OWASP Top Ten 2023 – The Complete Guide

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OWASP 2023 is a big deal because this list of the 10 most serious web app security vulnerabilities ranks them in order of risk. It’s an important checklist of threats to guard against for web developers as well as anyone who is responsible for website security or web app development. 

OWASP stands for Open Worldwide Application Security Project, and it’s a non-profit foundation that creates web application security resources. It produces a risk assessment framework, industry standards, best practices, tools, and more, and anyone in its community can contribute, so it has a vast pool of expertise on tap.

To compile its top 10 list of security vulnerabilities OWASP regularly gathers data from more than 200,000 organizations and from surveys of industry professionals. With a new update yet to surface (we’re expecting one sometime in the next couple of years), OWASP 2023 inevitably relies on the 2021 list, but make no mistake, these vulnerabilities are still very relevant and everyone in web development and security needs to be alert to the threats they pose.

Top Ten Vulnerabilities for OWASP 2023

1. Broken Access Control

Rising from 5th place in 2017 to top the list in 2021, broken access control remains a significant, ongoing threat. Access controls limit users to the resources and functionalities they are authorized to use, and broken access control is the term used when a system fails to enforce appropriate restrictions.

This can happen for various reasons, including a misconfiguration, IDOR (Insecure Direct Object References) which is where an application exposes direct references to resources like files or database records, insecure session management, where flaws in session management can allow attackers to hijack users’ sessions, and others.

Developers and system administrators should follow the Principle of Least Privilege here, which means only granting users the minimum set of permissions that are required for them to perform their tasks and nothing more.

All user input should be validated and sanitized to prevent attackers from injecting malicious data, access controls should be applied to APIs, and authorization checked for every request.

Regular security audits and code reviews are a must to identify and fix access control issues, and multi-factor authentication should be enforced to limit unauthorized access.

2. Cryptographic Failures

This was previously in the number three spot and was called “Sensitive Data Exposure” but it’s since been relabeled because the old name described a symptom rather than the cause. Cryptography is used to protect highly sensitive data like credit card numbers and PII while it’s in transit, but it can fail due to factors like weak encryption algorithms or short encryption keys which can make it easier for attackers to decrypt sensitive data.

Other examples of cryptography failures include insecure password storage, insufficient transport layer security (which can lead to man-in-the-middle attacks), weak SSL/TLS protocols, and insecure cipher suites that can expose the web application to attacks.

Implement regular security testing (including code reviews and vulnerability assessments) to identify and fix cryptographic weaknesses, and also consider using secure cryptographic libraries too.

3. Injection

Injection occupied the 2017 number one spot and cross-site scripting the number seven. Now they’ve been consolidated under this one umbrella term which occupies the current number three position for OWASP 2023.

Injection attacks exploit vulnerabilities in input validation and inadequate data handling. Attackers inject data such as SQL queries, code snippets, or commands into web application forms or URLs. They allow adversaries to access sensitive data and manipulate an application’s behavior.

Examples include:

·       SQL Injection for database attacks

·       Cross-Site Scripting (XSS)—usually JavaScript-based browser attacks launched via infected web pages, leading to session hijacking, cookie theft, or other attacks on users.

·       Command Injection—attackers inject malicious commands into system commands executed by the application, potentially gaining control of the server or executing unauthorized operations.

·       LDAP Injection—attackers manipulate LDAP queries used for authentication and authorization to gain access.

·       XML Injection—attackers insert malicious content into XML data, potentially disrupting the application’s parsing process to gain access.

·       Server-Side Template Injection (SSTI)—where attackers inject malicious code into server-side templates to execute code on the server.

4. Insecure Design

This OWASP 2023 category was new in 2021, and it covers faulty application design and flaws in architecture that hackers can exploit. Insecure design vulnerabilities occur when teams don’t adhere to security best practices, and they fail to adequately anticipate and evaluate potential threats during the code design phase of creating the application.

An example of insecure design is an app that produces overly detailed error messages. If it reports on error conditions in too much detail and offers diagnostic clues about the application environment, or other associated data, it could be revealing potentially useful information to attackers. They could then use it to launch other attacks like path transversal or SQL injection.

It’s important to mitigate design vulnerabilities by using consistent threat modeling to shut down known methods of attack.

5. Security Misconfiguration

This category now includes 2017’s XML External Entities (XXE) category. Security misconfigurations encompass a variety of potential vulnerabilities, but these are the most common ones:

·       Unpatched vulnerabilities

·       Default configurations

·       Unused pages

·       Unprotected files and directories

·       Unnecessary services

·       Use of vulnerable XML files

A common mistake that webmasters commit is leaving CMS (Content Management System) default configurations unchanged. While CMS apps are user-friendly, they can pose security risks for end-users. Many attacks are entirely automated and rely on exploiting default settings, which makes changing these settings during CMS installation crucial for mitigating a significant number of potential attacks.

Adjusting settings to control comments, user access, user information visibility, and default file permissions can bolster security.

6. Vulnerable and Outdated Components

Even the simplest of websites have many dependencies like frameworks, libraries, extensions, and plugins, and every one of them must be kept up to date. Attackers are actively looking for websites with vulnerable components which they can exploit to spread malware, launch phishing attacks, and more, so failing to install updates for whatever reason is a bad idea.

The latest version of any software is going to contain the latest security updates, but if your website relies on a lot of dependencies that can be easier said than done. The first step to fixing this is to create an inventory that lists all the connected components in your environment and keeps you up to date on each one’s behavior, something that Reflectiz can do for you automatically.

7. Identification and Authentication Failures

Authentication and identity management failures expose applications to the risk of malicious actors posing as genuine users. A session ID configured without a validity period can run and run. Weak passwords can be susceptible to guessing and with no rate limits imposed on login attempts automated attacks keep doing that until they succeed.

To address these issues, implement multi-factor authentication (MFA) within applications. Also, developers should be made aware of the need to adhere to recommended password length, complexity, and rotation policies.

8. Software and Data Integrity Failures

These are a type of design flaw. The complexity of modern architectures means that developers often add plugins and libraries to the pipeline from various sources without verifying their integrity. If any of them fail, this can leave applications susceptible to unauthorized information disclosure, system compromise, or malicious code insertion. This is another reason why it’s important to have an active inventory of all third-party and open-source plugins and libraries, along with continuous threat monitoring.

9. Security Logging and Monitoring Failures

Poor logging and monitoring capabilities mean that incidents are missed and alerts aren’t generated, and they could remain unnoticed for long enough to do substantial damage.

Login attempts and failures need to be logged, and logs need to be backed up in case of server failure. Logs need to be accurate so that monitoring systems can detect suspicious activities or raise timely alerts, and they also need to be protected against tampering.

To mitigate vulnerabilities, record all login attempts (including failures), maintain copies of logs, use anti-tamper mechanisms, and test monitoring systems regularly.

10. Server-Side Request Forgery (SSRF)

This vulnerability allows attackers to make unauthorized requests from the server to other internal or external resources. In SSRF attacks, the attacker can manipulate input fields or parameters in the application to trick the server into sending requests to arbitrary URLs, often without the user’s knowledge.

Attackers can abuse this vulnerability to access sensitive data, interact with internal resources, or perform actions on behalf of the server, potentially leading to a complete compromise of the application or its infrastructure.

To mitigate SSRF vulnerabilities, developers should follow best practices such as:

Input Validation: Properly validate and sanitize user-supplied input to prevent malicious URLs or IP addresses from being used in requests.

Whitelisting: Implement whitelisting for allowed URLs or IP ranges to restrict the server’s ability to make requests to known safe resources.

Firewall Rules: Configure firewalls and network settings to restrict outgoing requests from the server to specific resources and protocols.

Use of Safe APIs: If the application needs to make requests to external resources, use safe APIs or specific endpoints that are intended for public access.

Least Privilege: Ensure that the server has the least privileges necessary to access external resources to limit potential damage if an SSRF attack occurs.

These Are the Risks. Time to Get Protected

OWASP 2023 provides a useful guide to combatting some of the most challenging vulnerabilities that go with using large numbers of web apps, and you can manage many of them with Reflectiz. Our continuous monitoring platform keeps you informed with a complete list of all third- and fourth-party applications running on your website, including their scripts, geolocations, and relationships. It keeps you up to date with potential compliance issues and vulnerabilities so that you can act on them before it’s too late. It generates alerts and allows you to block malicious domains, and put all of these features at your fingertips via a powerful but simple, user-friendly dashboard.

Talk to us at Reflectiz today and learn more about how continuous monitoring can keep your business safe.

FAQs

What causes Identification and Authentication Failures in web applications?

Identification and Authentication Failures (#7 on OWASP 2023) occur when applications have weak session management, allow weak passwords without complexity requirements, or impose no rate limits on login attempts — enabling automated brute-force attacks. Sessions without validity periods can persist indefinitely, increasing exposure. Mitigations include implementing multi-factor authentication (MFA), enforcing strong password policies, and training developers on secure session management practices.

What is Insecure Design in OWASP 2023?

Insecure Design (ranked #4) is an OWASP category introduced in 2021 that addresses fundamental flaws in application architecture and design — not just implementation bugs. It occurs when development teams fail to apply security best practices during the design phase and do not perform adequate threat modeling. A classic example is an application that returns overly detailed error messages, inadvertently revealing diagnostic information that attackers can exploit to launch SQL injection or path traversal attacks.

What is number one on the OWASP Top Ten 2023 list?

Broken Access Control is number one on the OWASP Top Ten 2023 list. It rose from 5th place in 2017 to the top spot in 2021 and remains the most prevalent web application vulnerability. It occurs when a system fails to enforce appropriate restrictions on what authenticated users are allowed to do — caused by misconfigurations, Insecure Direct Object References (IDOR), or flawed session management. Mitigation involves applying the Principle of Least Privilege, validating all user input, enforcing multi-factor authentication, and conducting regular security audits.

What is Security Misconfiguration in OWASP 2023 and what does it include?

Security Misconfiguration (#5 on OWASP 2023) covers vulnerabilities arising from incorrect or default configuration settings. It now includes the former XML External Entities (XXE) category from 2017. Common examples include unpatched software, unchanged CMS default settings, exposed unused pages, unprotected files, unnecessary services enabled, and vulnerable XML files. Many attacks are fully automated and exploit default configurations, making it critical to change default settings during installation and tighten access controls, including managing comments, user access, and file permissions.

What is Server-Side Request Forgery (SSRF) and how can it be prevented?

Server-Side Request Forgery (SSRF) is the #10 vulnerability on the OWASP 2023 list. It allows attackers to manipulate a web application into making unauthorized requests from the server to internal or external resources — often without the user’s knowledge. This can expose sensitive data, grant access to internal systems, or fully compromise the application’s infrastructure. Prevention involves validating and sanitizing all user-supplied input, implementing URL whitelisting, configuring firewall rules to restrict outgoing server requests, using safe APIs, and applying the Principle of Least Privilege.

What is the difference between Cryptographic Failures and Sensitive Data Exposure in OWASP?

Cryptographic Failures is the renamed version of “Sensitive Data Exposure” in OWASP 2021 and 2023. The old name described a symptom; the new name identifies the root cause — failures in cryptographic implementation. This includes using weak encryption algorithms, short encryption keys, insecure password storage, weak SSL/TLS protocols, and insufficient transport layer security that can lead to man-in-the-middle attacks. The rename helps developers focus on fixing the cryptographic weaknesses rather than just the resulting data exposure.

What is the difference between Software and Data Integrity Failures and Security Logging and Monitoring Failures in OWASP 2023?

Software and Data Integrity Failures (#8) occur when developers add plugins, libraries, or pipeline dependencies from unverified sources — if any are compromised, they can enable unauthorized data disclosure or malicious code insertion. Security Logging and Monitoring Failures (#9) occur when an application lacks proper logging of login attempts and alerts, allowing breaches to go undetected long enough to cause substantial damage. Both require active inventory management and continuous monitoring: integrity failures need verified third-party components, while logging failures need tamper-protected, backed-up logs with regularly tested monitoring systems.

What is the OWASP Top Ten?

The OWASP Top Ten is a regularly updated list of the 10 most critical web application security vulnerabilities, published by the Open Worldwide Application Security Project (OWASP), a non-profit foundation. OWASP compiles this list using data from over 200,000 organizations combined with surveys of industry professionals. It serves as the industry-standard checklist for web developers, security teams, and anyone responsible for protecting web applications from attack.

What types of attacks fall under Injection in OWASP 2023?

In OWASP 2023, Injection (ranked #3) covers SQL Injection, Cross-Site Scripting (XSS), Command Injection, LDAP Injection, XML Injection, and Server-Side Template Injection (SSTI). These attacks exploit weaknesses in input validation and data handling — attackers inject malicious SQL queries, JavaScript, or system commands into application inputs or URLs to access sensitive data, hijack sessions, or take control of the server.

Why are vulnerable and outdated components dangerous according to OWASP?

Vulnerable and Outdated Components (#6 on OWASP 2023) are dangerous because attackers actively scan for websites using outdated frameworks, libraries, extensions, and plugins with known security flaws. Even a single unpatched dependency can be exploited to spread malware, launch phishing attacks, or compromise the entire system. The recommended mitigation is maintaining a complete, continuously updated inventory of all third-party components — something tools like Reflectiz can automate to keep your website protected.

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