Software Testing & Security Testing 2025: Building Reliable and Secure Applications

• Security testing ensures software is protected against real-world attacks it finds and fixes vulnerabilities before they’re exploited.
• Unlike functional testing does it work?, it asks can it be broken? ,validating confidentiality, integrity, and availability.
• Core methods include SAST, DAST, IAST, SCA, and penetration testing.
• DevSecOps shift-left integrates automated scans and manual reviews early in development, catching flaws sooner and cheaper.
• In 2025, with average breach costs hitting $4.88M IBM and attackers growing more advanced, proactive testing is non-negotiable.
• Benefits: protects data and reputation, ensures compliance PCI, HIPAA, NIST, and delivers strong ROI by preventing costly breaches.

What is Security Testing vs Functional Testing?

Security testing examines software with an attacker’s perspective, trying unexpected or malicious inputs to reveal vulnerabilities, weak authentication, misconfigurations, injection flaws, etc.. This contrasts with normal functional testing, which checks features work for honest users e.g. can the user complete this task?. In short, functional tests verify correctness does the login work?, while security tests ask can an attacker break it?. Code Intelligence notes that security testing is a form of non functional testing it validates how the system handles malicious or unexpected scenarios. For example, a login form may pass functional tests but still be vulnerable to SQL injection or session hijacking, which only security tests catch.

By design, security testing assumes an adversary. NIST defines penetration testing a form of security testing as security testing in which assessors mimic real world attacks to identify methods for circumventing the security features of an application, system, or network. Security tests target the CIA triad Confidentiality, Integrity, Availability rather than just user facing requirements. This helps organizations protect sensitive data and prevent breaches. As one expert puts it: Security testing is essential for software that processes confidential data to prevent system intrusion by attackers.

Because security testing goes beyond typical QA, it complements functional testing. Both are needed: functional tests ensure features work as expected, and security tests ensure those features can’t be abused. In modern DevSecOps, teams shift left by automating both types of tests early in development.

Why Security Testing Matters in 2025

The stakes of security testing have never been higher. Cyberattacks are skyrocketing in scope and cost. IBM reports the average data breach cost reached $4.88 million in 2024, a record high, and global cybercrime damage is projected to top $10 trillion by 2025. Ransomware and data breaches hit a record number of organizations in 2023. Small and medium businesses are especially vulnerable: about 60% of SMBs now list cyber risk phishing, ransomware, etc. as a top concern. In short, no one is immune to cyberthreats, and reactive fixes post breach are very expensive.

Proactive security testing helps prevent or mitigate these issues. By finding bugs and misconfigurations before attackers do, organizations save money and reputational damage. Studies consistently show catching a security defect early during development or testing is far cheaper than after release or breach. For example, one industry analysis notes that a critical flaw is orders of magnitude more expensive to fix once exploited or in production often 10- 100x the cost.

Regulations and standards also drive demand for security testing. Frameworks like PCI DSS, ISO 27001, HIPAA, NIST’s SSDF, and others explicitly require regular penetration tests and vulnerability assessments. For instance, PCI DSS mandates yearly or after major change pen tests Requirement 11.3, and NIST guidelines encourage continuous automated analysis. Integrating security tests ensures compliance and avoids fines or audit failures.

Finally, real breaches underscore the need. Major companies like Adobe, Sony, and even nation wide services have been compromised through simple security oversights. Post incident, these organizations doubled down on security testing e.g. regular pentests, automated scanning to regain trust and harden their defenses. Today’s interconnected apps cloud, APIs, mobile expand the attack surface. Security testing uncovers hidden risks from broken access controls to insecure APIs so teams can fix them before attackers do.

Key Security Testing Methods SAST, DAST, Pen Testing, and More

Security testing encompasses a variety of techniques, each with a different focus. The most common methods include:

• Static Application Security Testing SAST Analyzes source code or binaries to find vulnerabilities before running the app. SAST tools scan code for patterns like SQL injection, XSS, hard coded secrets, insecure crypto, etc.. They run at shift left stages in IDE or CI builds and can cover 100% of code paths. Pros: Finds code issues early cheaper to fix, integrates with dev tools. Cons: Generates false positives; misses runtime issues or environment specific flaws e.g. auth misconfigurations. Example tools: Checkmarx, SonarQube, Fortify, CodeQL.
• Dynamic Application Security Testing DAST Tests the running application black box by sending malicious payloads e.g. SQLi, XSS, CSRF attacks and inspecting responses. DAST simulates an external attacker probing your live app. It catches issues that only appear at runtime, such as authentication/authorization gaps, insecure server settings, and logic flaws. Pros: No source code needed, finds real attack paths with fewer false positives. Cons: Can only test exposed endpoints hidden code paths stay unchecked and is slower; typically done in QA/staging fixes may be costlier later. Example tools: OWASP ZAP, Burp Suite, Acunetix.
• Interactive Application Security Testing IAST A hybrid that instruments the app often via an agent in test environment to combine static and dynamic analysis. IAST tools monitor running code to pinpoint vulnerabilities with context, yielding more accurate results than SAST/DAST alone. Think of it as real time, in app testing.
• Software Composition Analysis SCA Scans open source libraries and dependencies for known CVEs and license issues. Since many breaches exploit third party components, SCA keeps track of outdated packages and automatically flags library vulnerabilities.
• Vulnerability Scanning Automated tools scan systems, networks, or applications for known vulnerabilities using CVE databases. These are broad, high level checks e.g. Nessus, Qualys that list potential weak points like unpatched software or default credentials. Pros: Fast, safe to run regularly, covers large environments. Cons: High false positive rate; it only detects known issues and does not prove exploitability or find complex logic flaws.
• Penetration Testing Pentest Manual, ethical hacking that actively exploits vulnerabilities to show real world impact. Skilled testers internal red teams or external firms mimic attackers using all available info and tools. OWASP notes: A penetration tester plays the role of the attacker to find and exploit vulnerabilities, providing a more accurate risk picture than scans alone. Pentests can target networks, applications, cloud, or user social engineering. Typical pentest phases include planning, discovery scanning, exploitation, and reporting per NIST SP 800 115. Pros: Finds complex, chained vulnerabilities and business logic flaws. Cons: Labor intensive, usually scoped and periodic not continuous, and requires expertise.

For example, SAST can catch a hard coded database password or missing input sanitization in code, while DAST would catch a misconfigured login page or missing HTTP security headers during runtime. A penetration test might chain several minor issues weak admin password + outdated software + missing patches to demonstrate a full breach that automated tools alone missed.

It’s important to mix methods. OWASP advises adding security tests throughout the pipeline: use SAST/SCA in CI, run DAST against test deployments, and schedule manual pentests or bug bounties periodically. This layered approach ensures fewer gaps.

Common Misconceptions Myth vs Fact

• Myth: Functional testing covers security. Fact: No functional tests assume honest usage and won’t reveal malicious exploits. Security testing is distinct. As CodeInt explains, Security testing is a form of non functional testing focusing on unexpected/malicious inputs. Functional tests may never hit paths that an attacker would.
• Myth: One pentest is enough. Fact: Threats change constantly. A single pen test only shows a snapshot. New code, new vulnerabilities, or new attacker techniques emerge all the time. NIST and DevSecOps best practices recommend continuous testing: e.g. automated scans on each build plus periodic pen tests.
• Myth: Automated tools alone suffice. Fact: Automated scanners SAST, DAST, vulnerability scans catch many issues but miss complex logic flaws or zero day attacks. Manual review/pen testers find the creative exploits. The best programs combine both.
• Myth: Only large enterprises get attacked. Fact: Hackers target any vulnerable system. IBM notes 60% of SMBs now consider cyber threats a top risk. Nearly half of breaches hit small companies. Security testing is vital for businesses of all sizes to avoid being easy prey.
• Myth: Security testing is too expensive. Fact: Skipping it is far more costly. A single breach cost millions. IBM says $4.88M on average. Proactive testing, especially automated tools can save orders of magnitude more by preventing just one serious incident.

Integrating Security Testing in DevOps How To

A robust software process includes security at every step. Here’s a step by step guide to embedding security testing in your SDLC:

1. Plan and Scope Early: Define which assets need testing web apps, APIs, mobile apps, network, etc.. Identify compliance requirements PCI, HIPAA, etc. upfront, as these often dictate test types.
2. Shift Left Security: Integrate security tools in your CI/CD pipeline. For example:
   • Code Commit: Run SAST and secret scanners on each pull request, giving instant feedback to devs.
   • Build Time: Use Software Composition Analysis SCA to check for vulnerable libraries. Also run unit/integration tests.
   • Deploy/Release: Run DAST/IAST against your staging deployment to catch misconfigurations and runtime issues.
3. Continuous Monitoring: Implement automated vulnerability scans e.g. weekly Nessus scans of production servers. Use a vulnerability management tool to track findings.
4. Penetration Testing: Schedule a formal pentest by qualified ethical hackers at least annually and before major releases. Ensure testers have clear rules of engagement scope, targets, time as per NIST SP 800 115 guidelines. Both internal and external tests are valuable see below.
5. Code Reviews & Threat Modeling: Incorporate peer code reviews focusing on security. Do threat modeling for new features identify where data flows can be attacked.
6. Fix & Verify: Triage findings by risk, fix high impact issues first. Verify fixes with re testing. Maintain an audit trail of tests and fixes. Use dashboards or issue tracking to ensure nothing falls through.

Checklist:

• Run SAST e.g. SonarQube on every commit.
• Scan open source components Snyk, Dependabot.
• Run DAST e.g. ZAP nightly or per sprint on a staging environment.
• Perform manual pentests on critical assets web apps, APIs, network perimeter.
• Use container/image scanning Trivy for Docker/Kubernetes security.
• Ensure red team or bug bounty programs complement automated tests.

By making security testing a habit not a one off, teams catch vulnerabilities early and build more secure software with less firefighting later.

Internal vs External Penetration Testing

Penetration tests come in two flavors:

• External Pentesting: Focuses on the public facing perimeter. It simulates an attacker from the Internet trying to break in. Targets include web applications, firewalls, VPNs, email servers, and exposed cloud endpoints. Think someone knocking on your digital front door. External tests answer Can attackers break in from outside?.
• Internal Pentesting: Assumes the attacker already breached the outer defenses via phishing, stolen creds, or insider threat and explores the internal network. It checks lateral movement, privilege escalation, and access to sensitive data inside the company. In other words, someone’s inside your house, what can they do next? Internal tests protect against insider threats and misconfigured internal controls.

Both are essential. OWASP summarizes: External pentests tell you if bad guys can get in. Internal pentests show you how bad it could get if they do.. Together, they give a full picture of your security posture.

For example, DeepStrike’s guide on internal vs external testing notes that internal testing reveals issues like weak user privileges or file share access, while external testing finds open ports and vulnerable web apps. The schedule often includes an annual external pentest and an internal pentest sometimes mid year but needs vary by business.

Key Statistics & ROI

• Breach Costs: IBM’s 2024 report found the average breach cost is now $4.88M globally up 10% from 2023. In the U.S., breaches can average over $10M. Investing in security testing especially before release dramatically reduces this risk.
• Vulnerability Growth: Over 30,000 new software vulnerabilities were cataloged in 2024 17% more than 2023. Verizon found breaches via exploited vulnerabilities surged 180% year over year. This flood of new CVEs means continuous scanning and patching is mandatory.
• Security Testing Adoption: A 2023 industry survey reports 40% of organizations run automated security tests on 70% or more of their code. As Pentesting as a Service PTaaS grows, more companies pay for ongoing pen test engagements. The global pentest market is projected to exceed $5B by 2031.
• Phishing & ATO: Account takeover ATO attacks have been rising. One notable case the HubSpot bug bounty ATO highlighted how a single chained exploit could give full account control, emphasizing the need to test authentication flows see account takeover case study.
• ROI of Early Testing: Estimates show fixing a security bug during development can be 6- 15 times cheaper than patching it post release. In one example, a trading glitch at Knight Capital 2012 due to a test error cost $440M in 30 minutes, illustrating the cost of poor testing.

Overall, spending on security testing tools and services is a fraction of the potential loss from breaches. Gartner projects global security spending to grow 15% in 2025 organizations are prioritizing this investment.

Tools and Resources

There are many tools to automate and aid security testing at different stages:

• SAST Tools: SonarQube, Checkmarx, Veracode, GitHub CodeQL, Bandit Python, etc. These integrate into IDEs/CI to catch code flaws.
• DAST Tools: OWASP ZAP, Burp Suite, Acunetix, Netsparker, Rapid7 AppSpider, etc. They scan running web apps and APIs for vulnerabilities.
• SCA Tools: Snyk, Dependabot, Black Duck, WhiteSource for open source dependency scanning.
• Vuln Scanners: Nessus, Qualys, OpenVAS for network/system scanning.
• Pentest Utilities: Metasploit, Nmap, custom exploit scripts, and proxy tools Burp, ZAP for manual testing. Even general dev tools like Postman for API fuzzing can be repurposed.

For guided processes, the NIST SP 800 115 provides methodology for planning/executing security tests. OWASP’s documentation Top 10, Testing Guide, DevSecOps guideline and CISA’s resources offer up to date attack examples and best practices.

Lastly, keep an eye on credible industry reports: IBM’s annual Cost of a Breach, Verizon’s DBIR, OWASP Top 10, etc., for trending threats to focus your testing on.

Security testing ensures your software not only works, but survives real world attacks. By weaving security tests into every phase of development from code commit static scans to deployment dynamic scans to pre release pentests you catch vulnerabilities early, save costs, and build trust. The threats of 2025 demand more than just awareness; they require readiness.

Ready to strengthen your defenses? DeepStrike’s team of security practitioners can uncover hidden risks before attackers do.

Explore our penetration testing services and related solutions. Whether you need a one time audit or continuous testing, we help you validate your security posture and implement a resilient defense strategy. Drop us a line we’re always ready to dive in.

About the Author: Mohammed Khalil is a Cybersecurity Architect at DeepStrike, specializing in advanced penetration testing and offensive security operations. With certifications including CISSP, OSCP, and OSWE, he has led numerous red team engagements for Fortune 500 companies, focusing on cloud security, application vulnerabilities, and adversary emulation. His work involves dissecting complex attack chains and developing resilient defense strategies for clients in the finance, healthcare, and technology sectors.

FAQ

• What is security testing?

Security testing is the practice of evaluating software for vulnerabilities by simulating attacks or malicious inputs. It focuses on the software’s confidentiality, integrity, and availability. Unlike functional testing which assumes honest users, security testing assumes attackers might misuse the system. Tests include code analysis, dynamic scans, and penetration testing to ensure the system can withstand cyber threats.

• How does security testing differ from regular software testing?

Regular functional testing checks if features work as intended for end users e.g. does login accept valid credentials?. Security testing, on the other hand, checks for weaknesses an attacker could exploit e.g. can an attacker bypass login or inject a payload?. In other words, functional testing asks Does it do what it should? ; security testing asks Can someone make it do something it shouldn’t?.

• What are common types of security testing methods?

Key methods include SAST static analysis of code, DAST dynamic scans of live apps, IAST combined interactive analysis, SCA scanning open source dependencies, and penentration testing manual ethical hacking. Each method covers different layers for example, SAST finds code errors early, while DAST catches runtime issues like misconfigurations. A comprehensive program uses multiple methods together.

• When should security testing be done?

Ideally, security testing is continuous. Integrate tests into every stage: run static and SCA scans on code commits and builds; run dynamic scans on each deployment; and schedule manual penetration tests regularly e.g. annually or before major releases. The earlier you catch vulnerabilities e.g. during development, the cheaper and easier they are to fix.

• Do I need both vulnerability scans and penetration tests?

Yes. Vulnerability scanning automated and penetration testing manual serve complementary roles. Scanning provides broad coverage to flag known issues, while pentesting actually exploits them to show real risk. As DeepStrike explains in its Vulnerability Assessment vs Penetration Testing guide, combined, they provide full coverage: automated scans for visibility and manual tests for validation.

• What skills are needed for security testing?

Security testing often requires specialized skills. SAST/DAST tools can be used by developers or QA with training, but effective pentesting usually needs experienced security professionals, penetration testers, red teamers. These experts know common attack techniques, networking, cryptography, etc. Certification OSCP, CEH, CISSP is common. Many organizations augment their QA teams with security experts or outsource pentesting to specialists.

• Can we automate security testing entirely?

Automation can handle many routine checks SAST, DAST, SCA, container scans. However, automated tools have limits they may miss complex logic flaws or chain vulnerabilities. Manual assessment or skilled pentesters are still needed to creatively probe business logic, social engineering, and complex exploits. The best practice is automated plus manual testing for critical systems.