单选题
Melissa and Love Letter made use of the trust that exists
between friends or colleagues. Imagine receiving an{{U}} {{U}} 38
{{/U}} {{/U}}from a friend who asks you to open it. This is what happens with
Melissa and several other similar email{{U}} {{U}} 39 {{/U}}
{{/U}}. Upon running, such worms usually proceed to send themselves out to email
addresses from the victim' s address book ,previous emails, web pages{{U}}
{{U}} 40 {{/U}} {{/U}}. As administrators seek to
block dangerous email attachments through the recognition of well-
known{{U}} {{U}} 41 {{/U}} {{/U}}, virus writers use other
extensions to circumvent such protection. Executable (.exe) files are renamed to
. bat and . cnd 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{{U}} {{U}} 42 {{/U}} {{/U}}access to
your network.