What is the background of XSS attacks and what are the hazards of XSS attacks?

1. Phishing, including stealing all kinds of users;

2. Steal user cookie information, so as to obtain user privacy information, or use the user's identity to further perform operations on **;

3. Hijacking user (browser) sessions to perform arbitrary operations, such as making illegal transfers, forcibly publishing logs, sending emails, etc.;

4. Forced pop-up of advertising pages, swiping traffic, etc.;

5. Malicious operations such as arbitrarily tampering with page information, deleting articles, etc.;

6. Carry out a large number of client-side attacks, such as DDoS attacks;

7. Obtain client information, such as the user's browsing history, real IP, open port, etc.;

8. Control the victim's machine to launch attacks on other **;

9. Combined with other vulnerabilities, such as CSRF vulnerabilities, to carry out further evil;

10. Enhance user permissions, including further infiltration**;

11. Spread cross-site scripting worms, etc.

With the ability to inject ** into the resulting web pages, you can have as serious a threat as you can think of. Attackers can use XSS exploits to steal cookies, hijack accounts, execute ActiveX, execute Flash content, force you into software, or take action on hard drives and data.

This is possible as long as you click on some URLs. How many times a day do you click on a URL of a trusted email message from a message board or newsgroup when reading it?

Phishing attacks often exploit XSS vulnerabilities to dress up as legitimate sites. You can see a lot of this, such as your bank sending you an email informing you that some changes have been made to your account and tricking you to click on certain hyperlinks. If you look closely at these URLs, they may actually exploit a vulnerability present in the bank**, in a form similar to the "redirect" parameter that is exploited here to execute the attack.

Once an administrator opens the URL, they can perform many malicious actions, such as stealing his (or her) credentials.

XSS (Cross-Site Scripting Attack) is a common web application security vulnerability in which an attacker injects a malicious script into the victim's web page, causing the victim's browser to execute the script, so as to obtain sensitive information of the victim, or perform some bad behaviors, such as stealing cookies, recording user input, etc.

There are two main types of XSS attacks: reflective XSS and storage XSS. Reflective XSS means that an attacker injects a malicious script into a URL, and when the user clicks the URL, the server returns the URL to the user's browser as a parameter, resulting in the execution of the malicious script.

In the case of storage-based XSS, the attacker injects a malicious script into the database, and when the user browses the malicious script, the malicious script will be returned to the user's browser for execution.

In order to prevent XSS attacks, developers need to filter and verify the data entered by users, especially sensitive information entered by users, such as passwords, banks, etc. At the same time, it is also necessary to use secure programming techniques, such as using the httponly attribute to prevent cookies from being stolen, and using the Content Security Policy (CSP) to restrict the loading of external resources, so as to effectively prevent XSS attacks.

XSS is also known as CSS

crosssite

script)

Cross-site scripting attacks. It refers to the malicious attacker inserting malicious HTML** into the web page, and when the user browses the page, the HTML** embedded in the web will be executed, so as to achieve the special purpose of the malicious user. XSS is a passive attack, because it is passive and difficult to use, so many people often call it harmful.

XSS attacks usually refer to hackers getting through"HTML injection"An attack that tamperes with a web page and inserts a malicious script to take control of the user's browser while they browse the web.

Let's construct a backup cross-site statement as follows:

Or construct a cross-site statement and use an iframe to open a 0 size.

When the administrator opens it, it will automatically back up a shellFrom the above example, we can know that how to spoof management opening is a very important step, for spoofing opening, in addition to social engineering, we can combine other techniques, such as SQL injectionWhen we infiltrate a **, the master MSSQL injection vulnerability, the authority is public, at this time we use update to construct a cross-site statement, such as using an iframe to open a backup above to get the shell cross-site statement, etc., similarly, we can use other cross-site vulnerabilities of QQ and so on in social engineering.

Always for deception is also an art, how to use it, everyone use their imagination!

A good deception is also an art, both in life and in the network. It is inevitable that there are some things in life that cannot be told the truth, and at this time, it is up to the art of deception to adopt appropriate methods to make our falsehoods be told as the truth.

XSS attacks, also known as cross-site scripting, focus not on cross-site scripting, but on script execution. XSS is a computer security vulnerability that often appears in web applications and is caused by the web application's insufficient filtering of the user's input, which allows malicious web users to implant ** into pages made available to other users.

Here's a detailed introduction to learn about it.

Defending against XSS attacks requires the following principles:

When inserting untrusted data between HTML tags, HTML Entity encoding is used on that data.

When inserting untrusted data into HTML attributes, encode the HTML attributes.

When untrusted data is inserted into the script, the data is script-encoded.

When inserting untrusted data into the style attribute, CSS encode the data.

When inserting trusted data into the HTML URL, the data is URL encoded.

When using rich text, the XSS rule engine is used for encoding filtering.

XSS attacks, known as Cross Site Scripting, are not confused with the abbreviation Cascading Style Sheets (CSS), which is a type of computer security that is often used in web applications.