Protecting your Data and System from Hackers and Attackers Online

Knowing File Extension and The File Format Before and After Download is Import
Knowing the file extension of a file is very important. In fact as a user you must know the file format of any document you are operating on. Especially when handling files downloaded from the internet you must be sure the file is safe for use. Some hackers and attackers on the world wide web take advantage of this to destroy peoples computer or even to collect sensitive data such as bank account details, passwords etc. from a user’s computer when available. So knowing the file format that you are downloading is very important. When you download a file from the internet do not open the file unless you have properly checked and confirmed the file format to be good enough for opening.

How to check file format

To check the file format of any file you have to do the following

1. Locate the file. You can search for the file by typing the file name on the system search box.
2. Having located the file, next is to take your mouse over the file and wait some seconds small box will pop up showing some information about the file. See image 1 below.

 

Image 1

 

The “Type: Adobe Photoshop Image 13” tells us that this file will be opened with adobe Photoshop software if double-clicked.

That is enough to tell you what application software on your computer will be used in opening the file by default.

The “Size: 1.28MB” tells you the size of the file and the “Date modified: 10/28/2016 10:41 PM” tells you the date the file was modified last. You can get more information about the file as you will see in a moment

 

The next image 2 below tells us same thing. But this time it gives the “Type: JPEG image” this means the file is a JPEG image file. If double – clicked, the system will not launch a third party application to open it but will use its’ image viewer application to do that.

Image 2

 

3. When the information provided is not enough you can right – click on the file to bring up a menu as shown in image 3 below.
4. Click the “Properties” at the bottom of the menu and more properties will be displayed.

The property box has four panels. The “General” tab has “Type of file” which tells you two things

1. The file format. i.e. “JPEG image” – in this case. And most importantly, it also tells you
2. The file extension of the file which is the “(.jpg)”

Both are given as “Type of file: JPEG image (.jpg)”

The file extension is what you need to not mistake. For instance when viewing a file name, it is usually written with the file extension prepended to it. That is a JPEG image file named “flower” could be listed as “flower.jpg” on the internet page where you download images. Now this is where some hackers or attackers could take advantage of the user’s ignorance to harm the user. If the file is not an image file, the attacker could name the file and include the “.jpg” file extension as the name or any other friendly file extension. For instance, say the attacker has created an application that collects a user form input data and he names the application file “goodApp.jpg.exe”. Some user who downloaded the file and does not know what the file is will think it is an image file because after downloading and viewed on the file explorer the file will be displayed thus “goodApp.jpg” and the “.exe” suffix would be hidden. There the attacker has gotten the user. So a good thing to do to avoid this is to ignore the suffix seen on the image vied through the file explorer. But the user should endeavor to check the correct file extension instead of the suffix displayed to be sure of the correct file format.

NOTE: This is why the file in the image 3 and image 4 has the file name as “Softance.png” – suggesting it is PNG Format File – when viewed on the file explorer. But when checked properly you know it’s a JPEG file

Image 3

 

Image 4