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Attackers don’t wait until an application goes live to strike. They can do damage during development, in staging environments, and even through third-party dependencies. Application security threats often come from overlooked issues like exposed secrets and outdated libraries that quietly open the door.
Here’s a guide to some common application risks, how they impact your systems, and how to address them with practical, real-world solutions. Whether you’re in charge of or supporting an application security program, this guide explores how to navigate common web application security issues and solutions and stay ahead of attackers.
What Are Application Security Threats?
Application security, or AppSec, focuses on identifying and addressing threats across the entire SDLC. It starts early, shifting security left so teams can spot and resolve issues before the code hits production. The goal is to protect both the code itself and the data it touches. In other words, the data should stay accurate, protected, and accessible, following the CIA triad: confidentiality, integrity, and availability.
Application security threats include any weaknesses attackers can exploit to compromise systems or access sensitive information. These threats affect web apps, but they also appear in mobile apps, APIs, and cloud-native services—anywhere involving third-party code or sensitive data.
Security vulnerabilities often appear through broken authentication, outdated components, or insecure configurations. Some stem from human error, while others take advantage of third-party tools or blind spots between development and security teams. But to avoid these threats, security teams should start with a structured review of their environments and processes. Identifying application security risks early paves a clearer path to fixing them—before they impact users or open the door to more serious issues.
10 Common Web Application Security Threats
Many of the most persistent vulnerabilities appear on the Open Worldwide Application Security Project (OWASP) Top 10, which is a widely recognized list of modern applications' most critical security risks.
Below is OWASP’s list of the most common and high-impact web application threats security teams should have on their radar.
1. Broken Access Control
When access control fails, users can take actions they shouldn’t, like viewing other users’ data or escalating privileges. OWASP reports that over 90% of tested applications have broken access control. It's often the result of missing authorization checks or overly permissive defaults, which quickly lead to information leaks or complete system compromise.
2. Cryptographic Failures
Cryptographic failures happen when encryption is weak, misconfigured, or skipped entirely. This includes errors like storing passwords in plain text or using outdated algorithms. These issues expose sensitive data like financial information, credentials, and personal details.
3. Injection
Injection vulnerabilities like SQL, NoSQL, or command injection allow attackers to send malicious input directly into interpreters. This can result in unauthorized data access or a full system takeover. Many modern web application threats stem from insecure input handling that goes unchecked during development, making these attacks easier to exploit.
While SQL injection still receives considerable attention, cross-site scripting (XSS) remains one of the most common and dangerous injection attacks in web applications. It lets attackers run malicious scripts in users’ browsers, often leading to stolen credentials or session hijacking. These issues usually stem from poor input handling or assumptions about what users can and can’t do with a form field, URL, or request.
4. Insecure Design
Insecure design isn't a bug. It's a blueprint problem. When applications don’t have proper threat modeling, secure design patterns, or architecture reviews, security gaps are present from the start. These flaws often can’t be patched later, meaning security teams may have to overhaul the ways they plan and build systems.
5. Security Misconfiguration
Default credentials, overly verbose error messages, and exposed admin interfaces fall under security misconfiguration. These mistakes are easy to overlook but just as easy for attackers to discover.
Misconfigurations are among the most common cloud security threats in cloud-native environments, especially in open storage buckets, overly permissive identity and access management (IAM) roles, or unprotected Kubernetes dashboards. With more apps relying on configurable infrastructure, the margin for error keeps growing.
6. Vulnerable and Outdated Components
Using components with known vulnerabilities is a ticking time bomb. Whether it’s a library, framework, or plugin, outdated dependencies are one of the fastest paths to exploitation—especially when patches exist but haven’t been applied. Tracking what software depends on is as important as securing the code within it.
7. Identification and Authentication Failures
If identity verification isn’t airtight, attackers will find a way in. Common issues include weak password policies, exposed session IDs, and flawed multi-factor authentication (MFA) implementations. These gaps let attackers impersonate users or hijack sessions.
8. Software and Data Integrity Failures
This category covers risks where systems trust data sources or updates without checking their integrity. For example, insecure CI/CD pipelines, unsigned software updates, or deserialization of untrusted data allow attackers to manipulate workflows or inject malicious code.
9. Security Logging and Monitoring Failures
Without proper logging and alerting, even obvious attacks go undetected. Many breaches aren’t discovered for weeks or months—not because attackers were stealthy, but because no one was watching. Logging only works if security teams do so consistently, monitor actively, and cover the right events.
10. Server-Side Request Forgery
Server-side request forgery (SSRF) lets attackers make the application send requests to unintended destinations—often internal services that aren’t meant to be exposed. A successful SSRF exploit can lead to sensitive data exposure, privilege escalation, or even pivoting into other systems behind the firewall.
Best Practices to Avoid Application Security Threats
Security shouldn’t rely on just one layer of defense. These best practices reduce risk at every stage—from development through deployment—by preventing the most common vulnerabilities from creeping into your applications.
1. Execute Input Validation
Always treat user input as untrusted. Validating incoming data's type, length, and format prevents injection attacks and other unintended behavior. This step also supports a strong application security risk assessment checklist and keeps unexpected behavior out of an app’s core logic.
2. Follow Secure Coding Standards
Consistent, security-first coding patterns reduce the likelihood of introducing vulnerabilities. Avoid unsafe functions, use parameterized queries, and document edge cases. This maintains code quality while reducing the risks that stem from third-party dependencies or custom-built components.
3. Use Up-to-Date Encryption
Encrypt all sensitive data—whether in transit, at rest, or in use—with modern best practices. These practices often include strong cipher suites, up-to-date transport layer security (TLS) configurations, and secure password hashing algorithms.
Keeping encryption current supports cloud application security best practices, especially in environments where misconfigurations and exposed credentials are common risks.
4. Automate and Integrate Testing
Application security testing offers the visibility to fix issues before they create real risk. Running an application early often helps uncover hidden vulnerabilities in business logic, misconfigured APIs, and third-party dependencies.
This approach addresses common security threats that are harder to catch without automated, ongoing testing. It also strengthens your ability to deal with broader threats. From insecure authentication flows to outdated components and misconfigurations, testing uncovers patterns that often lead to serious security issues on the web.
With modern applications depending on external libraries and services, testing also helps reduce software supply chain security risks that can quietly creep in during development. By maximizing application security testing, you gain a faster, more scalable way to improve your security posture.
Address Application Security Threats With Legit Security
Application security threats can emerge at any stage of the software development lifecycle, from initial code commits to build pipelines and deployment. Legit Security helps you quickly catch and respond to these risks by integrating directly into your teams' tools.
Legit Security provides clear visibility into your software supply chain, tracks security posture across environments, and prioritizes what matters most so you can stay focused and confidently deliver secure software. Request a demo today.