5 Common Types of Security Vulnerabilities (and How to Fix Them)

by Carson
5 types of security vulnerabilities

Other than telling your users to be careful with social engineering, you should also make sure that security flaws in your software get eliminated as soon as it’s found. Here are 5 common types of security vulnerabilities and how to fix them as quickly as possible.

Table of Contents

  1. Buffer overflows
  2. Lack of sanitization of inputs
  3. Authentication flaws
  4. Bugs within third-party software used
  5. Security misconfigurations

1. Buffer Overflows

To learn about buffer overflows, we first have to understand what buffers are. They are areas that store information that is going to be transferred. Unfortunately, it can be exploited to make weird things happen to the program by allocating more information to the buffer than it can withstand. For instance, if the buffer only has 16 bytes of capacity but needs to store 32 bytes of data, there is a buffer overflow.

If the data needs to get into the buffer, but there is no space to accommodate the information, where does it go? They might overwrite adjacent memory locations, resulting in potentially unpredictable behavior! What’s more, attackers can exploit this by replacing legitimate code with their malicious code by feeding the neighboring buffer with data until it is full.

For this reason, you should ensure that no data can be overwritten when the buffer gets full by implementing buffer overflow protection. This can check the length of the data to be transmitted into the buffer to produce an error whenever the allocated data cannot be fit into the buffer.

2. Lack of Sanitization of Inputs

Does your website accept all user input and process it directly to the server without filtering it? If so, your website is at risk of SQL injection attacks and cross-site scripting (XSS) attacks. Both attacks involve user inputs that the server essentially runs. For instance, a straightforward type of SQL injection attacks results in the attackers having full access to the victim’s account on the vulnerable website by typing this string into the password field:

' or 1=1

This quotation mark essentially tells the server to end the string so that the instruction “or 1=1” can be executed, instructing the server to finish the authentication process regardless of whether the password is correct.

To prevent these attacks from succeeding, you should escape special characters like quotation marks in all user input and produce an error if there is a potentially malicious request. That way, the server will process the input as if it’s a regular string, and will not produce unexpected behavior even if the string is ended by a quotation mark.

A warning displayed by Wordfence when the <script> tag is added to the URL as a parameter

3. Authentication Flaws

Authentication and session management systems need to be implemented correctly in apps and websites. If not, it can lead to the unauthorized access of personal information within the users’ accounts. For instance, once hackers obtain the session ID for whatever reason, the server will think that the hackers who stole the session ID are a legitimate users, thus giving them permission to obtain and manipulate the confidential information inside the user’s account, or even gaining complete control of it without the victim even realizing it.

4. Bugs Within Third-party Functions Used

To speed up the process of programming, you should use third-party functions or APIs, including built-in ones and/or ones imported from available modules. However, keep in mind that those functions contain bugs, too, and those imperfections might enable hackers to create backdoors even if you do everything else right.

To prevent hackers from exploiting these vulnerabilities, you should always use the latest version of apps, modules, APIs, and programming languages. As a result, you should proactively check for updates for all software if it isn’t done automatically.

5. Security Misconfigurations

Last but not least, security vulnerabilities can exist out of any piece of code. In fact, they might stem from security misconfigurations. For instance, if you use the default router password, enable features that give off more personal information of your clients than necessary, or reveal excessive amounts of debugging information in error messages, you increase the chances of your website being hacked.

When you finish debugging and put your updated version of your code on your website, you should never see something like this if an error has been encountered.

To combat this problem, you should double-check to ensure that all configurations are correct according to your security policy after a change in configurations, often for debugging. Besides, check for problems in your configurations regularly, and try to force the website to display error messages so that you ensure that no confidential information can be exposed from them.

How to Find Security Vulnerabilities?

You might think that just scanning your code for errors is the most effective way to find most security vulnerabilities, but it’s not enough. Therefore, if your business has an app or an API, you should hire white-hat hackers to continuously attack your systems so that vulnerabilities can be found and fixed as early as possible. Furthermore, you should reward users who discover security bugs in your system and report them to your company. They might accidentally find something that your white-hat hackers didn’t spot.

However, be aware that even with professionals, some security imperfections may not be found until months of years after hackers have actively exploited them to compromise users. They are known as zero-day exploits, and the only thing that companies can do about that is to find security flaws more efficiently.


In this article, we mentioned 5 primary types of security vulnerabilities and how to fix them. If you want to learn more, please visit the webpages in the references below.

References and Credits

  1. (n.d.). What is buffer overflow? Retrieved December 21, 2021, from https://www.cloudflare.com/learning/security/threats/buffer-overflow/
  2. (n.d.). Buffer Overflow Attack. Retrieved December 21, 2021, from https://www.imperva.com/learn/application-security/buffer-overflow/
  3. (n.d.). What Is Buffer Overflow? Retrieved December 21, 2021, from https://www.fortinet.com/resources/cyberglossary/buffer-overflow
  4. (n.d.). Using SQL Injection to Bypass Authentication. Retrieved December 21, 2021, from https://portswigger.net/support/using-sql-injection-to-bypass-authentication
  5. (n.d.). Session hijacking attack. Retrieved December 21, 2021, from https://owasp.org/www-community/attacks/Session_hijacking_attack
  6. Anastasios Arampatzis. (2021, April 12). What is Session Hijacking? Retrieved December 21, 2021, from https://www.venafi.com/blog/what-session-hijacking

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