Thursday

How The Web Really Works ?

So what happens for real when you just want to get to the FACEBOOK website ?

Assuming you are already connected to the internet , Here are the steps that occur in order
How web Work steps
  • You Open Your Browser.
  • You type in the URL(website name).
  • Website name saved in History Cache on the Hard disk.
  • Your computer looks up the name of the address to your default DNS server to find the IP address.
  • Your Computer connects to the server at the IP address provided ate the default web port of 80 TCP if you used “HTTP://” or 443 TCP if you used “ HTTPS://” at the front of the web server name.(‘HTTPS’ steps not follow in this example )
  • Your computer requests the page or directory you specified with the default often being “index.htm” if you don’t specify anything.But the server decide its default and not your browser.
  • The pages are stored in a cache on your hardisk. Even if you tell it to store the information in memory(RAM), there is a good chance it will end up somewhere on your disk either in a PAGEFILE or in a SWAPFILE.
  • The browser nearly instantaneously shows you what it has stored. Again, there is a difference between “perceived speed” and “actual speed” of your web surfing which is actually the difference between ho fast something is downloaded(actual) and how fast your browser and graphics card can render the page and graphics and show them to you.just because you didn’t see it doesn’t mean it didn’t end up in your browser cache.

Tuesday

Secure Computer: Scripting Languages

Secure Computer: Scripting Languages

Scripting Languages


Secure Computer: Scripting Languages

Many scripting languages have been used to develop applications that allow businesses to bring their products or services to the web. This is Great but it also creates a new avenue of attack for hackers.

The majority of web application vulnerabilities come not from bugs int he chosen language but in the methods and procedures used to develop the web application as well as hot the web server was configured.

suppose " if a form requests a zip code and the user enters "ABCDE" ,the application may fail if the developer did not properly validate incoming form data. several languages can be used for creating web applications, including CGI's, PHP and ASP.


  • CGI( Common Gateway Interface) : A standard way for a web server to pass a web user's request to an application program and to receive data back to forward to the user. CGI is part of the web's hypertext transfer protocol(HTTP). The most popular CGI application are : C,C++,JAVA and PERL.

  • PHP : PHP is an open source server side scripting language where the script is embedded within a  web page along with its HTML> before page is sent to a user, the web server calls PHP to interpret and perform any operations called for in the PHP script. whereas HTML displays static content, PHP allows the developer to build pages that present the user with dynamic, customized content based on user input. File name with the suffix "PHP".

  • ASP(Active Server Pages) : Web pages that have an .asp active server pages (ASP), are database drive dynamically created web page with a .ASP extension. They utilize ActiveX scripting usually VB Script or Jscript code. When browser requests an ASP, The web server generates a page with HTML code and immediately sends it back to the browser in this way they allow web users to view real time data, but they are more vulnerable to security problems.


Secure Computer: Honeypots

Secure Computer: Honeypots

Honeypots

A Honeypot is a computer system,network,or virtual machine that serves no other purpose than to lure in hackers.


In a honeypot, there are no authorized users, no real data is stored in the system, no real work is Performed on it, so every access, every attempt to use it, can be identified as unauthorized. Instead of sifting through logs to identify intrusions, the system administrator knows  that every access is an intrusion, so a large part of the work is already done.




Thursday

Secure Computer: Touchscreens Type

Secure Computer: Touchscreens Type

Secure Computer: Touchscreens Type

Touchscreens Type

Touchscreens enable users to interact with the visual display.There are three types of
touchscreen technology:

n Resistive—Two resistive material layers sit on top of a glass screen.When a finger,
n Capacitive—A charged material layer is overlaid on a glass screen.When a finger or
any conductive object touches the layer, some charge is drawn off, changing the
capacitance, which is measured to determine the location of the touch. Capacitive
touchscreens allow as much as 90 percent of the light through, although accuracy
can be less than resistive.

n Surface Acoustic Wave—This uses a more advanced method that sends and receives
ultrasonic waves.When a finger or any object touches the screen, the waves are absorbed.
The waves are measured to determine the location of the touch. It is the
most durable solution, but more suitable for large-scale screens such as automatic
bank tellers.
stylus, or any object applies pressure, the two layers touch together and the location
of the touch can be determined. Resistive touchscreens are cost-effective, but
only 75 percent of the light shows through, and until recently, multitouch was not
possible.

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