Understanding application security and why it's crucial for businesses

What is application security, and why is it important?

Application security is a set of practices used to increase the security of applications. It covers everything from how apps are designed and built to how they're deployed and maintained.

Why is application security important? Because cybersecurity statistics consistently show that application-layer attacks are among the most common causes of data breaches. As companies integrate more APIs, third-party services, and cloud-based systems, their attack surface keeps growing. Attackers just need one weak spot. From there, they move across different systems, often escalating privileges until they control admin accounts or sensitive infrastructure.

A few essential security practices should span your entire software development lifecycle:

• Introduce application security tools early — during design and development rather than in production.
• Implement security procedures to protect applications in production. For example, continuous security testing helps spot issues before they're exploited.
• Implement application security controls (like rate limiting, role-based permissions, and strong session management), especially where sensitive data is involved.
• Use application security software like firewalls, intrusion prevention systems (IPS), and runtime protections to catch and contain threats in real time.
• Adopt a zero trust architecture that verifies every request and access attempt, ensuring no implicit trust within your application environment.

What are the main types of application security?

Let's look at the main types of modern application security and where organizations need to focus their efforts most.

Web application security

Web applications are software that runs on a web server and can be accessed over the internet. These applications are often critically important for the business, making them a valuable target for cybercriminals.

Mobile application security

Mobile apps introduce a unique challenge: Once they're shipped, developers can't patch the code sitting on users' devices instantly. That makes proactive security essential. Encrypt sensitive data stored on the device, pin TLS certificates to prevent interception, secure your APIs, and carefully vet third-party SDKs, especially ad or analytics libraries, which can introduce privacy and security risks long after release.

API security

API security is critically important for organizations. API security vulnerabilities can cause (and have caused in the past) the most significant data breaches in organizations. Common weaknesses are unwanted exposure of data and weak authentication.

Cloud-native application security

Companies also need to secure their cloud-based platforms, applications, and infrastructure. Cloud-native application security is built in from the software development process to the production environment, granting applications multiple layers of protection.

Common application security vulnerabilities and threats

Modern applications face a wide range of security threats — from poor design decisions to configuration oversights and unpatched code. Attackers routinely exploit these weaknesses to gain unauthorized access, manipulate data, or disrupt services. Security teams work continuously to identify common patterns, reduce risk, and improve defenses across the development lifecycle.

Some frequent and high-impact vulnerabilities include:

• Poor access controls that allow users to act outside their assigned permissions.
• Insecure handling of sensitive data or cryptographic keys.
• Bugs that let untrusted input be executed as code (e.g., injection flaws).
• Overly permissive configurations or exposed infrastructure.
• Use of outdated libraries or software components.
• Weak login systems vulnerable to brute-force attacks or credential stuffing.
• Lack of monitoring, alerting, or integrity checks in deployment pipelines.

To help teams prioritize, industry groups have developed shared frameworks to track and rank these risks — most notably, the OWASP Top 10.

OWASP Top 10 critical risks

The OWASP Top 10 is the industry’s most recognized benchmark for web application security. Curated by the Open Web Application Security Project, it highlights the 10 most critical and recurring vulnerabilities based on real-world exploit data and expert input. The list is updated periodically to reflect emerging attack trends and shifts in how software is built and deployed.

The OWASP Top 10, last updated in 2021, outlines 10 of the most critical security risks facing modern web applications.

1. 1.Broken access control: Failures in enforcing restrictions on authenticated users allow attackers to act outside their intended permissions.
2. 2.Cryptographic failures: Insecure cryptographic practices that can lead to data exposure or manipulation.
3. 3.Injection: Unsanitized input passed into interpreters like SQL, NoSQL, or OS commands can enable attackers to execute arbitrary commands or access unauthorized data. Common examples include SQL injection and command injection.
4. 4.Insecure design: Flaws introduced due to inadequate threat modeling, insecure architecture decisions, or missing controls.
5. 5.Security misconfiguration: Poorly configured systems, default settings, exposed error messages, and mismanaged permissions.
6. 6.Vulnerable and outdated components: Use of libraries, frameworks, or software modules with known vulnerabilities.
7. 7.Identification and authentication failures: Weak or misconfigured login mechanisms can allow attackers to compromise credentials using methods like brute-force attacks, credential stuffing, or session hijacking.
8. 8.Software and data integrity failures: Issues with software updates, CI/CD pipelines, and dependencies that aren't verified for integrity.
9. 9.Security logging and monitoring failures: Lack of visibility into security-relevant events delays incident response.
10. 10.Server-side request forgery (SSRF): Unsanitized user input is used to craft backend HTTP requests, potentially exposing internal systems.

4 main categories of application security testing

Testing turns theory into assurance. Each methodology targets a different stage of the software lifecycle.

1. Static application security testing (SAST)

SAST tools analyze code before it runs, scanning for insecure patterns, hardcoded secrets, or unvalidated inputs. It's one of the earliest lines of defense in the development process. As AI-powered coding assistants like GitHub Copilot become more widely adopted, questions around the security of GitHub Copilot have also surfaced. That's where SAST helps by catching security issues in both human-written and AI-generated code before they go live. 

2. Dynamic application security testing (DAST)

DAST scans the app while it's running. It simulates real-world attacks by throwing malicious inputs at exposed endpoints, looking for issues like reflected XSS or injection flaws. Because it mimics how an attacker sees the app, it tends to produce fewer false positives. The downside is that it only catches what's accessible in the deployed environment.

3. Interactive application security testing (IAST)

IAST sits between SAST and DAST. It uses an agent inside the app to monitor how data flows during live traffic. That means you get real-time, code-level feedback with contextual stack traces, making it easier for developers to fix issues quickly without digging through massive reports.

4. Software composition analysis (SCA)

Modern codebases are 70–90% open source. SCA creates inventories of every dependency, cross-checks versions against vulnerability feeds, and warns when licenses clash with your business model. It's a critical part of application security vulnerability management, especially when third-party code makes up most of your stack.

Tools and techniques that improve application security

Securing applications requires the right mix of tools, processes, and proactive assessment to catch risks early and keep systems hardened over time. Below are best practices and tools that help reduce your exposure to common vulnerabilities.

Application assessment

Application assessments evaluate the security, performance, and compliance posture of software before it's deployed and throughout its lifecycle. They help detect security issues that may otherwise go unnoticed.

Security-focused assessments typically include static and dynamic analysis, penetration testing, and compliance checks based on frameworks like the ones recommended by the National Institute of Standards and Technology (NIST).

Threat assessment

A strong security posture starts with understanding what you're protecting and what you're protecting it from. Threat assessments help you identify sensitive assets, potential entry points, and the methods a hacker can use to gain access or escalate privileges.

Web application firewalls (WAFs)

WAFs sit between your web app and the internet, inspecting incoming traffic and filtering out malicious requests. They help block common web exploits like SQL injection, cross-site scripting (XSS), and bot-driven abuse.

One of their key roles is mitigating tools for DDoS attacks — automated scripts and botnets that flood your servers with fake traffic to take them offline or exhaust system resources. A properly configured WAF can detect these patterns early, rate-limit bad actors, and keep your app available even under stress.

Runtime application self-protection (RASP)

RASP embeds directly into your application and monitors behavior at runtime. If it detects something suspicious (e.g., a rogue eval call or an unexpected file access), it can block the request instantly. Because RASP works with full application context, it's far better at reducing false positives and catching zero-day exploits that signature-based tools may miss.

Vulnerability scanners and SCA tools

Automated scanners test your app from the outside, crawling URLs and checking for known issues. Software composition analysis (SCA) tools do the same under the hood, flagging outdated or vulnerable dependencies in your codebase. Together, they form the foundation of continuous application security assessment and compliance reporting.

Cloud-native application protection platforms (CNAPP)

A CNAPP provides a centralized way to manage the security of cloud-native apps. It combines capabilities from cloud workload protection platforms (CWPP) and cloud security posture management (CSPM), giving teams full visibility.

Integrating with DevSecOps pipelines

Security needs to be embedded in the development pipeline from day one. Integrating SAST, DAST, dependency scanning, and security gates into CI/CD workflows helps teams catch vulnerabilities early and fix them fast. 

Real-world examples and use cases of application security

Application security is what stands between a working product and a breach waiting to happen. Real-world incidents show how critical these practices are:

• Spoutible data breach (2024). An unpatched API endpoint exposed private user messages. A well-defined application security policy requiring regular API testing and vulnerability scans could have flagged the issue before launch.
• Trello misconfiguration (2023). Public boards indexed by search engines exposed project roadmaps and HR discussions. A simple automated scan for open URLs would have caught it on day one.
• Delta Dental of California attack (2024). A credential-stuffing attack on a patient portal led to widespread personal information exposure. After the incident, the company implemented adaptive MFA and rate limiting, led by their internal application security engineer, which significantly reduced unauthorized login attempts.