Use tools and tests to prevent cross-site scripting attacks

| Cross-site scripting (XSS) attacks are one of the main attack methods today. They exploit Web site vulnerabilities and use browsers to steal cookies or perform financial transactions. Cross-site Scripting Vulnerabilities are common and require organizations to deploy well-developed security development lifecycles covering Threat modeling, scanning tools, and a large number of security awareness to achieve the best XSS protection and prevention. This article explains how cross-site scripting attacks are implemented and provides suggestions on how to protect enterprise Web applications from such attacks.

Cross-site Scripting: How to Implement XSS attacks?

Cross-site scripting (XSS) allows attackers to exploit Internet server vulnerabilities to send malicious code to other users. Attackers use cross-site scripting (XSS) attacks to inject malicious code into seemingly trustable links. After a user clicks a link, the embedded program is submitted and executed on the user's computer. This allows the hacker to obtain access permissions and steal sensitive data. Attackers use XSS to attack vulnerabilities on the victim's machine and transmit malicious code instead of attacking the system itself.

Attackers can modify and control the HTML code on the Web page by returning the Web form of the error message from the data entered by the user. Hackers can insert code into links in spam information or use fraudulent emails to entice users to trust their identities.

For example, an attacker can send an email with a URL to the victim. The URL points to a Web site and provides a browser script as the input; or publish malicious URL links on a blog or a social network such as Facebook or Twitter. When a user clicks this link, the malicious site and script will run on the browser. The browser does not know that the script is malicious and will blindly run this program. This allows attackers to use the website function to steal cookies or impersonate legitimate users to complete transactions.

How to Protect websites from cross-site scripting attacks?

Common cross-site scripting best practices include testing application code before deployment and quickly and concisely fixing defects and vulnerabilities. Web application developers should filter user input to remove possible malicious characters and browser scripts, and implant user input filtering Code to remove malicious characters. Generally, administrators can configure the browser to only accept scripts from trusted sites or disable the Script Function of the browser. However, this may restrict the use of Web sites.

With the development of the times, hackers have become more advanced, and the collection tool set is used to speed up the vulnerability attack process. This means that deploying these common XSS prevention practices is not enough, and the protection and prevention process must start from the underlying layer and continue to improve. The prevention process must begin at the development stage. Web applications built on a secure and secure development lifecycle methodology are unlikely to expose vulnerabilities in released versions. This not only improves security, but also improves availability and reduces the overall maintenance cost, because fixing problems in the field environment is more costly than during the development phase.

Threat modeling is also an important aspect in XSS prevention. It should be included in the security development lifecycle of each organization. Threat modeling evaluation and identification of all risks faced by applications during development, to help Web developers better understand what kind of protection is needed and what impact the organization will have if an attack succeeds. To identify the threat level of a specific application, it is very important to consider its assets and the sensitive information it accesses. This threat modeling process strategically integrates security factors in application design and development, and enhances the security awareness of Web developers.

For Web developers in large projects, source code scanning tools and Web application vulnerability scanners are the common choice for improving efficiency and reducing workload. Web vulnerability scanners can identify common defects and vulnerabilities-SQL injection, cross-site scripting, and buffer overflow. However, custom application code must be manually reviewed.