The security journey of web development

A look at web security

Security issues 'very common' and can harm

user
company
Programmer (sacrifice to heaven)

Web security from two perspectives

If you are a hacker - attack
If you are a developer - Defense

Attack

Cross-Site Scripting(XXS)

Features

Often difficult to detect from the UI (executing scripts secretly)
Steal user information (cookie/token)
Draw UI (such as pop-up window) to trick users into clicking/filling in the form

demo

Srored XSS (database attack)

Malicious scripts are stored in the database
Access the page → read data—under attack
The most harmful, visible to all users

Reflected XSS (database attack)

No database involved
Attack from URL

Mutation-based XSS (database attack)

Utilizes the browser's ability to render DOM (unique optimization)
Different browsers will have differences (attack based on browser)

Cross-site request forgery(CSRF)

Without the user’s knowledge
Taking advantage of user permissions (cookies)
Construct specified HTTP requests to steal or modify user sensitive information

demo

GET

SQL Injection

demo

Read request fields
Directly concatenate SQL statements in the form of strings

Injection is more than just SQL

CLI
os command
Server-Side Request Forgery (SSRF), server-side forged request
Strictly speaking, SSRF is not injection, but the principle is similar

SSRF

Request [user-defined] callback URL
The web server usually has intranet access rights

Denial of Service(DoS)

Through a certain method (constructing specific requests), server resources are significantly consumed, leaving no time to respond to more requests, resulting in request squeeze, and then an avalanche effect.

Interlude: Regular Expressions - Greedy Mode

Distributed DoS(DDoS)

In a short period of time, due to the request traffic from a large number of zombie devices, the server cannot complete all requests in time, resulting in a pile-up of requests, resulting in an avalanche effect and the inability to respond to new requests.