‫Instructor: Hi. Within this section
‫we are going to focus on cloud server security,
‫specifically Firebase security.
‫So Firebase is a cloud server backend system
‫provided by Google,
‫and it's commonly used in app development.
‫Whether it's an Android or iOS,
‫and also it's used in web development as well.
‫But there can be some vulnerabilities
‫if the Firebase security rules are not properly configured.
‫So within the section, we are going to focus on this issue.
‫And in order to simulate this in a real example,
‫I have written a Twitter app specifically for this course.
‫So I'm going to share this Twitter app with you via GitHub.
‫And you're going to see all the source codes.
‫And of course you're going to build this
‫on your own as well.
‫And you're going to follow me along.
‫We are going to take all of these codes
‫and embed it in our own project and make it run
‫as you are seeing right now, okay?
‫So these articles, I'm going to share them with you.
‫And also you're going to create a Firebase server.
‫You will create a Google account,
‫you will create a Firebase account.
‫You will learn how to connect Firebase with your project
‫and then do whatever you want to do with it.
‫Of course, if you are not an under a developer
‫you will still understand this course.
‫I will explain all these codes, what they do,
‫but of course it's not a development course,
‫so we are not going to write it from scratch.
‫We will be using these codes
‫that I have written for this course.
‫But you will see the basics,
‫you will understand what they do.
‫And again, as I said before,
‫we are going to create our own Firebase database
‫and connect it with our app as well.
‫So this is very commonly used in app development right now.
‫As you can see, this is our database
‫and there are some other modules regarding Firebase,
‫like storage, like authentication.
‫We're gonna see a couple of these other modules as well,
‫during our app-building phase.
‫And then after we build this app,
‫we are going to hack into it
‫and we are going to hack into database.
‫And then afterwards
‫we are going to see how to make it secure.
‫So over here, let me show you how this app works.
‫If you have
‫any account like this,
‫you can sign in with your account,
‫or if you don't have, you can create a new one.
‫And we are going to see how we can do that
‫with Firebase as well.
‫So Firebase has its own user module authentication module,
‫so we can create usernames and passwords
‫and we can save them in Firebase as well.
‫So as you can see, there is a Signup and Sign In button.
‫So if we have already an account
‫we can say Sign In and it'll sign us in
‫and we will see the tweets like this.
‫So this is very short for a tweet.
‫Maybe you can think this like an chat app or something,
‫but you get the idea.
‫For example, if I hit a tweet over here I can write a tweet.
‫So we have a 140 character limit here just like in Twitter.
‫Once I'm done with my tweet,
‫I can just hit the button,
‫it will add that tweet on the top of the list.
‫So I can see my own tweets.
‫I can see the other people's tweets as well.
‫So right now I'm connected with lars@gmail.com
‫and as you can see, we have james@gmail.com as well.
‫So we are seeing other people's tweets
‫and they're all saved in this database
‫under Tweets Collection,
‫and we'll see what a Collection is later on.
‫And as you can see, it works.
‫It's great.
‫But there is some kind of vulnerability in this app.
‫So we are going to see how to exploit it.
‫For example, I'm going to execute a comment over here
‫in which we can get all the data for this database.
‫And this is not coming,
‫this is not happening because I am the owner of this app.
‫You can write it anywhere from anywhere you want
‫and you will still get this data.
‫And you can even delete the data
‫after you get the data.
‫For example, I'm going to choose this tweet, okay.
‫I'm going to copy it
‫and I'm going to change the command over here,
‫and I'm going to paste it in.
‫And then I'm going to hit Enter
‫and it will delete the data from database.
‫So let me open the database and find that related documents.
‫So let's see, what was it, t's POB.
‫Let's find POB.
‫It will be around here.
‫And here you go, I believe it's there.
‫So when I hit Enter, it will just delete this, okay?
‫And you will see it in real time.
‫So I deleted it.
‫As you can see, it's removed from the Firebase database.
‫So of course you haven't understood anything
‫if you are not familiar with Firebase
‫or under a development.
‫But again, we are going to take care of that in the section.
‫So that's it, that's what we are going to do.
‫We are going to build a Twitter app
‫and then we are going to hack it,
‫and then we are going to learn how to fix this problem
‫so that no one can hack into our apps
‫if we are a developer.
‫So if you are ready,
‫let's get started within the next lecture.