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Amazon Inspector: Basic Concepts

1. Amazon Inspector Overview

1.1 What Is It and What Is It For?

  • Amazon Inspector automates security analyses on compute resources (EC2, ECR, Lambda) to identify vulnerabilities and insecure configurations.
  • It creates findings that detail the type of vulnerability (for example, known CVEs, outdated packages, configuration issues) and the severity (Critical, High, Medium, etc.).
  • It centralizes reports for prioritization, remediation, and tracking, allowing teams to respond quickly to threats.

1.2 Difference Between Amazon Inspector and Other Tools

  • Amazon Inspector vs GuardDuty

- GuardDuty focuses on detecting anomalous behaviors and intrusions (log and traffic analysis).

- Inspector is focused on vulnerability scanning and configuration assessments on EC2, ECR, Lambda.

  • Amazon Inspector vs AWS Config

- AWS Config tracks changes in resource configurations and verifies compliance with rules.

- Inspector performs specific security tests (including CVE databases) to detect vulnerable software and dependencies.

1.3 Use Cases

  • Automatic scanning of new EC2 instances: Whenever new instances are launched, Inspector automatically evaluates and alerts if there are issues.
  • Container image scanning in ECR: Ensures images are free of critical CVEs before being deployed to production.
  • Continuous verification of Lambda functions: Checks libraries and dependencies of your functions without the need for manual intervention.

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2. Basic Configuration

2.1 Enabling Amazon Inspector

  1. Access the AWS Management Console and search for "Amazon Inspector".
  2. Click Enable Amazon Inspector.
  3. If desired, check the options for Inspector to perform automatic scans on resources (EC2, ECR, Lambda).
  4. Define whether you want to use advanced integrity (SNS topics, Security Hub integrations, etc.).

2.2 Verification Scope

  • EC2 Instances:

- Does Inspector use an agent? In the latest version, it is no longer necessary to install a manual agent: it integrates via AWS Systems Manager (SSM) to collect software data.

  • ECR Images:

- Inspector scans when an image is uploaded or at periodic intervals.

- It identifies CVEs in OS or application libraries (e.g., flaws in OpenSSL, glibc, etc.).

  • Lambda Functions:

- Checks packages and dependencies contained in the function code, flagging known vulnerabilities.

- Compares signatures and versions against CVE databases.

2.3 Scan Frequency

  • Continuous Scanning: Amazon Inspector continuously monitors, triggering checks whenever there are changes or at pre-configured intervals.
  • Manual Scanning (On-Demand): It is also possible to initiate on-demand scans for certain resources via console or API, if you want an immediate test.

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3. Managing Findings

3.1 Severities and Priorities

Findings are classified as Critical, High, Medium, Low, based on:

  • CVSS (Common Vulnerability Scoring System) or AWS internal metrics.
  • Impact on application functionality.
  • Exploitability (are there public exploits for that flaw?).

3.2 Visualization and Actions

  • Amazon Inspector Console:

- Displays the list of findings, severity, and remediation recommendations.

- Filter by resource (instances, containers, functions) or by detection date.

  • AWS Security Hub:

- If enabled, consolidates Inspector findings with those from other services (GuardDuty, Macie, etc.).

- You can create rules in Security Hub to notify via Amazon EventBridge and trigger automatic remediations.

3.3 Integrations with Notifications and Automation

  • Amazon EventBridge (CloudWatch Events):

- Whenever Inspector generates a high-severity finding, for example, you can trigger an auto-remediation workflow (Lambda functions) or Slack/Teams notifications.

  • SNS (Simple Notification Service):

- Send emails or SMS to the security team for each new critical finding.

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4. Advanced Features

4.1 Granular Resource Selection

  • Resource Exclusion:

- If there are EC2 instances that don't need to be scanned (for example, disposable test environments), you can explicitly exclude them.

  • Tags for Segmenting Scans:

- Use tags like "Environment=Production" or "Department=Finance" to filter resources and apply specific scanning policies.

4.2 Customizing Scan Policies

  • Scan Policies:

- By default, Inspector uses AWS-recommended verification policies.

- It is possible to customize the scope of checks (for example, if you want to ignore CVEs for package X or if a known mitigator already exists).

  • ISV and Plugin Addition:

- Amazon Inspector doesn't have "plugins" in the Suricata or Nessus sense, but you can use integrations with partners (Splunk, Rapid7, Snyk) to complement detection and correlate findings.

4.3 Using Compliance Rules

  • While Inspector is focused on vulnerabilities, there are checks that also map to compliance standards (for example, PCI-DSS) if the identified flaw is directly related to framework requirements.

4.4 Automated Response

  • Remediation Lambda:

- When facing specific findings (e.g., vulnerable Apache version), a Lambda function can run patch scripts or AMI replacement.

- It is important to control carefully to avoid "auto-patch" breaking production applications.

  • Terminating Critical Instances:

- If severe flaws are detected in EC2 that could compromise the network, some organizations prefer to isolate or terminate the instance to prevent escalation.

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5. Best Practices

  1. Enable in All Regions and Accounts

- Vulnerabilities can go unnoticed in rarely used regions or in test/staging accounts. Enable Inspector at the organizational level (AWS Organizations) whenever possible.

  1. CI/CD Integration

- If you build Docker images that go to ECR, run scanners (Trivy, Anchor, etc.) in the pipeline and use Inspector as an additional security layer.

- This way, flaws are blocked before reaching the registry itself.

  1. Prioritize High-Severity Fixes

- Create alerts and workflows that emphasize critical vulnerabilities or those with known exploits.

  1. Periodic Review of Old Findings

- The nature of vulnerabilities can change over time. What was "medium" can become "high" if exploits emerge. Maintain a revalidation routine.

  1. Apply Solid Patch Management

- Inspector identifies flaws but does not fix them on its own. It is essential to have a well-defined patching process (via AWS Systems Manager or other tools).

  1. Document Exceptions

- If a finding is not applicable, record why it was ignored (for example, "this package is disabled" or "use of a sidecar container that mitigates the flaw").

- This avoids confusion in future audits.

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6. Cost Model

  • The cost of Amazon Inspector depends on the number of resources scanned and the frequency of scans.
  • EC2 and Lambda: Billing is per analysis per resource.
  • ECR: Billed per image scan; repeated scans also count if the image is modified.
  • Always check the official pricing page for updated details.

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7. Conclusion

Amazon Inspector is a fundamental tool for maintaining a continuous security cycle on AWS. It identifies vulnerabilities in EC2, containers (ECR), and Lambda functions, allowing DevOps and security teams to resolve gaps quickly. As you advance in usage, you can adopt custom policies, automate responses, and integrate with SIEM services or AWS Security Hub to create a unified security posture.

For companies that already have mature DevSecOps processes, Inspector brings practicality and scalability, consolidating the scanning of various resource types in one place. Even for smaller teams, the native integration and simple interface allow the service to be enabled quickly and generate immediate value, pointing out critical issues that could become entry points for attacks.

Whether in a small environment or multi-account infrastructure, Amazon Inspector can elevate the quality of security and assist with compliance, minimizing the risk of incidents that could compromise data or disrupt operations.

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Additional Links

awsinspectorsecurityvulnerabilitiesec2ecrlambda