tailieunhanh - e mail virus protection handbook phần 4

Sử dụng mã hóa làm cho nó khó khăn cho người sử dụng trái phép để đọc hoặc làm xáo trộn e-mail của bạn. Có ba loạiTrên nền tảng Windows 9x, điều này được thực hiện bằng cách đặt dòng lệnh sau đây trong | 128 Chapter 4 Web-based Mail Issues POST config login 5o0hílhv03 7e5 HTTP image gif image jpeg. image pjeg application .Referer http config mail .intl us .lg application gzip Mozilla compatible MSIE Windows 98 DigExt . Host Keep- .src ym .last promo .intl us bypass . partner .chkP Y .done login marfino passwd password. The last portion of this packet clearly states the user name and password earlier mentioned as login marfino and password password. Once a malicous user obtains this information he or she can then log into your Web e-mail server with impunity. Most hackers who have been able to do this simply read the e-mail messages rather than deleting them or conducting noticeable mischief. This is because most hackers are interested in gaining information over a long period of time if a hacker were to delete an e-mail message he or she would leave signs of tampering. It is likely that many e-mail accounts are actually compromised the victim simply doesn t know about it. Case Study Some of America Online configurations are subject to sniffing attacks. A sniffer is a program that monitors and analyzes network traffic. It is designed to detect bottlenecks and problems on the network. Using this information a network manager can keep traffic flowing efficiently. There are many different commercial sniffing products available on the market such Network Associate s Sniffer Basic or the UNIX tool TCPdump. As you might remember a sniffer can also be used to capture data being transmitted on a network much like wire tapping a phone. A sniffing attack is when a sniffer is used to capture the data in transit data such as passwords during login and e-mails once they are sent. The following figures illustrate the use of Network Associate s Sniffer Basic to monitor an e-mail