Use Cases



Security is an integral part of any application. With several applications delivering several services and functionalities on the web and remote work becoming the norm, web applications have become primary targets for hackers. Not only that, though. The cost of vulnerabilities can also be incredibly steep or damaging to any company. According to the 2021 Data Breach Report from IBM, the average cost of a data breach rose to $4.24 million from a previous year's average of $3.86 million.

OWASP is a nonprofit organization that serves as a neutral resource for information on developing secure web applications and providing security best practices. The term OWASP stands for Open Web Application Security Project. It was founded in 2001 specifically to help organizations and cybersecurity professionals protect and defend against cyber attacks and vulnerabilities.

This article describes the top 10 OWASP security vulnerabilities you need to know about.

What are the OWASP Top 10 Vulnerabilities For 2021

The annual OWASP Top 10 vulnerabilities present an authoritative guide on web application vulnerabilities and protection measures. You will learn about the vulnerabilities, how each mistake can negatively impact your business, and how to mitigate the risks. 


By now, you’ve probably heard of an injection attack. It is one of the most prominent security attacks. Even though injection attacks are not particularly difficult to defend against, they remain relatively prevalent. SQL injection is the most common type of injection. Other types of injection vulnerabilities include CSS, NoSQL, and LDAP injection. 

Injection attacks occur when an untrusted code is inserted into your application’s database query or command, causing it to execute malicious commands without the appropriate validation of its payloads.

With a successful attack, hackers can gain complete access to your application data, impersonate a user, bypass authentication, or launch a variety of attacks on your internal network. 

You can protect yourself from injection attacks by validating and cleaning every data request you receive or by using object-relational mapping (ORM) for dynamic queries.

Broken Authentication

 A broken authentication vulnerability occurs when an attacker gains unauthorized access to credentials such as user names, passwords, and session tokens, giving them access to user data on a temporary or permanent basis. 

For instance, an attacker could execute a script to attempt hundreds of known username/password combinations on a login system to determine if any of them work based on a list of thousands of possible combinations obtained during a data breach. 

To mitigate this vulnerability, you can use two-factor authentication or limit or delay the number of repeated login attempts.

Sensitive Data Exposure

Developers use API to help connect web and mobile applications to third-party services. This particular vulnerability occurs when applications make API calls and return more data than necessary, allowing hackers to exploit the API response and access sensitive data. 

Rather than sending only the required information, API developers may send generic information as payload response back to the client-side, putting the responsibility of filtering the data on the frontend developer. In this case, the attacker will try to access sensitive data by looking through the payload, leading to several Man-in-the-Middle attacks. 

You can reduce the risk of sensitive data exposure by disabling response caching, using encryption, proper key management, and tokenization.

XML External Entities (XXE)

Numerous poorly configured or older XML processors can be exploited when parsing external entity references inside an XML document. Attacks take place by uploading malicious XML documents from unreliable sources. That way, a hacker can use an external entity to exploit internal files through the URL handler. In addition to this, hackers may access internal files, scan internal ports, execute remote requests, and perform denial of service attacks (DoS).

You can easily prevent this attack by disabling external XML entities parsing all XML parsers or by using a simplified data format, such as JSON. However, if you must use XML, be sure to patch and update your XML libraries, dependencies, and processors.

Broken Access Control

Consider a scenario where a user within your application has greater access than necessary, such as admin rights. It may be very damaging to you, but for an attacker, it’s a golden opportunity. 

As the name suggests, broken access control simply means that a hacker gains access to your application either as an administrator or user, giving them unintended privileges. With that access, the hacker may modify or delete sensitive data. 

A compromised account can cause havoc on your systems if you do not limit access exclusively to authenticated users. To address this vulnerability, be sure to establish a clear and isolated set of privileges for each role using secure access control procedures.

Security Misconfigurations

Similar to the vulnerabilities with access control, security configurations are always a point of risk that attackers can exploit to get access to sensitive data. Server components often come with default settings that are insecure, resulting in data leakage. The security settings of an application, web server, or operating system may be improperly configured or not regularly updated. 

There are several ways that these attacks can occur, such as setting up unnecessary ports, logging in with default credentials, poorly configured HTTP headers or encryption, and issuing misleading error messages with too many details about the application.

Security configurations become more secure using automated scanners. To prevent these attacks from occurring, you may want to put in place a patch management procedure that removes obsolete software and features, as well as unnecessary code.

Cross-Site Scripting (XSS)

Cross scripting vulnerability occurs when a hacker injects client-side scripts into an application through poor validation and user input encoding. In a way, it is similar to an HTML injection since the injection takes place in the user’s browser rather than on the server, making it possible for a hacker to gain access to session cookies. 

A successful XSS attack relies on browsers trusting the code they need to load as secure. In this kind of attack, a person's confidential and personal information and the CVC code on a credit card can be susceptible to theft. 

Another scenario is that hackers can change the information on specific website pages using JavaScript, such as changing bank transfer details to fake and replacing them.

To avoid this challenge, be sure to use a framework that disallows the usage of XSS. Also, If you want to insert data that is not trusted, you should encode it with HTML.

Insecure Deserialization

With deserialization, a hacker can manipulate the logic of an application and launch a DoS attack or run arbitrary code. 

You should update and sync all logs with the server while ensuring consistency with every other aspect of your application. Also, you can implement an automated log monitoring system. 

Using Components with Known Vulnerabilities

You’ll often need to integrate and execute third-party libraries, frameworks, or other components with similar privileges as your application. APIs and applications using vulnerable libraries can expose applications and make them more vulnerable to other types of attacks. It’s a common mistake to overlook these vulnerabilities. Exploiting a vulnerable component can result in data loss or server takeover.

You should continually monitor all external components if you want to prevent such a vulnerability. The best solution is to use an automated monitoring tool that notifies you whenever a flaw appears, or an application needs to be updated.

Insufficient Logging and Monitoring

The security of an application is only guaranteed by regularly logging and monitoring it. A large number of web applications fail to detect data breaches on time. After a breach occurs, it takes an average of about 200 days for detection. That is why you need to audit, monitor, and log all activities. Failure to do so may result in seriously adverse consequences. 

By carrying out penetration testing and developing a response plan, you can thoroughly examine the test logs and identify security flaws.

Enforcing The Best Security Practices

With the OWASP top 10, you have a thorough understanding of how your application can be exploited. However, you’ll have to implement the best security practices to prevent these vulnerabilities. Here are a few things to put in mind when it comes to protecting your application.

If you want to read more about Zesty.io’s security practices and guidelines, read more here: Zesty.io's Security Practices

By Stuart Runyan

Developing web technologies is my passion! I'm focused on creating applications and experiences to solve the problems which today's digital marketers face. I believe in web standards, a mobile first approach, access for everyone, open source software and the democratization of information. My goal is to continue the Internet being pure awesome!

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