
Top Container Security Best Practices for Safer Apps

Container security is a complex and multifaceted area that involves several different aspects of the software development lifecycle, infrastructure, and container runtime. Moreover, the security of containerized applications has raised concerns amongst the IT community, especially in cloud computing. It is often assumed that containers, a simple way of encapsulating applications, are by default not secure and could be prone to vulnerabilities.
What is Application Container Security?
Application container security refers to the security measures taken to protect the applications running inside containers, such as Docker containers or Kubernetes pods.
Application container security requires a holistic approach that covers the entire container lifecycle, from image creation to deployment, scaling, and decommissioning, and involves multiple layers of protection, such as image scanning, runtime security, network security, identity and access management, and orchestration platform security.
Definition and importance of application container security
Application container security is essential in today’s growing cyber threat landscape because containerization has become a popular approach to application deployment, and containers are attractive targets for attackers due to their ubiquity, scalability, and agility. Here are some reasons why application container security is crucial:
Protecting against container breakouts: Containers share the same operating system kernel as the host, which makes them vulnerable to exploits that can allow attackers to break out of the container and access the host or other containers.
Securing container images: Container images are the building blocks of containers, and they can contain vulnerabilities, malware, or other security issues.
Ensuring compliance: Containers and container orchestration platforms like Kubernetes are subject to various compliance regulations, such as HIPAA, PCI-DSS, or GDPR. Application container security measures can help enforce compliance requirements, such as access control, data encryption, or audit logging, and provide evidence of compliance to auditors.
Reducing attack surface: Application container security measures can help reduce the attack surface of containers and container orchestration platforms by enforcing security policies, restricting container communication, and minimizing the use of privileged containers or host mounts.
Integrating security into DevOps: Containers and container orchestration platforms are often used in DevOps workflows, where security needs to be integrated into the development, testing, and deployment processes. Application container security measures can provide automated security testing and feedback, integrate with CI/CD pipelines, and enable collaboration between security and development teams.
Examples of container security risks and vulnerabilities
Here are three examples of container security risks and vulnerabilities:
- Container breakout: A container breakout occurs when an attacker gains access to the host system by exploiting a vulnerability in the container runtime or the kernel. Containers share the same kernel as the host, which means that a vulnerability in one container can potentially affect other containers and the host.
- Vulnerable container images: Containers are built from images, which are snapshots of the application and its dependencies. These images can contain vulnerabilities or malware that can be exploited by attackers.
- Insecure network communication: Containers communicate with each other and with the outside world through network interfaces, which can be a potential source of security vulnerabilities.
Overview of container security solutions and best practices
Container security solutions provide a range of tools and technologies to help organizations secure their containerized applications and infrastructure. Here is an overview:
Container image scanning: Container image scanning tools analyze container images for known vulnerabilities and malware. They can provide a risk assessment report that identifies security issues and provides recommendations for remediation.
Runtime security: Runtime security solutions monitor container activity and behavior at runtime and can detect and prevent malicious activity. These solutions use techniques such as application whitelisting, network segmentation, and intrusion detection and prevention.
Secrets management: Secrets management solutions secure sensitive data such as passwords, API keys, and certificates used by containers and applications. They provide centralized storage and encryption for secrets and manage access and rotation policies.
Compliance management: Compliance management solutions ensure that containers and container orchestration platforms comply with industry and regulatory standards such as HIPAA, PCI-DSS, or GDPR. They provide automated audit logging, compliance reporting, and policy enforcement.
Threat intelligence: Threat intelligence solutions provide real-time threat detection and prevention for containers and container orchestration platforms. They use machine learning, behavioral analysis, and threat feeds to identify and respond to security incidents.
Securing Container Infrastructure
One important aspect of securing container infrastructure is ensuring that the containers themselves are secure. This can be done by scanning container images for known vulnerabilities before they are deployed and by implementing access controls to limit who can interact with the containers. It’s also important to regularly update container images to patch any newly discovered vulnerabilities.
Another important aspect of container security is ensuring that the host operating system and other components of the container infrastructure are secure. This involves implementing security best practices such as strong authentication and authorization mechanisms, network segmentation, and regular vulnerability scanning and patching.
Securing container infrastructure also requires monitoring and logging to detect and respond to any potential security incidents. This involves implementing tools to monitor container activity, logging all relevant events, and using machine learning or other advanced techniques to detect and respond to potential threats.
Best practices for securing the container environment and infrastructure
Here are some best practices that can help organizations ensure that their container environments and infrastructure are secure and protected against potential security threats.
- Use trusted container images: Only use container images from trusted sources, and verify the authenticity of the images before deploying them. It’s important to scan container images for vulnerabilities and malware, and to ensure that images are signed by the developer to prevent tampering.
- Implement access controls: Use role-based access control (RBAC) to limit who can interact with containers, and ensure that containers only have the permissions they need to function. Use tools like Kubernetes to manage access control for containers.
- Keep containers up-to-date: Regularly update container images to ensure that they are patched against known vulnerabilities. Use automated tools to update images and to ensure that the latest security patches are applied.
- Harden the container host: Ensure that the host operating system is secure and up-to-date, and that all unnecessary services and ports are disabled. Use security tools like firewalls and intrusion detection/prevention systems to protect the host.
- Isolate containers: Use network segmentation to isolate containers from one another and from the host operating system. Use tools like Kubernetes to manage network isolation and to prevent containers from communicating with unauthorized networks or endpoints.
- Educate users: Ensure that users are trained on container security best practices, and provide them with the tools and resources they need to operate containers securely.
- Use multi-factor authentication: Require multi-factor authentication for access to container management tools and resources. Use tools like Okta or Duo to manage multi-factor authentication for container environments.
- Regularly review security policies: Regularly review and update security policies and procedures to ensure that they remain effective and up-to-date with changing security threats and best practices.
Importance of securing container infrastructure
Securing the container environment and infrastructure is an important aspect of container security because containers are not isolated from their host system or the wider network. Container security in the software supply chain or CI/CD pipeline involves the following best practices:
- Secure code development practices: Developers should follow secure coding practices, such as input validation and sanitization, to prevent common vulnerabilities such as injection attacks.
- Secure container image creation: Developers should create secure container images by only using trusted sources and ensuring that images are kept up to date with security patches.
- Image scanning: Images should be scanned for vulnerabilities and malware before they are deployed to the production environment.
Explanation of container runtime security
Container runtime security can help to protect containerized applications and their underlying infrastructure against a wide range of security threats. Container runtime security works by using a combination of security tools and techniques, such as:
Network segmentation: Containers are isolated from one another and from the host operating system using network segmentation. This helps to prevent unauthorized access and communication between containers.
Logging and monitoring: Logging and monitoring tools are used to track container activity and detect potential security incidents. These tools can be used to detect suspicious behavior, such as attempts to access unauthorized resources or make unauthorized modifications to the container.
Intrusion detection/prevention: Intrusion detection/prevention systems (IDS/IPS) can be used to detect and prevent unauthorized access and malicious activity. These systems can be configured to block traffic from unauthorized sources or to alert administrators to potential security threats.
Secure communication: Secure communication protocols, such as Transport Layer Security (TLS), can be used to protect communication between containers and between containers and external systems. Tools like Istio or Linkerd can be used to manage communication security.
Vulnerability management: Regularly updating container images and underlying infrastructure with the latest security patches and updates can help to prevent known vulnerabilities from being exploited.

Providing Security to Docker Containers
Docker is a widely used containerization technology that enables developers to package applications and their dependencies into portable, isolated containers that can be deployed in any environment. Docker container security is essential to ensure the safety and protection of the application and its underlying infrastructure.
Different types of security tools and their functions
Using a combination of Docker security tools can help organizations enhance the security of their Docker containers and mitigate the risks associated with running containerized applications. Here are some of the most common types of Docker security tools and their functions:
- Vulnerability Scanners
Vulnerability scanners are tools that scan Docker images and containers for known vulnerabilities and provide recommendations for remediation. These tools can help organizations identify and mitigate security risks in their Docker environment.
- Image Scanners
Image scanners are tools that analyze Docker images for potential security issues such as malware, unapproved components, and misconfigurations. These tools can help organizations ensure that only approved and secure Docker images are used in their environment.
- Runtime Security Tools
Runtime security tools are designed to monitor and protect Docker containers while they are running. These tools can detect and prevent security threats such as unauthorized access, privilege escalation, and denial-of-service attacks.
- Container Network Security Tools
Container network security tools are designed to secure the network connections between Docker containers and the wider network. These tools can help organizations ensure that containers are isolated from the rest of the network and that network traffic is encrypted and authenticated.
- Logging and Monitoring Tools
Logging and monitoring tools are designed to provide real-time visibility into the Docker environment, including container activity, network traffic, and system events. These tools can help organizations detect and respond to security incidents in a timely manner.
- Identity and Access Management (IAM) Tools
IAM tools are designed to manage user access to Docker containers and resources. These tools can help organizations enforce access control policies, authenticate users, and manage permissions.
5 Best Practices for Container Security
Best practices for container security are a set of guidelines and recommendations that can help organizations mitigate the risks associated with running containerized applications. Here are some of the most common best practices for container security:
#1 Apply the Principle of Least Privilege
The Principle of Least Privilege means granting containers and processes only the minimum necessary permissions and access rights to resources, such as network, storage, and system resources. This approach can prevent containers from performing actions outside of their intended purpose, which can reduce the risk of privilege escalation attacks.
For example, a container running a web application should only have access to the network ports required for the application to function, such as HTTP and HTTPS. It should not have access to other network ports or system resources that are not required for the application’s operation.
#2: Keep Containers Up to Date
This practice involves regularly updating container images and dependencies to address security vulnerabilities and ensure that the containerized application is running on the latest and most secure software versions.
#3 Use Secure Hosts and Registries
Using secure hosts and registries is a crucial best practice for container security that can help prevent unauthorized access, protect against image tampering, enforce security policies, and improve auditability and traceability.
#4: Monitor and Analyze Container Activity
Monitoring and analyzing container activity can help detect and prevent security breaches, identify security risks, ensure compliance with security policies, and provide insights for continuous improvement.
#5: Implement Network Segmentation
Isolating containers and container infrastructure from the rest of the network using network segmentation can help prevent attackers from accessing containerized applications and data, and limit the damage caused by security breaches.
Conclusion:
In summary, application container security refers to the measures taken to secure the applications running inside containers such as Docker containers or Kubernetes pods. It requires a holistic approach covering the entire container lifecycle and involves multiple layers of protection such as image scanning, runtime security, network security, identity and access management, and orchestration platform security.
Best practices for securing container infrastructure include using trusted container images, implementing access controls, keeping containers up-to-date, and monitoring and logging to detect and respond to any potential security incidents. Container security is essential in today’s growing cyber threat landscape as containers are attractive targets for attackers due to their ubiquity, scalability, and agility.
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*** This is a Security Bloggers Network syndicated blog from GuardRails authored by GuardRails. Read the original post at: https://blog.guardrails.io/top-container-security-best-practices-for-safer-apps/