c,d is a number between 0 and 255.
   3. Packet​: In terms of the Internet, if the amount of data being transmitted is too
   large, we break it down into smaller chunks, called packets.
   4. Port Number​: In Networking, a port is an endpoint of the communication and
   the port number is the specific number associate with a particular port.
   5. Domain Name Service (DNS)​ : A database which stores the IP address of each
   website and its ​domain name​ (like google.com).
   6. Client: ​These are usually computers of users looking to access web pages or
   search engines. These are usually the ones looking to get a particular service.
   7. Server:​ These are computers that store web pages, services or applications.
   They are usually the ones providing the service.
   8. Webpage: ​A single hypertext document that is connected to the World Wide
   Web.
   9. Website​: A collection of related web pages usually connected to one common
   domain name.
   

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