Command Injection is a type of attack in cybersecurity where an attacker injects malicious commands into the input variables of a system. These input variables are typically interpreted by an application or program and passed to the operating system to execute commands. A successful Command Injection attack allows the attacker to execute undesired commands, leading to various types of damage, such as:

1. Executing system commands: The attacker can inject system commands to create, delete, or modify files, start or stop processes, perform network communication, or carry out other malicious actions.

2. Stealing confidential information: By executing commands, the attacker can access confidential information stored on the affected system. This may include user accounts, passwords, sensitive files, and other critical data.

3. Compromising the system: A successfully executed Command Injection attack can result in the attacker gaining full control over the affected system. This can lead to the installation of backdoors, takeover of administrator privileges, or execution of other malicious activities.

Command Injection attacks are commonly found in web applications, scripts, and other software applications that process user input and pass it to the operating system. To prevent such attacks, it is essential to thoroughly validate inputs, ensure that user data is not directly concatenated into commands, and implement security mechanisms such as using secure APIs and adhering to the principle of least privilege.

Cross-Site Scripting (XSS) is a security vulnerability in web applications where attackers inject malicious code (typically JavaScript) into web pages that are then executed by other users of that website. This often occurs by the attacker inserting the malicious code into input fields or parameters of a web page, which is then passed on to other users without proper filtering.

There are various types of XSS attacks, including:

1. Reflected XSS: The malicious code is inserted into a URL and passed on to a user who then clicks on that URL. The application processes the input and executes the code, resulting in an attack.

2. Persistent XSS: The malicious code is stored permanently in the database or on the server and is served to all users visiting the affected page.

The impacts of XSS attacks can be diverse, including:

• Theft of cookies and session information to access user accounts.
• Redirection to phishing pages or malware downloads.
• Manipulation of content on the website to display fake messages or deceive users.
• Exploitation of browser vulnerabilities to take over user accounts or execute further malicious code.

To protect against XSS attacks, web developers should properly validate and sanitize user inputs before displaying them on the website. Additionally, security mechanisms like Content Security Policy (CSP) can be implemented to prevent the execution of malicious code. Users should also exercise caution and avoid clicking on suspicious links or entering information on insecure websites.

SQL injection (SQLI) is a type of attack where an attacker injects malicious SQL code into input fields or parameters of a web page, which is then executed by the underlying database. This attack method exploits vulnerabilities in input validation to gain unauthorized access to or manipulate the database.

An example of SQL injection would be if an attacker enters an SQL command like "OR 1=1" into the username field of a login form. If the web application is not adequately protected against SQL injection, the attacker could successfully log in because the injected SQL command causes the query to always evaluate to true.

SQL injection can have various impacts, including:

1. Disclosure of confidential information from the database.
2. Manipulation of data in the database.
3. Execution of malicious actions on the server if the database supports privileged functions.
4. Destruction or corruption of data.

To protect against SQL injection attacks, web developers should employ secure programming practices, such as using parameterized queries or ORM (Object-Relational Mapping) frameworks to ensure all user inputs are handled securely. Additionally, it's important to conduct regular security audits and promptly install security patches.

Broken Access Control refers to a vulnerability in the security configuration of an application or system that allows an attacker to access resources they shouldn't have permission to access. This vulnerability occurs when access control mechanisms are not properly implemented or enforced.

Broken Access Control typically occurs when:

1. User permissions are not correctly checked before granting access to a resource.
2. Direct accesses to URLs, files, or other resources are possible without access control checks.
3. Access controls are based on outdated or inadequate authentication or authorization methods.
4. Faulty configurations or inadequate security policies allow an attacker to bypass or escalate permissions.

This vulnerability can have serious consequences as it can allow an attacker to access sensitive data, manipulate systems, or perform other malicious actions for which they shouldn't have permission. To avoid Broken Access Control, it's crucial to implement a robust access control strategy that ensures only authorized users can access the appropriate resources and that all accesses are properly checked and enforced.