Shulou(Shulou.com)05/31 Report--

This article mainly introduces how to prevent XSS loopholes, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let the editor take you to understand it.

XSS attacks can be used to gain access to privileged information, and this article is about how to deal with them. The U.S. Department of Homeland Security (Department of Homeland Security) is warning federal agencies against a particularly aggressive form of cyber attack-cross-site scripting attacks (XSS).

The U.S. Department of Homeland Security warned:

"this attack allows attackers to enter the site pretending to be victims, and these vulnerabilities may allow attackers not only to steal cookie, but also to record keystrokes, capture screenshots, discover and collect network information, and remotely access and control the victim's device."

Barracuda Networks senior security researcher Jonathan Tanner (Jonathan Tanner) said:

"given the high value of their digital assets, federal agencies may be particularly at risk. with federal agencies, access to privileged information and privileged infrastructure is very profitable for attackers. Whether it is attacking the voting system or simply disrupting government affairs, these can be very strong motivations for attack."

What is a cross-site scripting attack?

Cross-site scripting attacks involve malicious participants inserting secret code into the site to target the victim. "there are several ways to attack, but basically the attacker injects malicious script into the website database to allow users browsing the site's browser to execute the script," said Adam Meyers, senior vice president of CrowdStrike intelligence.

As a client-side code injection attack, XSS allows attackers to perform malicious actions through the victim's web browser. Government agencies' web pages or web applications are essentially tools for spreading malicious scripts. When the victim visits the web page or web application, the code is executed.

How do cross-site scripting attacks occur?

Although there are several forms of XSS attacks, the result of all attacks is essentially the same: execute malicious code in the user's browser.

Typically, when a user interacts with a web application or Web site, data is sent back and forth between the client and the Web site or application front end. Most of this may be harmless data that can be browsed at will, or there may be some pages or inputs in the application that collect data from the user.

XSS uses these inputs to insert its malicious instructions. Take a simple blog or forum, for example. Generally speaking, the author will post a blog post on the website, and other users can comment on it. These comments are collected through a free-form text box with a submit button.

In the background, the application is collecting data from these input fields: names, e-mail addresses, comments. What prevents people from putting something else in the text box and propagating it back to the web application? There's probably nothing. In this case, the site itself can be used to perform cross-site scripting attacks.

What is Cookie theft?

Cookie theft is a tool in the library of cross-site scripting attacks that uses information stored in the user's Web browser cache to identify users in a particular connection or session.

If the attacker can steal the user's cookie, then the attacker can impersonate the end user. In the XSS vulnerability, if the attacker can steal the user's cookie, he can become the user or impersonate the user. An attacker can take over the entire account by changing the user's password and changing the user's backup mailbox.

Such an attack may allow a malicious attacker to obtain a secret key to steal a user name and password. If the user has a government network management certificate, the potential harm may increase exponentially.

What is the difference between XSS attacks and cross-site request forgery attacks?

A cross-site request forgery attack is a variation of the XSS method that forces end users to perform unwanted operations. For example, an attacker may trick users of a web application into changing email addresses or transferring funds.

Using XSS, it attacks users, changing the content of the page or the way the page is rendered in the browser, to be exact, it takes advantage of the user's trust in the site.

In cross-site request forgery, it pretends to be a user to take advantage of the trust of the web server to the user. If the user authenticates the web page, the server knows that you are logged in. The attacker then uses the token to make a request on behalf of the user, usually without their knowledge, they can change anything that the user may change.

How to detect cross-site scripting attacks

XSS attacks are notoriously difficult to detect because browsers cannot distinguish between legal and illegal behavior.

Only after the attack, researcher Cai can scan the code for vulnerabilities to make sure nothing is missing. There are many free and paid resources that can do this to look for areas where these specific types of attacks or may be vulnerable to such attacks.

The Web application filtering tool also provides some protection, and when the server detects the payload of an attack, it is a good mechanism for detecting attacks in progress. The Web application filter will look for requests with a specific context that reflect XSS attacks. This can be attributed to anomaly detection, and researchers can also achieve it through a log product that integrates threat detection.

However, experts say that overall, the best way to defend against XSS attacks is prevention rather than detection.

Prevention skills of cross-site script

Make sure your browser is patched and that you exit the site after you have finished your work. This ensures that cookie is no longer valid, so please consider the website you visit carefully. Another good strategy is to use multiple browsers: one for trusted sites and the other for untrusted sites.

At a higher level, you can consider its development process and build security measures to protect applications and websites from such attacks. XSS is easy to prevent, but without security principles as the basis for development design, it will be ignored when security measures are used afterwards.

The easiest way is to install a filter to make it reasonable when the user adds input, such as the phone number should be the phone number and the date should be the date, not a Java script. Make sure that if your application asks for a name, the name should not be active and encode it before displaying it to the user. In this way, the attacker cannot launch an attack using plain text. However, such an advanced approach largely depends on the skill level of the developer.

Thank you for reading this article carefully. I hope the article "how to prevent XSS loopholes" shared by the editor will be helpful to everyone. At the same time, I also hope that you will support us and pay attention to the industry information channel. More related knowledge is waiting for you to learn!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.