Melissa and Love Letter made use of the trust that exists between friends or colleagues. Imagine receiving an 38 from a friend who asks you to open it. This is what happens with Melissa and several other similar email 39 . Upon running, such worms usually proceed to send themselves out to email addresses from the victim’ s address book ,previous emails, web pages 40 .
As administrators seek to block dangerous email attachments through the recognition of well- known 41 , 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 42 access to your network. 城域网中的MAC与OSI参考模型 层相对应。