tailieunhanh - snort 2.1 intrusion detection second edition phần 4

Tại dấu nhắc, gõ và nhấn Enter. 9. Lệnh thực hiện cũng sẽ mang lại cho bạn trở lại một dấu nhắc khi đã hoàn thành công việc của mình. Một lần nữa, bạn cần phải kiểm tra đầu ra mà làm cho hiển thị trên màn hình để xác minh rằng các hoạt động là rắc rối. Tại dấu nhắc, gõ thực hiện cài đặt và nhấn Enter. 10. | 198 Chapter 5 Playing by the Rules Simpo PDF Merge and Split Unregistered Version - http snort which rule should activate this rule and a count rule option that specifies how many packets Snort will process before deactivating the dymanic rule. Generally dynamic rules are used to log additional information on a session. This functionality is better expressed with aa tag option described in chapter following example logs the next 5 bytes on port 143 after the first rule is fired activate tcp any any - any 143 content E8C0FFFFFF bin activates 1 dynamic tcp any any - any 143 activated_by 1 count 5 OI nk Activate and Dynamic rules are being phased out in favor of tagging. In future versions of snort activate dynamic will be completely replaced by improved tagging functionality. For information on tagging read Chapter 4. Rule Options First let it be known that Snort rules do not require the body field to be complete rule definitions. The body of the rule is an excellent addition that extends the breadth of rule definition beyond simply logging or alerting based on packet source and destination. With this said we don t want to disregard the importance of the rule body because it can be considered the meat and potatoes for rules identifying complex attack sequences. The body format is broken down into sections separated by semicolons. Each section defines an option trailed by the desired option value. The rule options that can be included range from protocol specifics and fielding including IP ICMP and TCP. Other applicable options include messages that print out as reference points for the system administrator keywords to search on Snort IDs to use as a filing system for Snort rules and case-insensitivity options. The rule options are separated by semicolons within the main body of the Snort rule alert tcp any any - any 12345 msg Test Message As you can see the rule s body in bold is confined by the parentheses. In this case the body of the message