Security Scanning vs. Penetration Testing in CI/CD

When it comes to securing CI/CD pipelines, two methods stand out: security scanning and penetration testing. Both play unique roles in identifying and addressing vulnerabilities, but they differ in execution, scope, and frequency.

• Security scanning is automated, continuous, and focuses on detecting known vulnerabilities using tools like DAST, dependency, or container scanners. It's fast, scalable, and perfect for regular checks during development.
• Penetration testing, on the other hand, is manual or semi-automated. It simulates attacks to find deeper or complex vulnerabilities that scanners might miss, such as flaws in business logic or chained exploits. It's often conducted quarterly or annually.

Key takeaway: Use both methods together. Security scanning ensures ongoing checks, while penetration testing provides deeper validation of your defences. This dual approach strengthens your pipeline's security without slowing down deployments.

Quick Comparison

What is Security Scanning?

Security Scanning Defined

Security scanning is an automated process that uses specialised tools to identify security weaknesses, configuration errors, and vulnerabilities in systems, networks, and applications[2][3]. These tools work by comparing the target environment to databases of known vulnerabilities, such as CVEs (Common Vulnerabilities and Exposures)[2].

Here’s how it works: scanners send requests to a predefined scope - like a URL, web application, or IP range - and analyse the responses for details such as version numbers, protocols, and default configurations[5]. If a scanner detects a version or configuration linked to a known vulnerability, it flags it for remediation[5].

Security scanning is particularly valuable in CI/CD pipelines because it provides continuous, automated checks without disrupting development workflows. These tools can run automatically at various stages - from code commits to deployment - ensuring regular security validation without manual input[2]. This automated approach is essential for maintaining security in fast-paced CI/CD cycles, making it a perfect fit for DevSecOps practices and agile environments.

Scanning tools also provide a dual perspective by examining systems both externally and internally. External scans assess the security of internet-facing systems like web servers and public applications, while internal scans focus on devices within an organisation’s internal network[3]. This comprehensive approach can even uncover vulnerable shadow IT devices that might not be under IT’s direct control[3].

Now, let’s dive into the main types of security scanning used in CI/CD environments.

Types of Security Scanning

Security scanning includes several methods, each targeting specific aspects of application security within CI/CD pipelines.

• DAST (Dynamic Application Security Testing): These scanners simulate attacks on live applications, mimicking real-world attackers[2]. Instead of checking static code, DAST tools focus on vulnerabilities in running software. They evaluate how systems respond to malicious or malformed inputs, making them particularly effective for spotting insecure configurations and injection vulnerabilities[5].

• Dependency Scanning: Modern applications often rely on dozens - or even hundreds - of third-party libraries or open-source components. Dependency scanning identifies vulnerabilities in these external dependencies by comparing library versions against vulnerability databases, alerting teams about outdated or compromised packages.

• Container Security Scanning: With containers playing a central role in CI/CD workflows, this scanning type examines the security of container images, layers, and configurations. These tools analyse operating system packages inside containers and the configurations of orchestration platforms to ensure the infrastructure is secure.

• Vulnerability Scanning: Offering broader coverage, these tools look for both known and unknown vulnerabilities across the entire technology stack. They generate large volumes of requests in a short time, checking for missing patches, insecure setups, and other security flaws[3][5].

Benefits and Drawbacks of Security Scanning

Security scanning provides several advantages for CI/CD environments, but it also has its limitations.

Advantages:

• Speed and Efficiency: Automated scanners can cover large portions of your infrastructure far faster than manual testing, making frequent scans both practical and cost-effective[2]. This allows organisations to schedule scans daily or weekly[2].

• Wide Coverage: Scanning tools can assess a broad range of systems and applications, offering a solid overview of your security posture[3]. This ensures that vulnerabilities are less likely to be overlooked during rapid development cycles.

• Reduced False Positives: Many tools now include auto-validation features to minimise false positives, helping teams focus on genuine risks. Results often include CVSS severity scores, allowing organisations to prioritise remediation efforts based on factors like impact and exploitability[3].

Drawbacks:

• Point-in-Time Limitations: Scans only provide a snapshot of your security at the time they’re run. If a new vulnerability emerges after a scan, it won’t be detected until the next scheduled scan[3]. Continuous scanning is essential to maintain up-to-date security awareness.

• Low Context Awareness: Scanners rely on known patterns and behaviours, so they can’t identify complex attack chains or business logic flaws that require human insight[2][4].

• Missed Vulnerabilities in Unauthenticated Scans: Scans without privileged access may miss deeper vulnerabilities. Some flagged issues might not be exploitable, especially if mitigated by controls like firewalls or network segmentation[3].

• Data Overload: Scanning generates extensive reports that require careful analysis. Without proper tools and processes, teams can struggle to prioritise and address the most critical issues from the noise[5].

What is Penetration Testing?

Penetration Testing Defined

Penetration testing involves ethical hackers simulating attacks to identify security weaknesses in systems, applications, APIs, or networks [2]. Unlike automated vulnerability scanners that rely on databases of known issues, penetration testing focuses on exploiting vulnerabilities to assess how they could be used in an actual attack [2].

The key difference lies in the method. Vulnerability scanners highlight potential risks based on patterns, while penetration testers actively attempt to bypass defences using tools and techniques similar to those of malicious hackers [3]. This hands-on approach evaluates how well security measures hold up against real-world threats, uncovering flaws in business logic and risks that automated tools often overlook [2].

This process requires skilled professionals who combine technical expertise with creative problem-solving. These testers think beyond standard approaches, exploring various attack methods to breach systems [4]. Importantly, penetration tests are always conducted with proper authorisation to ensure legal compliance and prevent disruptions to regular operations [3].

While automated tools play a role in identifying common vulnerabilities, the bulk of penetration testing - about 90% - relies on manual analysis. Testers dig deep into the environment, simulating realistic attack scenarios to exploit weaknesses. This blend of automation and human insight provides a more nuanced understanding of security gaps.

Types of Penetration Testing in CI/CD

In the context of CI/CD, penetration testing can take several forms, each tailored to specific needs.

• Full penetration tests: These involve comprehensive, manual assessments of entire systems or applications. Testers simulate detailed attack scenarios, often combining multiple vulnerabilities or misconfigurations to uncover critical security risks [4]. This approach offers a thorough review of your security architecture.

• Targeted penetration tests: These focus on specific areas, such as cloud infrastructure, web applications, or internal networks. By narrowing the scope, these tests address high-risk components, making them particularly effective in fast-moving CI/CD environments [5].

• Compliance-driven penetration testing: Designed to meet regulatory requirements, these tests are often mandated by standards like PCI DSS, which requires both internal and external testing annually or after significant changes [3]. Other frameworks, including NIST 800-53 and ISO/IEC 27001, also recommend penetration testing as a core security practice [3].

• Semi-automated penetration testing: This method combines automated tools with human expertise, enabling faster validation of security controls while retaining the depth of manual analysis [2]. It’s a practical choice for CI/CD pipelines, balancing speed with thoroughness.

Benefits and Drawbacks of Penetration Testing

Penetration testing offers valuable insights for CI/CD security but comes with its own set of challenges.

Advantages:

• It provides a realistic view of attack paths, showing the actual damage potential rather than just identifying theoretical vulnerabilities [2]. By simulating real attacks, penetration testing reveals true risk exposure.

• Testers bring a contextual understanding that uncovers complex vulnerabilities missed by automated tools [4]. For instance, they can identify how seemingly minor issues might combine into a major security breach.

• False positives are reduced, saving time and resources. Skilled professionals verify vulnerabilities to ensure they’re genuine risks, eliminating distractions caused by harmless issues flagged by scanners [3].

• It validates the effectiveness of security measures like network segmentation or web application firewalls. Penetration testers can uncover vulnerabilities that require deeper access or specific system knowledge, which automated scans might overlook [3].

Drawbacks:

• Cost is a major hurdle. Penetration testing is significantly more expensive than automated scanning due to the expertise and time required for manual analysis [2].

• Time constraints make it less suitable for continuous workflows. Unlike vulnerability scans that can run daily, penetration tests are typically conducted quarterly or annually, which may not align with the fast pace of CI/CD deployments [2, 8].

• Scalability is limited compared to automated tools. Penetration testing can’t cover as many systems or applications, making it impractical as the sole security measure in dynamic environments [2].

• Skill dependency is another challenge. Penetration testing requires highly experienced professionals, which can be difficult for some organisations to source, potentially leading to bottlenecks [2].

Despite these challenges, penetration testing, when combined with automated scanning, forms a robust, multi-layered defence strategy for securing CI/CD pipelines. It bridges the gap between theoretical risk identification and real-world attack resilience.

What A Vulnerability Scan Does: Guide To Pen Testing - Part 3

Security Scanning vs. Penetration Testing

Effective CI/CD security relies on a smart combination of automated security scanning and targeted penetration testing. Together, they help strike a balance between cost-effectiveness and risk management.

Comparison Table

How Each Works

Security scanning is powered by automated tools that continuously compare your systems against updated vulnerability databases like CVE lists [2]. This automation makes scanning a cost-effective and scalable option. It can run on a continuous or scheduled basis, flagging issues like outdated software, missing patches, or configuration errors without requiring manual input.

On the other hand, penetration testing involves security experts actively simulating attacks to exploit vulnerabilities [2]. Unlike scanning, which identifies potential risks, penetration testing evaluates their real-world impact. For example, it determines if a flagged vulnerability could actually be exploited or if existing controls, like firewalls, already mitigate the risk [3].

While scanning provides a broad overview of vulnerabilities, penetration testing dives deeper. Scanners might generate false positives due to their limited context, but penetration testers validate these findings, providing a clearer picture of your security posture.

When to Use Each Method

The choice between security scanning and penetration testing depends on the stage of development and the specific security goals.

• Security scanning is ideal during the early phases of development and integration. Automated scans can run on every code commit in your CI/CD pipeline, quickly identifying issues like missing patches or misconfigurations [1]. This approach ensures developers can address vulnerabilities before they escalate. Scanning also detects shadow IT devices - systems operating outside IT's control - offering a baseline view of your infrastructure's security [3]. For comprehensive results, it's recommended to run both authenticated and unauthenticated scans, as the latter might miss vulnerabilities requiring privileged access.

• Penetration testing, on the other hand, is crucial before production deployment or significant updates. For example, launching a new payment system or implementing major infrastructure changes calls for penetration testing to simulate real-world attacks and verify security controls [2]. This is not just a best practice but often a regulatory requirement. Standards like PCI DSS mandate annual penetration tests and additional tests after significant changes [3]. In high-risk environments, such as those handling sensitive data or financial transactions, penetration testing uncovers weaknesses that automated scans might miss.

Additionally, penetration testing helps validate the findings from automated scans. For instance, while a scanner might flag outdated software libraries, a penetration tester determines whether these pose a genuine risk or are mitigated by existing controls [3].

Combining Both Approaches

The best security strategy integrates both methods. Automated scanning offers continuous, broad coverage, while penetration testing provides periodic, in-depth assessments. For example:

• A UK-based e-commerce platform could run automated scans on every pull request to catch known issues early.
• Before each quarterly release, penetration tests could verify that security measures are effective and uncover hidden vulnerabilities, such as business logic flaws.

Interestingly, vulnerability scanning often forms about 10% of a penetration testing process, serving as the reconnaissance phase that guides manual analysis [5].

At Hokstad Consulting, we recommend a layered approach to security. Combining continuous scanning with periodic penetration testing ensures robust CI/CD security while meeting regulatory requirements. This balance keeps your systems resilient against evolving threats and provides peace of mind for your organisation.

Combining Both Methods

Effective CI/CD security combines automated scanning and penetration testing to create a well-rounded defence strategy. Each method addresses unique security needs at different stages of your pipeline, forming the backbone of a layered approach to security.

Building a Layered Security Strategy

A layered security strategy uses automated scanning as the first line of defence and penetration testing as the validation layer. Automated scanning continuously identifies vulnerabilities using up-to-date CVE data[2]. This is crucial for DevSecOps pipelines and agile environments, where rapid deployments demand constant security checks.

Penetration testing complements this by simulating real-world attacks, typically on a quarterly or annual basis. It goes beyond identifying vulnerabilities to assess whether they can actually be exploited in your environment[2]. Automated scans catch known issues and misconfigurations in real time, while penetration testers focus on more complex areas like business logic, workflows, and attack chains that automated tools might overlook[2].

Automated tools scan your IT environment - covering servers, endpoints, databases, and network devices - from both internal and external perspectives[3]. These tools generate reports with CVSS scores to help prioritise fixes[3].

On the other hand, penetration testing digs deeper. While scans flag potential problems, penetration testers explore whether these issues can truly be exploited[2]. This human-driven process often begins with vulnerability scans to guide their testing, but it adds a critical layer of depth by identifying attack paths and exploitation scenarios that machines can't detect[2].

For bridging the gap between these methods, Dynamic Application Security Testing (DAST) is a powerful option. It validates real, exploitable risks, ensuring that both automated and manual efforts focus on the most pressing threats[2].

Best Practices for Using Both Methods

To make the most of automated scanning and penetration testing, thoughtful planning is key. Here are some best practices to ensure these methods work together effectively:

• Integrate scanning into your CI/CD pipeline: Embedding vulnerability scanning into CI/CD workflows ensures daily security checks. These tools can scan code commits, dependencies, and infrastructure configurations before they progress through the pipeline[2].

• Schedule penetration testing strategically: Since penetration testing is more time-intensive and costly, it’s typically done quarterly or annually. For high-risk systems or sensitive data, more frequent testing may be necessary. Regulatory frameworks like PCI DSS mandate such tests at least annually and after significant system changes[3].

• Use scan results to guide penetration testing: Vulnerability scan reports can help penetration testers focus on critical and exploitable issues. This allows for more targeted and effective testing efforts[5].

• Establish feedback loops between methods: When penetration testers find vulnerabilities that automated scanners missed, this information should be used to improve scanning tools and detection rules. Similarly, if testers confirm that flagged issues are non-exploitable, this insight can refine your risk prioritisation process and reduce unnecessary alerts[1][3].

• Prioritise remediation based on exploitability: Automated scans provide CVSS scores as a baseline for severity. Penetration testing adds context by confirming which vulnerabilities are exploitable and assessing their potential business impact. Focus on vulnerabilities that are both high-severity and exploitable, while considering compensating controls like network segmentation for lower-priority issues[2][3].

• Minimise false positives: Automated scanners often flag harmless issues as vulnerabilities. Penetration testers help validate these findings, ensuring that security teams spend their time on genuine risks rather than chasing false alarms[3].

• Define clear severity thresholds: Escalate only critical and high-severity vulnerabilities for immediate action, while scheduling medium and low-severity issues for regular remediation cycles. This approach prevents alert fatigue and keeps teams focused on real threats.

At Hokstad Consulting, we specialise in helping organisations implement layered security strategies. By integrating automated scanning into CI/CD pipelines and scheduling targeted penetration tests, we ensure that both methods work together seamlessly. This balanced approach strengthens your defences, meets compliance requirements, and keeps costs under control - all while adapting to evolving threats.

Conclusion

Security scanning and penetration testing work hand in hand: scanning provides ongoing, automated alerts for known vulnerabilities, while penetration testing offers deeper, periodic validation through realistic attack simulations [1][2]. Together, they create a balanced approach that informs smarter deployment strategies.

The secret to securing CI/CD pipelines lies in understanding when and how to use each method. Automated scanning integrates seamlessly into deployment workflows, offering instant feedback - perfect for fast-paced DevSecOps environments [2]. On the other hand, penetration testing verifies whether flagged vulnerabilities are genuinely exploitable and identifies attack paths that automated tools might miss [1][2]. To maximise its effectiveness, schedule penetration tests strategically - at least once a year to meet PCI DSS compliance and after major infrastructure or application updates [3].

Incorporating vulnerability scanning directly into CI/CD pipelines ensures continuous security hygiene, catching issues before they reach production. While scanning can sometimes produce false positives and penetration testing won't catch vulnerabilities between testing cycles, combining the two significantly strengthens your defences [2][3].

To secure CI/CD pipelines without slowing deployment, organisations must embrace both methods. By automating routine vulnerability checks and reserving manual penetration testing for high-risk areas and compliance needs, you can create a security strategy that protects your applications while keeping development workflows efficient [1][2]. At Hokstad Consulting, we champion this layered approach as a reliable way to achieve strong security without compromising deployment speed. It’s a practical application of the principles discussed throughout this guide.

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