ASP. NET development practice course series-spam for Web Application Security Defense)

Spam Overview
Spam was initially a brand of canned meat. It is a specially processed mixed meat of "specially processed assorted meat ".
In the Internet era, spam is used to refer to spam (information) distributed everywhere on the Internet)
Spam refers to malicious or massive repetitive emails that people do not want to see without authorization. He brings threats and difficulties to the Internet and Internet service providers.

Disturbing people. Spam is used to refer to spams distributed everywhere on the Internet.

Main spam forms and hazards
Send spam messages such as drugs, pornography, fake messages, and malicious advertisements to others by sending mass emails.
Contains virusesProgram.
Contains hidden text and repeated keywords.
A large number of duplicate messages do not contain the same or empty content.
A large amount of illegal content

Spam principles
Collect a large number of email addresses and send them to a group
A large number of Malicious spam messages are posted to message boards or blog comments.
Use special programs to impersonate a viewer to instantly submit a large amount of junk data to the website
The OCR program automatically identifies simple verification code images and continues to submit a large amount of junk data information.
Illegal content is submitted to a website system that has not been filtered or is not strictly filtered.
Uses text styles to visually hide spam messages, deceiving search engines and viewers

Main defense methods of Spam
Set the spam filter function
Reduce Direct Email exposure
Use the full selection function of the browser as appropriate
Create an HTML Filter System
Prohibit users from submitting data repeatedly in a short time through technology
Use the verification code function that is not easy to be recognized by the OCR System
Using httpmodule or other means, the Website Cannot submit illegal content globally.
Block Some IP addresses to access website systems through firewall and other technical means
Appropriate manual content review mechanism