With companies moving to cloud infrastructure, the overall deployment process has drastically changed. This has led to increased usage of containers and Kubernetes. Containers act as building blocks for microservice architecture applications where companies have multiple services running for different use cases rather than a single monolithic application. Although the shift offers a lot of benefits for the development teams, it comes with various security challenges. This is where container security scanning comes into the picture.
Container security scanning tools help to find and prevent security vulnerabilities in the container ecosystem. Companies often use these tools in the CI/CD pipeline during the build processes.
In this blog post, we will discuss what container scanners are, along with common vulnerabilities found in containers and how to avoid them. We will also discuss the key objectives and benefits of using container security scanning tools.
What is Container Security Scanning?
Container security scanning is a process where different scanning tools are used to look into container images for any security vulnerabilities. These containers can be in the static stage or in the running stage. The end goal of container security scanning is to find vulnerabilities, misconfigurations in the cloud infra, and complication violations.
Securing containers used by companies in production is critical as they can act as entry points for threat actors. Container security scanning tools act as an important tool for enterprises to help secure the overall supply chain environment.
Types of Container Security Scans
As discussed in the previous section, container security scanning tools can scan containers in runtime or static mode. This is known as Dynamic and Static Analysis, respectively. Let’s understand more about them.
- Static Analysis: This means effectively performing vulnerability tests on images at the container layer to search for vulnerabilities in the base image, code, and the application’s dependencies. Static analysis is usually done during the build phase of the software, and it is effective in identifying problems at an early stage.
- Dynamic Analysis: Dynamic analysis is another aspect that unravels the behavior and interactions of the container during its execution phase in addition to the container’s components. It allows real-time monitoring of running containers for threats and activity anomalies.
Key Objectives of Container Security Scanning
It is important to perform frequent container security scans when using containerized applications. The process helps to achieve multiple objectives to improve the overall security posture. In this section, we will discuss these objectives in depth.
1. Identifying Vulnerabilities in Container Images
One of the main objectives of container security scanning is to identify security vulnerabilities in the containers. These vulnerabilities can either be in the base image used in the container or the third-party packages installed on it. Companies often use this data to help developers secure the container to avoid exploitation by attackers. If the vulnerability counts for containers are too high or exceed the company’s risk appetite, they can also block deployments.
2. Detecting Misconfigurations and Security Risks
Container security scanning not only helps identify vulnerabilities but can also help find misconfiguration issues related to containers. Common examples include wrong permissions, use of root access, or exposed information. Organizations need to make sure that containers are securely configured to avoid any unauthorized access or make the container an entry point for attackers.
3. Ensuring Compliance with Security Standards
Compliance refers to following certain guidelines or specific terms. Companies have to adhere to compliance for various reasons, such as customer trust, security, etc. Compliance depends on the industry in which the company is working, such as the HIPAA used by healthcare companies. Compliance standards, such as SOC II, HIPAA, etc, have strict guidelines to ensure the security of containers. Companies have to pay hefty fines to regulatory bodies if they violate such regulations. Container security scanning tools ensure that the containers are secure from risks and are working as per compliance requirements.
4. Preventing Deployment of Insecure Containers
As discussed earlier, companies can prevent the deployment of insecure containers as part of CI/CD checks. The blocking is usually to prevent vulnerable containers from getting live (in production) where anyone using the application can try to hack into them using known vulnerabilities. The goal is to prevent attackers from compromising the system and leaking sensitive information.
Key Components of Container Security Scanning
Container security scanning is a long process with multiple components performing different jobs. Let’s understand these key components.
Image Scanning
Containers and Images are related terms but are interchangeably used by developers. Think of the image as a complete package that has everything required for the application. This included the code of the application, run time environment, etc. Containers, on the other hand, are running instances of the same image. The containers are isolated environments but can interact with one another.
Image scanning is a process of scanning the same package we talked about. As part of the process, container security scanning solutions try to find vulnerabilities in the base image, the application code, and the dependencies used by the application.
Configuration Assessment
Configuration validation or assessment is used to verify that there are no insecure configurations (aka misconfigurations) in the container and its surroundings. Some of the common misconfigurations include using default passwords, insecure passwords, and hardcoded API keys or tokens.
Vulnerability Detection
Vulnerability detection is another component of container security scanning solutions. This component is used to detect vulnerabilities in the software component of the container. Vulnerability databases such as OSV, Github Advisory, and NIST Vulnerability Database are used to fetch the list of known vulnerabilities in the software.
Compliance Checking
The compliance checking component is used to validate if the container being used is following the guidelines by scanning them frequently. Scanning for compliance includes making sure that the containers are adhering to CIS benchmarks and other guidelines such as NIST.
Runtime monitoring
The goal of runtime monitoring is to identify threats in real-time when the container is in a running state. This also includes checking for any abnormal behavior by the container, such as sending out massive outbound calls to a malicious domain.
Runtime security comes in very handy in identifying day-to-day security issues and acts as a layer of protection.
How Does a Container Security Scanner Work?
Most container security scanning solutions work by checking the information in the container itself and checking for vulnerabilities in the runtime using a multi-step approach. This process combines the best elements of static analysis, dynamic analysis, and runtime monitoring to ensure that at any single moment, you will have a full picture of the container’s security.
This scanning process usually starts with a static analysis of the container. The container scanner takes a look at the layers of the image, which include the base operating system, installed packages, and application code. It then cross-references the components against known vulnerability databases and security advisories to determine any risks.
Dynamic analysis and runtime monitoring only run when the container is up & running. Dynamic analysis can be performed by detecting unusual behaviors or communication with any untrusted or malicious domain, network, etc, that may raise the security alarm. It subscribes to heartbeat and perf-events data streams provided by the container runtime, continuously monitoring the behavior of a given container in terms of its operations (created/started/stopped/deleted/etc), network connections, and resource usage patterns.
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Read GuideDifferent Vulnerabilities and Risks in Containers
When it comes to security vulnerabilities in containers, they are no different from Web & APIs. Containers also have various types of security vulnerabilities, and each of them poses a different risk. Let’s discuss some of the vulnerabilities.
1. Operating System Vulnerabilities
Containers are isolated environments, but they share the host OS kernel, which implies that they are vulnerable to kernel-level attacks. These vulnerabilities can be easily identified by thoroughly scanning the image. A major risk that the containerized environment poses is that the host OS that the containers are built on is exposed to the internet (based on the configuration), thereby being prone to continual attacks.
However, by frequently patching and updating the host OS, it is possible to reduce this risk and decrease the overall attack surface area.
2. Application Dependencies and Library Issues
Applications can contain a miscellaneous number of other sub-application libraries as well as dependencies that can have known vulnerabilities. Scanning containers helps recognize and update such parts. In some cases, dependencies may keep getting vulnerabilities from researchers (such as Tensorflow) that would allow unauthorized access into an application and hence require frequent updates and scanning.
3. Misconfigurations and Insecure Defaults
A lot of vulnerabilities in containers arise when developers don’t replace default or placeholder secrets or settings with secure ones. One common example is when an application keeps using the default password for a known CMS like WordPress that was hard-coded in the base image. The default credentials vulnerability class is one of the favorites for attackers as they don’t have to spend time understanding and breaking the application logic.
4. Supply Chain Risks and Compromised Base Images
Supply chain attacks have recently spiked a lot (such as the recent XZ attack). Most companies relying on containers use images directly from the public registry. If the base image is removed from the registry and replaced with a malicious one, systems can easily get compromised. One other way is when developers make spelling mistakes when importing images, such as using Python instead of Python. Attackers usually push images with spelling mistakes to public registries, waiting for developers to make mistakes.
What is the Process of Container Security Scanning?
The process of container security scanning involves several key steps that eventually help in maintaining the security of containerized applications.
Let’s break down this process of container security scanning:
1. Static Analysis Techniques
The first type scans container images in their offline mode to check for vulnerabilities in the base image, application code, and dependencies. This often occurs using vulnerability databases and security advisories. Static code analysis assists in identifying problems at an early stage and in making sure the container image being deployed does not contain any known security vulnerabilities.
2. Dynamic Analysis Methods
The other type of analysis is dynamic analysis, where the automation tool or security engineer analyzes running containers to identify threats that exist in the running container. This helps ensure that security incidents are detected and dealt with as they happen. TL;DR is Dynamic analysis, which acts as the second line of defense by monitoring the container’s behavior and interactions during execution.
3. Integrating Scanning into CI/CD Pipelines
Deployment, which is done through the CI/CD pipelines, incorporates security scanning to perform thorough scanning of containers for any vulnerability or misconfiguration. The integration of container security scanning solutions into the CI/CD pipeline allows organizations to possess a secure, developed, and deployed environment.
4. Interpreting Scan Results and Remediation
Once the process of container security scanning is done, the next step is to interpret the results and take action to address the vulnerabilities and risks. Let’s look at the factors that can help analyze the scan results.
5. Understanding Container Security Scan Reports
Container security scan reports provide detailed information about the discovered weaknesses, misconfigurations, and compliance problems. These reports are important for remediation, and this is why one has to understand them. This implies that after going through the scan reports, organizations can know the areas of concern and work on them.
6. Prioritizing Vulnerabilities
Not all vulnerabilities are of equal measure and should not be handled in the same manner. When multiple vulnerabilities are found, risk factors should be taken into account, emphasizing those vulnerabilities that might cause the most harm to the enterprise. By addressing the critical vulnerabilities first, organizations can eliminate the most dangerous risks and, in the process, protect their containerized applications.
7. Patching and Updating Vulnerable Components
The management of vulnerabilities requires patching and updating all the compromised components where the vulnerabilities have been identified. This includes updating the base image, the application libraries, and the dependencies. Frequent patching and updating of the components helps to create a secure infrastructure.
8. Hardening Container Configurations
The container hardening process is used to fix misconfigurations discovered in the containers. It is also used to ensure that proper security standards are applied to it. Some security standards include using secure passwords, avoiding unnecessary access, and securing sensitive information. Hardening of containers is also important for companies in terms of compliance.
Container Security Scanning Benefits
Container security scanning offers various benefits to companies that are trying to improve their security posture. Let’s discuss some of the key benefits:
- Enhanced Security: Container security scanning helps identify and deal with vulnerabilities and misconfigurations to improve the security of containerized applications. This means that organizations get proactive rather than reactive in addressing security problems, hence decreasing the likelihood of a breach occurring.
- Compliance: Compliance checks offered by container security scanning solutions assist in keeping abreast with the set industry standard and ensuring that compliance with regulatory bodies is maintained.
- Preventing Breaches: The scanning process helps to prevent data breaches as there is no way that a developer will be allowed to deploy insecure containers if companies have proper container security scanning in place.
- Continuous Monitoring: By constantly tracking running containers, it is easier to address threats that are in the process of execution or are in progress. The runtime monitoring is another level of protection since it constantly evaluates the container and its operations.
- Improved Resource Allocation: Container security scanning helps companies improve the overall resource allocation and reduce costs associated with security management.
Best Practices in Container Security Scanning
To make sure that the containers are secure to use, developers need to follow a set of best practices. Here are some of the key best practices for effective container security scanning:
#1. Scaling Security Scanning in Large Deployments
With big companies using containers for deployment, it is important to automate the container security scanning process using different solutions. For large-scale applications, companies can’t rely on developers to find issues in the containers, keep an eye on new CVEs, and keep looking for sensitive information being disclosed or leaked via containers. Companies should build automation pipelines to secure the complete lifecycle of containers, from onboarding them to the registry to taking them to the internet (shipping to production).
#2. Balancing Security with Development Speed
With agile methodologies, companies like to ship fast nowadays, but it’s important to ensure that proper security controls are in place when it comes to deploying applications. When developers try to ship applications fast, they tend to make mistakes such as hard-coding API keys, turning off debug mode, adding security controls, etc. Companies can ensure that their containers are secure by using container security scanning solutions in the CI/CD pipelines and training the development and DevOps teams about security controls.
#3. Continuous Monitoring and Automated Remediation
Continuous scanning and subsequent controls help with tracking new threats as they occur (in real-time), with the process of eliminating them automatically. This includes addressing the issue of runtime monitoring as well as coming up with an automated patching and updating process. In this way, organizations can enforce constant monitoring and automated remediation of security incidents and maintain a secure state while reacting swiftly to security incidents.
#4. Implementing a Secure Container Registry
For companies that heavily rely on containers, it is essential to invest in a secure container registry or satisfactory that will assist in reducing the use of dangerous and unapproved container images. This can be achieved by signing images, using access control measures, and periodically scanning the registry for any known vulnerabilities. Using a container artifact also ensures that developers are not using malicious images or being prey to typosquatting attacks.
Conclusion
Container security scanning is a crucial activity when it comes to scanning containerized applications and improving their risk posture. By pointing out risks, misconfigurations, and compliance issues, security scanning can help strengthen the security of containers, as well as minimize the probability of an attack.
For better coverage and security, it is important to ensure that container security scanning solutions are incorporated into the CI/CD pipeline to prevent any insecure container from going live, making a target on the company’s back.
FAQs
Container security scanning is the process of scanning container images and running containers to detect vulnerabilities, configuration problems, and compliance violations. The goal of container security scanning is to ensure the containers are secure from any vulnerabilities, hence avoiding serious damage to the company in terms of money and reputation.
Container scanning can identify vulnerabilities in the base image and dependencies used by the application, misconfiguration, and compliance violations. It can also assist in the identification of security threats and the determination of the security state of containers before they are shipped out (or deployed).
Container scanning in DevSecOps can be defined as the incorporation of the scanning of containers in the application development pipeline aimed at the early identification of security issues before the containers are deployed to production.
Container vulnerability scanning can be defined as a systematic and multistep process of identifying the vulnerabilities in the containers to prevent attacks by threat actors and unauthorized access to sensitive information (PII).
The tools that can be used in container security are Docker Security Scanning and Clair. These tools can perform thorough container security by discovering risks, identifying misconfigurations, and addressing compliance problems with containerized applications.
