So logout is another important function in applications as a login mechanism log out, you should also
be done securely.
But sometimes the application doesn't log out the user properly.
And of course, this causes some serious privacy problems.
There may be hundreds of ways to implement such an insecure logout function.
So let's just have a look at one of them from BW.
OK, so go to Caleigh and log in to be Web.
And from the drop down menu above opened the logout management under broken authentication.
OK, so this is a sample authenticated page, and the default level is low.
Now view the page source to get some interesting information if, of course, the source has it.
And there's nothing here.
So when the link is clicked, JavaScript confirmation dialogue will appear and then the location will
redirect us to a new page.
B.A. underscore logout, underscore one.
OK, so now open berp.
And activate interception.
I'm going to rearrange my brother here for a better view.
All right, enabling foxy proxy to send traffic to burb.
And now I'm going to click here to logout.
OK?
And burb capture the lock out request.
So let's forward the request.
And we get a three oh two redirection response, hmm, so it redirects us to another page with a location
header.
What is it, log in.
So that means that the application log out.
Sends us to the login page, doesn't log is out.
So this is a general logout mechanism example.
And I'm going to forward the next messages as well.
And I logged out.
So the login page opened in the browser, but do we really log out?
OK, so now move on to the back button in the toolbar, right?
Click.
And you will see pages that we've previously visited and cashed.
As you can see, the authenticated page that we visited is right there.
So if we go back, the page will be displayed and I forgot the purpose interception mode.
So go forward.
Disable interception, disable foxe proxy also.
And open the page again, as we think it should.
So now let's visit some other pages.
And as you can see, we're still logged in.
So even for the medium and high level, the application really blog out the user.
But there are a few differences in the code.
So now select medium.
And I'm going to click here to log out, OK, so I logged out.
But when I pressed the back, but nothing happens.
This means that the application did indeed Lagny out.
And the same thing happens when I choose the high level.
OK, so let's let's go to the code and have a look, see what's happening.
Now, I previously downloaded the VoIP application of Cali because sometimes I want to show you the
code as well, so I'm going to open the underscore logout, underscore one.
And scroll down to see the actual section of logout.
I yeah, so it works based on the cookie levels, if the level is low, it does nothing and that's why
we can see the page by pressing the back button.
And if the level is medium, it just destroys the session.
Now, for locking out, it may be enough.
But it isn't really secure, is it, because the session related values are still present in the session
variable in memory.
So this variable also needs to be assigned a null or empty value.
And that is done in the high level, as you can see here.
So this bug is directly caused by an insecure logout mechanism.
But we'll be talking about session problems in the next.
I want to go on with a couple of other problems.