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- Hello, and welcome to the Android
Security and Exploitation training series

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by Pentester Academy. My name is Aditya
and I am your course instructor for this

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entire training series. So this course is
being run on PentestersAcademy.com as well

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as securitytube-training.com is where you
get your certifications. So this

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particular video is about the Damn
Insecure and Vulnerable Application, or

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"DIVA" and we are checking out the "Input
Validation Issues - Part 2", right. So in

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the previous Input Validation Issue, it
was a classic case of a SQL injection

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vulnerability. Now in this case, if you
look at the application, or the "Input

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Validation Issues - Part 2", it asks you
to enter a URL, and that particular URL

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content will be displayed below, right. So
let's say if I enter "www.attify.com", it

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tries to open the attify.com website, but
it isn't able to, right, because there's a

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proxy server on the device or for some
other reason. Now, at the same time, you

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might wonder that since it is able to open
the websites using this embedded web view,

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will it be able to access the internal
files using the file protocol, right. So

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if we look at the "adb shell", and let's
say "/data/data/jakhar.aseem.diva", and we

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notice we have a file over here. So let's
try to read this file from this particular

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browser, or the embedded browser. So we'll
do "file:///data/data/jakhar.aseem.diva/"

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the file name, right. Let's just remove
the space from here and everything looks

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well and good.
And if we try to click on "view," it

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actually showed us the contents for this
particular file, right. So

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"aditya:aditya123" is stored over here and
this is what we get over here. Now, this

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is a really critical security issue
because an attacker can use this

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particular functionality to read the
internal files from the file system,

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right. So maybe it could be a simple
information as the temporary files, or it

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could be something as sensitive as a
cookie stored in one of the databases,

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right. So this is what you can do with
these kind of security issues with the

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input validation flaw. And also, you might
wonder that since you are able to read the

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local data storage, will you also be able
to read the external storage? Now, since

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the application has permissions to read
the external data storage, let's try to

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read a file stored on the SD card. And for
this example, let's try to simply read the

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"test.txt", which contains a string called
"secret". Let me just delete this and try

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to read the "/mnt/sdcard/test.txt" which
is a file stored on the external data. And

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it shows us the contents of this
particular file, right. So this is one of

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the examples of how an input validation
issue could lead to the data being stolen

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or the sensitive data being compromised.
And that is all for this particular video.

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So you might want to experiment with what
else you can do with the input validation

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issue as well.

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So thanks for watching the video, and if
you have any feedback or queries, feel

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free to reach out to me @adi1391 or you
can email me at adi@attify.com.

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See you in the next video.