Melissa and LoveLetter made use of the trust that exists between friends or colleagues.Imagine receiving an （） from a friend who asks you to open it. This is what happens with Melissa and several other similar email （） . Upon running, such worms usually proceed to send themselves out to email addresses from the victim’s address book, previous emails, web pages （） . As administrators seek to block dangerous email attachments through the recognition of well-known （） , virus writers use other extensions to circumvent such protection.Executable (.exe) files are renamed to .bat and .cmd plus a whole list of other extensions and will still run and successfully infect target users. Frequently, hackers try to penetrate networks by sending an attachment that looks like a flash movie, which, while displaying some cute animation, simultaneously runs commands in the background to steal your passwords and give the （） access to your network.
web pages （） .
A．memory
B．caches
C．ports
D．registers
