svrjs-blog/source/_posts/Top-10-Most-Common-Web-Application-Vulnerabilities.md

---
title: Top 10 Most Common Web Application Vulnerabilities
date: 2024-05-30 15:02:42
tags:
 - cybersecurity
 - web
 - webmaster
category: Tips
thumbnail: /images/covers/Top-10-Most-Common-Web-Application-Vulnerabilities.png
---
Web application vulnerabilities are very important to be aware of because they can be used by attackers to steal sensitive data, such as passwords or credit card data or to gain unauthorized access to the application. These vulnerabilities may even be used to launch attacks at other systems or to break the application.

In this post, we will showcase 10 most common vulnerabilities found in web applications.

**WARNING: We’re not responsible for damage caused by exploiting vulnerabilities in web applications! Malicious hacking is a computer crime and you may face legal consequences! This post is meant to gain awareness about vulnerabilities in web applications and give a way to prevent those vulnerabilities.**

## 1. Injection

Injection vulnerabilities occur when an attacker is able to inject malicious code or data into queries or system calls made by a web application. This can allow the attacker to access or  even modify the application data, possibly breaking the application.

There are several types of injection vulnerabilities, including:

*    **SQL injection** - this occurs when an attacker is able to inject malicious SQL code into a query that is executed by the application. This can allow the attacker to access or modify data in the database, or to execute arbitrary SQL commands. [You can read more about SQL injection vulnerabilities.](https://blog.svrjs.org/2023/12/02/What-is-SQL-injection-How-to-prevent-it/)
*    **Command injection** - this occurs when an attacker is able to inject malicious commands into a system call that is made by the application. This can allow the attacker to execute arbitrary commands on the underlying system with the privileges of the application.
*    **LDAP injection** - this occurs when an attacker is able to inject malicious LDAP code into a query that is executed by the application. This can allow the attacker to access or modify data in the LDAP directory, or to execute arbitrary LDAP commands.

To prevent injection vulnerabilities, it is important to use input validation and sanitization techniques to ensure that user-supplied data is safe to use in queries and system calls. It is also important to use parameterized queries and prepared statements when working with databases, as these can help to prevent SQL injection attacks.

## 2. Broken Authentication and Session Management

Weak authentication and session management can allow attackers to gain unauthorized access to web applications in several ways.

One way is by using brute force attacks to guess or crack weak passwords. If an attacker is able to guess or crack a user's password, they can then log in to the application and access the user's data or functionality.

Another way is by exploiting weaknesses in the way that the application manages sessions. A session is a period of time during which a user is logged in to the application and can access their data and functionality. If an attacker is able to hijack or steal a user's session, they can then impersonate the user and access their data and functionality.

Weaknesses in session management can include things like not properly invalidating sessions after a user logs out, not using secure or unpredictable session tokens, or not properly protecting session tokens from being stolen or intercepted.

To prevent weak authentication and session management vulnerabilities, it is important to use strong passwords and to implement proper session management practices, such as properly invalidating sessions after a user logs out, using secure and unpredictable session tokens, and properly protecting session tokens from being stolen or intercepted. It is also important to use multi-factor authentication (MFA) where possible, as this can provide an additional layer of security against brute force attacks and session hijacking.

## 3. Cross-Site Scripting (XSS)

Cross-Site Scripting (XSS) vulnerabilities can be exploited by attackers to inject malicious scripts into web pages.

XSS vulnerabilities occur when an application does not properly validate or sanitize user-supplied data that is included in a web page. This can allow an attacker to inject malicious scripts into the web page, which will then be executed in user's browser.

The potential consequences of an XSS attack can depend on the specifics of the attack and the vulnerability being exploited. However, some common consequences of XSS attacks include:
*   **Stealing user data** - an attacker can use an XSS vulnerability to inject a script that steals sensitive data, such as login credentials or credit card numbers, from the user's browser.
*   **Defacing the website** - an attacker can use an XSS vulnerability to inject a script that modifies the appearance of the website, such as by adding or removing content.
*   **Launching further attacks** - an attacker can use an XSS vulnerability to inject a script that launches further attacks on the user or the application, such as by exploiting other vulnerabilities or by redirecting the user to a malicious website.

To prevent XSS vulnerabilities, it is important to use input validation and sanitization techniques to ensure that user-supplied data is safe to include in a web page. It is also advisable to use Content Security Policy (CSP) and other security measures to prevent the execution of malicious scripts in the browser.

[You can read more about cross-site scripting vulnerabilities.](https://blog.svrjs.org/2024/05/07/What-is-cross-site-scripting-How-to-prevent-it/)

## 4. Broken Access Control

Weak access controls can allow attackers to access sensitive data or functionality within a web application by exploiting vulnerabilities in the way that the application controls access to its resources.

Access controls are used to ensure that only authorized users are able to access certain resources within the application, such as data, functionality, or pages. If the access controls are weak or not properly implemented, an attacker may be able to bypass them and access the resources without authorization.

There are several ways that weak access controls can be exploited, including:

*   **URL tampering** - an attacker may be able to access sensitive resources by modifying the URL of the resource in their browser. For example, if the application uses predictable URLs for its resources, an attacker may be able to guess the URL of a sensitive resource and access it directly.
*   **Parameter tampering** - an attacker may be able to access sensitive resources by modifying the parameters of a request to the application. For example, if the application uses parameters to specify which data to display, an attacker may be able to modify the parameters to access data that they are not authorized to view.
*   **Session tampering**- an attacker may be able to access sensitive resources by tampering with the session of a user who is authorized to access the resources. For example, if the application does not properly validate the session when a user accesses a resource, an attacker may be able to impersonate the user and access the resource without authorization.

To prevent weak access controls vulnerabilities, it is important to use proper access control mechanisms, such as role-based access control (RBAC) or access control lists (ACLs), to ensure that only authorized users are able to access certain resources. It is also important to use secure and unpredictable URLs and parameters, and to properly validate the session when a user accesses a resource.


## 5. Security Misconfiguration

Misconfigured servers, frameworks, and applications can leave web applications vulnerable to attack in several ways.

One way is by exposing versions of servers, frameworks and applications. Exposing versions of web application may make it easier for the attacker to find vulnerabilities and a right exploit for the application.

Another way is by exposing sensitive data or functionality that should not be publicly accessible. For example, if a server is misconfigured and does not properly restrict access to certain directories or files, an attacker may be able to access and download sensitive data or exploit vulnerabilities in the exposed functionality.

Another way is by allowing attackers to bypass security controls or exploit vulnerabilities that would otherwise be protected. For instance, an attacker might be able to introduce malicious code or data into the application and take advantage of a vulnerability if a framework is improperly configured and does not properly implement input validation or sanitization.

Misconfigurations can also occur at the application level, such as when an application does not properly configure its security settings or does not properly implement security controls.

To prevent misconfigurations from leaving web applications vulnerable to attack, it is important to follow best practices for configuring servers, frameworks, and applications. This can include things like properly restricting access to sensitive data and functionality, implementing input validation and sanitization, and properly configuring security settings. It is also important to regularly review and audit the configurations of servers, frameworks, and applications to ensure that they are secure and up to date.

## 6. Sensitive Data Exposure

Sensitive data, such as passwords and credit card numbers, can be exposed if not properly protected in several ways.

One way is by storing the data in an unencrypted or poorly encrypted form. If an attacker is able to access the data, either by exploiting a vulnerability in the application or by physically accessing the storage device, they will be able to read the data and potentially use it for malicious purposes.

Another way is by transmitting the data over an insecure or poorly encrypted communication channel. If an attacker is able to intercept the data, either by exploiting a vulnerability in the application or by physically accessing the communication channel, they will be able to read the data and potentially use it for malicious purposes.

Sensitive data can also be exposed if it is not properly protected when it is being used or processed by the application. For example, if the application does not properly validate or sanitize user-supplied data, an attacker may be able to inject malicious data or code into the application and access or modify the sensitive data.

To prevent sensitive data from being exposed, it is important to use proper encryption and secure communication channels when storing or transmitting the data. It is also important to use input validation and sanitization techniques to ensure that user-supplied data is safe to use, and to properly protect the data when it is being used or processed by the application.

## 7. Insufficient Input Validation

Weak input validation can allow attackers to inject malicious data into web applications by exploiting vulnerabilities in the way that the application handles user-supplied data.

Input validation is the process of validating user-supplied data to ensure that it is safe to use and meets certain requirements, such as being of a specific type or format. If an application does not properly validate user-supplied data, an attacker may be able to inject malicious data or code into the application and exploit a vulnerability.

For example, if an application does not properly validate user-supplied data that is included in a query or system call, an attacker may be able to inject malicious code or data into the query or system call and exploit an injection vulnerability.

Weak input validation can also make it possible for attackers to inject malicious data into the application through other vulnerabilities like cross-site scripting (XSS) or weaknesses in the program's data processing or storage procedures.

To prevent weak input validation vulnerabilities, it is important to use input validation and sanitization techniques to ensure that user-supplied data is safe to use. This can include things like checking the type and format of the data, using regular expressions to validate the data, and using functions or libraries to sanitize the data. It is also important to use parameterized queries and prepared statements when working with databases, as these can help to prevent injection attacks.

## 8. Cross-Site Request Forgery (CSRF)

Cross-site request forgery (CSRF) vulnerabilities could lead users to do unintended actions on a web application.

CSRF vulnerabilities occur when an application does not properly verify the origin of a request, allowing an attacker to craft a malicious request and trick the user's browser into sending it to the application.

For example, a user is logged into a web application and is seeing a page with an account transfer form on it. An attacker could create a fraudulent request with the attacker's account as the recipient and a large transfer amount, and then trick the user's browser into sending the request to the application. The application might process the request and transfer the funds to the attacker's account if it fails to properly validate the request's origin.

CSRF vulnerabilities can be used to perform a wide range of malicious actions, including stealing sensitive data, modifying data or settings, and making unauthorized purchases or transactions.

To prevent CSRF vulnerabilities, it is important to use proper CSRF protection mechanisms, such as including a unique and unpredictable token in forms and verifying the token when the form is submitted, or using the *SameSite* cookie attribute to restrict the cookies that are sent with cross-origin requests. It is also important to properly validate and sanitize user data to ensure that it is safe to use.

[You can read more about cross-site request forgery vulnerabilties.](https://blog.svrjs.org/2024/05/14/What-is-cross-site-request-forgery-How-to-prevent-it/)

## 9. Using Components with Known Vulnerabilities

Using outdated or vulnerable components, such as libraries and frameworks, can leave web applications vulnerable to attack in several ways.

One way is by allowing attackers to exploit known vulnerabilities in the components. If a component has a known vulnerability and the application uses an out-of-date or vulnerable version of the component, an attacker might be able to take the advantage of the vulnerability and compromise the security of the application.

Another way is by introducing new vulnerabilities into the application. If a component has a vulnerability that is not yet known or has not been patched, and the application is using the vulnerable version of the component, an attacker may be able to discover and exploit the vulnerability.

Using outdated or vulnerable components can also leave the application vulnerable to attack by reducing the overall security of the application. For example, if the application is using an outdated or vulnerable version of a library or framework that is responsible for handling input validation or sanitization, the application may be more vulnerable to injection attacks or other types of attacks that rely on weak or broken input validation.

To prevent using outdated or vulnerable components from leaving web applications vulnerable to attack, it is important to keep the components up to date with the latest security patches and to use components that are known to be secure and well-maintained. It is also important to regularly review and audit the components that are being used in the application to ensure that they are secure and up to date.

## Conclusion

In conclusion, web application vulnerabilities are a significant security concern for organizations and individuals alike. In this post, we have highlighted the top 10 most common vulnerabilities found in web applications, including injection, broken authentication and session management, cross-site scripting (XSS), broken access control, security misconfiguration, sensitive data exposure, insufficient input validation, cross-site request forgery (CSRF), and using components with known vulnerabilities.

It is important to be aware of these vulnerabilities and to take steps to prevent them in order to protect the security of web applications and the data they store. This can include implementing secure coding practices, conducting regular security testing and vulnerability assessments, and keeping software and systems up to date with the latest security patches.

We hope that this post has provided useful information and resources for those looking to improve the security of their web applications. **However, we would like to remind our readers again, that this post is meant for educational and awareness purposes only. Malicious hacking is a computer crime and you may face legal consequences. We are not responsible for any damage caused by exploiting vulnerabilities in web applications.**