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CYBER SECURITY Tutorial
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Cross-Site Scripting (XSS)

Cybersecurity threats have evolved over the years, and one of the most prevalent yet often misunderstood threats is Cross-Site Scripting (XSS). XSS attacks target web applications, exploiting vulnerabilities that allow malicious scripts to be injected into otherwise trustworthy websites. These scripts then execute in the browsers of unsuspecting users, leading to various security breaches.

Types of Cross-Site Scripting (XSS)

1. Reflected XSS

Reflected XSS occurs when an attacker injects a malicious script into a URL, which is then reflected off a web server onto a victim’s browser. This type of attack often happens through phishing emails or deceptive links.

2. Stored XSS

Stored XSS involves injecting malicious scripts directly into a web application’s database. These scripts get stored and executed whenever the compromised data is retrieved, impacting all users accessing that particular data.

3. DOM-based XSS

DOM-based XSS occurs when the client-side script manipulates the Document Object Model (DOM) in an unsafe way, allowing the injection and execution of malicious scripts.

Impact of XSS Attacks

Data Theft and Leakage

XSS attacks can lead to the theft of sensitive user information, such as login credentials, personal details, or financial data. Attackers can exploit vulnerabilities to access this information without authorization.

Session Hijacking

By injecting malicious scripts, attackers can hijack user sessions, gaining unauthorized access to user accounts and performing actions on behalf of the victim.

Malware Distribution

Malicious scripts injected through XSS can also be used to distribute malware, infecting users’ devices and compromising their security.

Preventive Measures for XSS

1. Input Validation and Sanitization

Implement strict input validation to ensure that user inputs are properly sanitized before being processed or displayed.

2. Content Security Policy (CSP)

Utilize Content Security Policy headers to define trusted sources for content loading, minimizing the risk of executing malicious scripts.

3. Escape Untrusted Data

Escape untrusted data when rendering dynamic content to prevent it from being interpreted as executable code.

4. Regular Security Audits and Updates

Frequently audit your web applications for vulnerabilities and apply security patches and updates promptly