The Most Common Web Security Vulnerabilities

The Most Common Web Security Vulnerabilities

Websites and web applications, like any software, are subject to attacks by intruders who are trying to gain access to confidential information or personal data of users. This type of attack can be devastating to a business, not only financially, but can also leak trade secrets and other sensitive information.

Therefore, it is so important to be aware of the types of possible threats, as well as countermeasures. Since our company is actively promoting cybersecurity services, in this article we will look at the most dangerous types of website and web application vulnerabilities.

What are web application vulnerabilities?

A vulnerability is a flaw in the system or a security misconfiguration of a website or web application that attackers can use to gain unauthorized access, run malicious code, install malware, and steal confidential information.

Various methods and tools are used to access the system. Once cybercriminals discover a flaw, they use it to inject malicious code or content, and then do whatever they want with the system or users’ personal data.

Why are web applications vulnerable to attacks?

A website or web applications are attacked for various reasons. For example, due to system flaws that arise due to incorrect coding, server settings, application design flaws, etc. Such vulnerabilities allow attackers to gain access to databases that may contain confidential or other valuable information. Since web applications are constantly available to users, they are easy targets for attack.

Common types of web security vulnerabilities


Injections are among the top 3 vulnerabilities in modern web applications. These types of attacks occur when untrusted data is passed to the code interpreter via form entry or some other way of submitting information to a web application. For example, a cybercriminal might enter SQL into a form that expects a username. If the input at this point is not properly protected, it can lead to code execution. SQLi is especially dangerous if, as a result of the attack, the attacker gains access to sensitive data, such as personal information or user credentials.

Broken authentication

Authentication allows you to verify the identity of a user by associating incoming information with a set of user credentials, such as biometric data, password, etc. Authentication violation means that the session ID or user credentials have been stolen.

Such an attack can be caused by insufficient protection of credentials, a weak password and login, the transmission of a session ID, and other reasons. This allows an attacker to gain access to a user account, including privileged ones. And then use them to gain control over corporate information systems.


Cross-Site Scripting continues to be a dangerous threat to users and web applications. This vulnerability consists in the fact that malicious code is embedded in a web page and then executed in the user’s browser. In general, an attacker injects a script into a web application that triggers a loan for every user who visits the malicious page.

XXS vulnerabilities are typically used by cybercriminals to hijack user sessions, steal sensitive data, or redirect users to malicious sites.


XXE attacks target web applications that parse Extensible Markup Language (XML). They occur when input containing an XML code that references an external object is processed by a parser with a weak configuration. Such an attack can lead to the disclosure of sensitive data such as passwords, gaining access to files, or denial of service (DoS). XXE can also allow attackers to port scan and execute malicious code remotely.


Local File Inclusion is a popular method of hacking websites and applications, which allows a remote user to gain access using a specially crafted request to arbitrary files on the server, including those containing confidential information. This kind of hacking is possible when the check of incoming data and parameters in the website code is absent or insufficient.


Remote File Inclusion is a type of attack that uses the mechanisms of dynamic file inclusion in a web application. Attackers can use this mechanism to launch a remote file containing malicious code by a web application. Most application frameworks allow file inclusion, which is a useful mechanism for wrapping shared code into separate files, and then sharing them with various application modules. However, in this case, this can lead to a complete compromise of the entire system.


Cross-Site Request Forgery is a type of vulnerability when the server cannot understand where the request came from: from a real user or from a cybercriminal. It occurs because the browser automatically attaches the user’s cookie to HTTP requests. In this case, cookies are used to manage the user session in the application.  If successful, attackers can gain access to confidential information, change it, etc.

Use of software components with known vulnerabilities

Software components such as frameworks and libraries are often used in web applications to provide some functionality. At the same time, such components may contain vulnerabilities that attackers can use for their actions.

It is also a common problem that developers neglect to update third-party components, since their code may not work with new versions of software. In addition, cybercriminals are constantly looking for new vulnerabilities that have not yet been discovered by developers, and which they can also use.

Security misconfiguration

Mistakes in settings are one of the most common web security vulnerabilities. This also includes failure to fix software bugs, unused web pages, unprotected directories and files, default sharing permissions for cloud storage services, and unused or unneeded services.

Incorrect cybersecurity settings can be anywhere: in applications and web servers, databases, network services, user code, frameworks, and so on. Attackers can use these vulnerabilities to easily break into a web application and gain access to personal data, the functions of the application itself, and the entire system.

Weak monitoring

A successful hacker attack or data leak is not always easy to detect. Often, attackers not only gain unauthorized access to information systems, but manage them for a long time, remaining invisible.

To prevent this from happening, it is necessary to monitor the web application behavior and promptly respond to suspicious activity. Or prevent the attack at the very beginning, and if it has already happened, minimize its consequences.

Protection against common types of web application attacks

Although there are a huge number of ways to attack a web application or website, there are also processes and technologies that allow you to provide reliable protection against intruders. Different methods and approaches to web application security eliminate different vulnerabilities.

  1. For example, automated vulnerability scanning helps organizations find and fix vulnerabilities before an actual attack occurs. This kind of testing allows you to identify weaknesses and vulnerabilities in web security. You should try our free scan of your web resources. This security method combines the expertise of cybersecurity specialists with dynamic scanning tools to find security vulnerabilities in web applications.
  2. Constant monitoring of a website or application allows real-time monitoring of threats directed to a web resource. By the way, if your site is running on the WordPress platform, ESKA specialists are ready to provide you with a full package of services to ensure the monitoring of your website.
  3. Web application firewalls also help protect applications from security threats by filtering, monitoring, and blocking malicious or suspicious traffic directed to a web application. These hardware and software solutions are constantly updated to keep pace with new threats and are designed to detect the latest attack methods.
  4. Testing is a useful practice in which security specialists consider threats and attacks that may affect a web application. This procedure can help identify the latest security threats and attack vectors early in the product life cycle.

Penetration test

Separately, it should be said about  penetration testingPentesters conduct their test by simulating the actions of real attackers. Pentests differ in complexity and scope of actions, but in general, it all comes down to reconnaissance, finding vulnerabilities and gaining access to the system. In this way, real loopholes that cybercriminals can exploit can be identified, and then work can be done to eliminate these vulnerabilities.


Security is one of the key points to consider during the development and operation of modern web applications. To ensure a high level of protection against threats, information security, as well as compliance with applicable regulations, companies need to properly take care of this issue.

If you have any questions related to the security of web applications, or you need to test your cybersecurity system, please contact us in any way convenient for you. Or leave your contact details in a special form on our website, so that we can agree on a suitable time for consultation.