Web applications have been created to perform practically every useful function one could possibly implement online. Examples of web application functions that have risen to prominence in recent years include:
■■ Shopping (Amazon)
■■ Social networking (MySpace)
■■ Banking (Citibank)
■■ Web search (Google)
■■ Auctions (eBay)
■■ Gambling (Betfair)
■■ Web logs (Blogger)
■■ Web mail (Hotmail)
■■ Interactive information (Wikipedia)
In addition to the public Internet, web applications have been widely adopted inside organizations to perform key business functions, including accessing HR services and managing company resources. They are also frequently used to provide an administrative interface to hardware devices such as printers, and other software such as web servers and intrusion detection systems.
Numerous applications that predated the rise of web applications have been migrated to this technology. Business applications like enterprise resource planning (ERP) software, which were previously accessed using a proprietary thick-client application, can now be accessed using a web browser. Software services such as email, which originally required a separate email client, can now be accessed via web interfaces like Outlook Web Access.
This trend is continuing as traditional desktop office applications such as word processors and spreadsheets are migrated to web applications, through services like Google Apps and Microsoft Office Live. The time is fast approaching when the only client software that most computer users will need is a web browser. A hugely diverse range of functions will have been implemented using a shared set of protocols and technologies, and in so doing will have inherited a distinctive range of common security vulnerabilities.