The OWASP Top Ten is a regularly updated list of the most critical web application security risks. It serves as a guide for developers and security practitioners to focus their efforts on addressing common vulnerabilities that could lead to security breaches. Here are the OWASP Top Ten vulnerabilities for 2021:
Let's dive into each of these vulnerabilities, understand what they are, and explore examples and mitigation strategies.
Description: Injection vulnerabilities occur when untrusted data is sent to an interpreter as part of a command or query. This can lead to unintended execution of malicious code.
Example: SQL Injection (SQLi) is a common form of injection. Imagine a user inputting '; DROP TABLE users;-- into a login field. If not properly sanitized, this could execute SQL commands, potentially deleting the "users" table.
Mitigation: Use parameterized queries or prepared statements to separate user input from SQL commands. Validate and sanitize input data.
Description: Broken authentication vulnerabilities arise when authentication mechanisms are not correctly implemented, allowing attackers to gain unauthorized access to accounts or sensitive data.
Example: Weak password policies or session management can lead to attackers easily guessing passwords or hijacking user sessions.
Mitigation: Implement strong password policies, multi-factor authentication (MFA), and secure session management practices.
Description: This vulnerability occurs when sensitive data (e.g., credit card numbers, personal information) is not adequately protected and can be accessed or stolen by unauthorized parties.
Example: Storing sensitive data in plain text instead of encrypting it. A data breach could expose user information.
Mitigation: Use strong encryption algorithms for data at rest and in transit. Follow best practices for data protection.
Description: XXE vulnerabilities allow attackers to interfere with the processing of XML data, leading to disclosure of internal files, denial of service, or remote code execution.
Example: An attacker sends malicious XML data that references an external entity, revealing sensitive file contents.
Mitigation: Disable XML external entity processing or use a secure XML parsing library.
Description: Broken access control vulnerabilities occur when users can perform actions or access data they should not have permissions for.
Example: A user with limited privileges accessing administrative features or viewing another user's private data.
Mitigation: Implement proper access controls, and enforce authorization checks on both the client and server sides.
Description: Security misconfiguration vulnerabilities stem from improperly configured security settings, exposing sensitive information or system weaknesses.
Example: Default login credentials left unchanged or overly permissive file permissions on a web server.
Mitigation: Regularly review and update security configurations, following best practices for the framework and platform in use.
Description: XSS vulnerabilities enable attackers to inject malicious scripts into web pages viewed by other users. These scripts can steal data or perform actions on behalf of the victim.
Example: An attacker injects a script into a comment section of a website. When other users view the comment, the script executes in their browsers, potentially stealing their session cookies.
Mitigation: Use input validation, output encoding, and security libraries to prevent XSS attacks.
Description: Insecure deserialization vulnerabilities occur when data from an untrusted source is deserialized without proper validation, leading to remote code execution.
Example: A web application deserializes data from a client request without verifying its integrity. An attacker could craft a malicious serialized object to execute arbitrary code on the server.
Mitigation: Avoid deserialization of untrusted data or use a safe deserialization mechanism.
Description: This vulnerability arises when outdated or insecure components (e.g., libraries, frameworks) are used in an application, providing opportunities for attackers to exploit known vulnerabilities.
Example: An application uses an old version of a JavaScript library with known security flaws.
Mitigation: Regularly update and patch all components, and monitor for security advisories.
Description: Insufficient logging and monitoring make it difficult to detect and respond to security incidents. Attackers can operate undetected, causing greater damage.
Example: An application lacks proper logging of authentication attempts, making it impossible to identify unauthorized access.
Mitigation: Implement comprehensive logging and monitoring, and establish incident response procedures.
