Hi there,
An university has a Unix server with many terminal placed around it ( lab, library, canteen..) sothat students can access and use installed services, including Internet access.
The bookshop of that university have an online selling site. It enable students to acess book's categories via Internet, no choose necessary books, and to order a book, using credit card number to pay.

For example ,
A student Alice will do the following step to buy books:
1. Using a terminal to sign in to that server
2. She chooses a WebBrowser (Netscape, ie...) to acess to the site of the bookshop and choose books that she wants to buy.
3. She orders a book with her credit number via the Internet

Requirement:
1. Describe briefly 3 security threats in this scenario
2. For each threats, describe the methods to prevent