XSS (cross site scripting attack) for security interview

1、XSS principle : Developers did not do a good job of filtering , As a result, we can close the tag and insert and execute malicious JS Code

2、xss Type classification

DOM type ： from DOM The document is parsed

reflective ： Plug and play , Not stored in the database

Storage type ： Stored in the database , Cause persistent attacks

3、 frequently-used JS function

document.cookie()： Pop up the browser of the current web address cookie

console.log('xss')： Log output at the console

4、 Way around

4.1. Change case :<SCript>

4.2. Code bypass （html Entity encoding 、 Decimal hexadecimal octal encoding 、unicode code ）、

4.3. Turn off the tag ： Use the greater than sign > Closing the tag makes xss take effect

4.4. Double write and forgive ：<scr<script>ipt>

4.5. You can use spaces . Line break ,tab Key or /**/,/*!a*/, Bypass keyword detection in the form of

4.6. use / Instead of spaces
4.7. Use inverted quotation marks instead of parentheses 、 Double quotes
4.8. use throw Replace brackets
4.9. use html Entity encoding : Instead of a colon
4.10. use jsfuck Encoding bypasses most character filtering

5、 Scan tool

xsstrick

6、XSS Fishing platform

kali Tools ：BEEF

Free platform ：https://xss.pt/

Phishing statement ：<img src=https://xss.pt/hook.js>

7、xss defense

7.1、 Filter sensitive characters , for example ：aler()、<script>、onerror

7.2、 increase httponly： Front end execution is prohibited JS Code