Container Vulnerability Scanning: Technologies & Best Practices

What Is Container Vulnerability Scanning? 

Container vulnerability scanning is the process of identifying security weaknesses in container images and running containers. It helps detect vulnerabilities like outdated packages, misconfigurations, and known security flaws before they can be exploited. This process is crucial for ensuring the security and integrity of containerized applications. 

Container scanning typically inspects components such as operating system packages, libraries, and application dependencies by comparing them against vulnerability databases like the National Vulnerability Database (NVD) and vendor advisories. Container scanning tools integrate into development and deployment workflows. They can be invoked during image builds, in CI/CD pipelines, or continuously on running containers to catch vulnerabilities as soon as they appear.

Container vulnerability scanning is a critical part of modern cybersecurity strategies. It enables early vulnerability detection, reduces risk in containerized applications, improves the organization’s security posture, and enables compliance for critical applications that rely on container technology. 

This is part of a series of articles about container security.

Why Is Container Vulnerability Scanning Important? 

There are several reasons that organizations should ensure regular scanning of containers for vulnerabilities.

Early Vulnerability Detection

Catching vulnerabilities early in the development lifecycle reduces remediation costs and the risk of deploying insecure code to production. Vulnerability scanning tools integrated in CI/CD pipelines help ensure that images with known issues are flagged before they reach registries or runtime environments. By identifying potential threats during builds, organizations can enforce security standards consistently and at scale.

Early detection also empowers developers to fix vulnerabilities in upstream dependencies or adjust build processes before business operations or customers are exposed to risk. This proactive approach shortens feedback loops and enables teams to adopt a security-first mindset, ultimately building more secure applications as part of their delivery workflows.

Reduced Risk

Container vulnerability scanning lowers the chances of attackers exploiting software flaws to gain unauthorized access, escalate privileges, or disrupt services. By continuously monitoring containers for new and existing vulnerabilities, organizations can prioritize patching critical risks and reduce their overall attack surface. Removing vulnerable packages and misconfigurations before deployment further prevents common attack vectors.

Regular scanning also helps maintain a clean baseline for container images, ensuring that old vulnerabilities aren’t inadvertently reintroduced over time. This level of vigilance is vital for organizations operating at scale or in regulated industries, where risk reduction directly correlates to business resilience and customer trust.

Improved Security Posture

Continuous container scanning establishes a foundation for strong security hygiene by automating many aspects of threat detection and response. As security insights are surfaced directly to development and operations teams, vulnerability management becomes ingrained into daily workflows rather than handled as an afterthought. This centralized, automated visibility also helps enforce organizational security benchmarks without manual review.

Maintaining an improved security posture through active scanning enables faster compliance with evolving standards, clearer audit trails, and better incident response. Organizations can demonstrate due diligence with up-to-date records of vulnerability assessments, which is increasingly demanded by partners, regulators, and customers as part of broader supply chain risk management.

Compliance

Many regulatory frameworks, including PCI DSS, HIPAA, and GDPR, mandate regular vulnerability assessments for software systems, including containers. Container vulnerability scanning directly supports compliance efforts by producing evidence of ongoing security checks, issue remediation, and policy enforcement. Automated scanning tools can generate reports that satisfy auditors and guide remediation priorities with clear, actionable findings.

Beyond regulatory requirements, compliance scanning allows security teams to map container configurations against best practices such as CIS Benchmarks or industry standards. This ensures all deployed assets meet internal and external obligations, reducing the risk of legal penalties, service interruptions, or reputational harm from unaddressed vulnerabilities.

Common Container Vulnerabilities Scanning Can Detect 

Outdated or Unpatched Libraries

Outdated or unpatched libraries are a primary target in container security scans because they often contain publicly known vulnerabilities that have been fixed in later releases. Attackers actively exploit these weaknesses, making it critical to monitor dependencies for updates and patches regularly. 

Container images frequently bundle several open-source packages that may fall behind on security updates, especially if images are built infrequently or from unofficial sources.

Misconfigurations in Container Settings

Configuration errors are a frequent source of vulnerabilities in containerized environments. Common misconfigurations include excessive privileges (such as running containers as root), insecure network settings, exposed ports, or enabled debugging interfaces. 

Attackers exploit these weaknesses to escalate privileges, laterally move within host systems, or exfiltrate sensitive data. Automated scanners help detect policy violations and unsafe settings before containers are deployed.

Embedded Secrets or Credentials

Storing secrets or credentials such as access tokens, API keys, or passwords directly within container images poses a significant security risk. If attackers extract these secrets from a compromised image, they can move laterally, escalate privileges, or access sensitive resources such as databases or cloud services. 

Scanning tools look for patterns that indicate hardcoded secrets, helping organizations discover and remediate exposures before containers are deployed. Secrets should be stored securely using dedicated secrets management solutions and never hardcoded in configuration files or environment variables within images. 

Insecure Base Images

Base images form the foundation for containerized applications and can inherit vulnerabilities present in their underlying operating system, default packages, or configuration. Insecure or outdated base images may lack critical security patches or contain unnecessary software, increasing the attack surface of every dependent image. 

Attackers often target widely-used and poorly-maintained public images to compromise large-scale deployments. Scanning tools can verify the provenance, age, and vulnerability status of base images, ensuring that only trusted sources are used. Organizations should standardize on minimal, verified base images and implement automated update workflows.

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Types of Container Security Scanning Technologies

Static Image Scanning

Static image scanning analyzes container images and artifacts while they are at rest—before deployment—to uncover vulnerabilities in operating system packages, application libraries, and other dependencies. These scans rely on signature-based analysis, comparing software components in the image to vulnerability databases to detect known issues. 

The process does not execute code, so it cannot detect runtime exploit behaviors, but it does offer a fast, reproducible check against published threats. This technology is highly effective for CI/CD pipelines, image registries, and pre-deployment gates, ensuring that only images that pass scan policies are allowed into production.

Runtime Security Monitoring

Runtime security monitoring tracks container activity during execution, searching for anomalous behavior, privilege escalation, or signs of attack. This class of scanning observes system calls, network activity, filesystem changes, and process life cycles in real time to flag unexpected patterns. 

Unlike static scanning, runtime monitoring can surface zero-day exploits, privilege misuse, or unauthorized data exfiltration as they occur. While runtime tools add operational overhead, their ability to detect threats inside running containers provides essential visibility for incident response and forensics. 

Compliance and Configuration Scanning

Compliance and configuration scanning assess container images and orchestrator configurations against established security policies and benchmarks. These tools evaluate Dockerfiles, Kubernetes manifests, and runtime policies to catch misconfigurations, insecure permissions, and policy violations. Such scans are essential for organizations subject to internal governance or regulatory requirements.

Configuration scans help ensure that containers adhere to best practices, such as least privilege, appropriate resource constraints, and secure networking setups. They also automate evidence collection for audits, generating reports to demonstrate compliance with standards such as CIS Docker and Kubernetes Benchmarks. 

Dependency and Supply Chain Scanning

Dependency and supply chain scanning examines all third-party libraries, frameworks, and other software packages present in container images. The goal is to identify risks not only in the code the team writes but also in external dependencies, which can represent the majority of a modern application’s attack surface. 

This approach uses tools that cross-reference component inventories with constantly updated vulnerability databases. Supply chain scanning can also detect typosquatting, backdoors, or tampered packages originating in public repositories. Integrating this scanning into CI/CD pipelines and image registries reduces the likelihood of deploying vulnerable software. 

Secret Detection and Hardcoded Credential Scanning

Secret detection tools search for hardcoded credentials—such as passwords, API tokens, private keys, or other sensitive information—within container images, source code, and configuration files. These static analysis engines use heuristics, pattern-matching, and known credential formats to catch common secrets leaking into images.

By surfacing embedded secrets before images reach registries or production, organizations can remediate leaks and rotate affected credentials promptly. Detecting secrets at every stage of the development pipeline helps enforce zero-trust practices, shifting secret management toward dedicated solutions, and preventing privilege escalation due to credential exposure.

5 Best Practices for Effective Container Vulnerability Scanning 

Here are some of the ways that organizations can ensure their containers are safe with a solid vulnerability scanning strategy.

1. Cover the Full Spectrum: Image, Registry, and Runtime Scanning

Scanning only container images at build time leaves blind spots. A complete approach should include registry scans for stored images and runtime scans for containers in operation. Registry scans catch vulnerabilities in dormant images before deployment, while runtime scanning helps detect drift and real-time threats.

By covering all stages (image creation, storage, and execution) organizations maintain visibility across the entire container lifecycle. This layered approach prevents gaps where an attacker could exploit unmonitored weaknesses.

2. Automate the Scanning Workflow

Manual vulnerability checks don’t scale in containerized environments. Automation ensures that scans run consistently across all images and deployments without relying on human intervention. CI/CD integrations, scheduled registry scans, and runtime monitoring agents are essential components of this automation.

Automation should also extend to reporting and alerting. Results need to flow into ticketing systems, dashboards, or chat tools so that security and development teams can act quickly without digging through scan logs manually.

3. Scan Beyond CVEs: Configurations, Secrets, Licenses

Not all risks come from CVEs. Misconfigurations, hardcoded secrets, and open-source license violations can be just as damaging. Scanning should therefore extend to Dockerfiles, Kubernetes manifests, and embedded secrets to provide a complete view of security posture.

Some tools can also identify license compliance issues, helping teams avoid legal or operational risks tied to incompatible or unapproved licenses. Expanding scanning scope ensures that vulnerabilities are not viewed only through the narrow lens of CVE data.

4. Prioritize by Risk and Automate Remediation

Raw scan results can overwhelm teams with thousands of issues. Prioritization is essential; using context such as exploitability, severity, and whether the component is exposed to external traffic. This helps focus remediation efforts on vulnerabilities that actually matter in production environments.

Where possible, remediation should be automated. For example, rebuilding images with updated packages, applying patches, or using pull requests to update dependencies can be integrated into workflows. Automation reduces manual overhead and ensures that vulnerabilities are resolved quickly and consistently.

5. Create Effective Remediation Workflows

Container vulnerability scanning means nothing with an effective remediation workflow. Container vulnerability scanners should enrich findings with context like package versions, exploit maturity, fix availability, and runtime relevance. Developers need precise guidance on which base images or libraries to upgrade, along with the potential impact and compatibility details. Integrating this information directly into workflows—through pull requests, issue trackers, or CI/CD feedback—ensures fixes are applied quickly and accurately.

To accelerate remediation, developers should have automated, reproducible steps for patching and testing. This includes verified upgrade paths, dependency resolution hints, and example configurations for secure replacements. Standardizing the remediation process and maintaining tight communication between DevSecOps and developers reduces friction and shortens the path from detection to secure deployment.

Runtime Container Vulnerability Scanning with Oligo

Oligo provides continuous container vulnerability scanning at runtime. It automatically scans container images to identify vulnerabilities as soon as they appear. Unlike traditional scanners that rely only on static analysis, Oligo continuously monitors the live application context, detecting which components are actually loaded and executed. This ensures that developers focus only on exploitable vulnerabilities, reducing noise and enabling faster, more targeted remediation.