CI/CD Security: Advanced Best Practices to Secure Your Pipelines

CI/CD security works by implementing security measures at every stage of the software development pipeline:

• Development: In the development environment, access controls and encryption are used to prevent unauthorized access and code tampering. The code repository is similarly protected, with measures such as two-factor authentication and automatic vulnerability scanning to ensure that the codebase remains secure.
• Build: The build system is another critical element in CI/CD security. Here, tools like static code analysis and software composition analysis are used to identify and fix potential security issues before the software is deployed. These tools check for common security vulnerabilities, such as SQL injection or cross-site scripting, and alert the development team so they can address the issues.
• Deployment: At this final stage, CI/CD security involves measures like automated deployment, which minimizes the risk of human error; dynamic testing, which simulates attacks against running applications in test environments; and continuous monitoring, which allows for rapid response to security incidents.

One of the main risks to the software delivery pipeline is supply chain attacks. Some of the early attacks include NotPetya and ASUS Live Update. Some more recent attacks further illustrate how neglecting CI/CD security can be catastrophic.

The Microsoft Exchange Server attack, which occurred in early 2021, is a stark reminder of the importance of robust CI/CD security. In this attack, a group of hackers exploited vulnerabilities in the Microsoft Exchange Server to gain access to thousands of servers worldwide. This was possible because the software was not sufficiently hardened before deployment, allowing attackers to exploit these vulnerabilities.

The lesson learned from this attack is the importance of thorough security testing and vulnerability scanning before deployment in the CI/CD pipeline. By identifying and fixing security vulnerabilities before software is deployed, companies can significantly reduce the risk of similar attacks.

The SolarWinds attack, which took place in late 2020, was probably the largest and most severe global-scale supply chain attack. Attackers were able to infiltrate SolarWinds’ development environment and insert malicious code into the company’s software update system. This enabled them to distribute their malware to thousands of SolarWinds’ customers, which included US government agencies and a majority of Fortune 500 companies.

Now that we’ve reviewed basic security measures and how they can prevent supply chain and other attacks, let’s cover some more advanced CI/CD security best practices that can help you gain the edge over sophisticated attackers.

Binary authorization ensures that only trusted and verified code gets deployed in your production environment.

Implementing binary authorization involves creating and enforcing policies that dictate which binaries can be deployed in your environment. These policies should be based on various parameters, such as the origin of the binary, its compliance with certain security checks, and its approval status.

Threat modeling is the process of identifying, understanding, and mitigating potential security threats in a system. Here are a few steps you can take to perform threat modeling for your CI/CD environment:

1. Understand the architecture of your CI/CD pipeline: This includes mapping out all the components and their interactions, identifying the assets, and understanding the data flows.
2. Identify potential threats to your pipeline: This could include unauthorized access, data leakage, code tampering, or any other security threats. Once you have identified these threats, you should assess their potential impact and likelihood of occurrence.
3. Design strategies to mitigate the threats: This could involve implementing additional security controls, modifying the architecture of your pipeline, or adopting new security practices.

The security of your runtime environment is equally important as the security of your CI/CD pipeline. A compromised runtime environment can lead to serious security breaches, including data leakage, unauthorized access, and service disruption.

Securing your runtime environment involves several practices:

• Regularly update the runtime environment: This includes updating the operating system, the runtime and orchestration platforms (like Docker or Kubernetes), and any other components used in your environment.
• Restrict privileges in your runtime environment: Limit the actions that can be performed in your environment and only grant necessary permissions. By doing so, even if an attacker manages to gain access to your environment, they will be limited in what they can do.
• Isolate runtime environments: Run each application or service in its own isolated environment, which will prevent any potential security threats from spreading across your system.

Dependencies are a common vector threat vector in CI/CD pipelines. A single vulnerable dependency can compromise an entire system. Therefore, it’s crucial to continuously scan your dependencies for vulnerabilities.

Continuous dependency scanning involves integrating tools into your CI/CD pipeline that can scan the codebase, container images, and any other components used in the pipeline. Additionally, you should also monitor dependencies for changes. This could include new versions, updates, or patches, alerting you to potential security threats.

Secrets, such as API keys, passwords, and tokens, are often used in CI/CD pipelines. However, if these secrets are leaked or stolen, they can be used to gain unauthorized access to your system. Therefore, it’s crucial to manage and protect your secrets properly.

Secrets management involves securely storing, accessing, and using your secrets. This typically involves using a secure vault to store your secrets, encrypting your secrets both at rest and in transit, and using secure methods to access your secrets. Moreover, regularly changing your secrets is crucial to prevent unauthorized access. By doing so, even if an attacker manages to steal your secret, they won’t be able to use it for long.

Securing the CI/CD pipeline is an essential aspect of modern software development. The software delivery pipeline is rife with potential vulnerabilities, from the codebase to the deployment stage. With the rise in devastating software supply chain attacks, CI/CD security serves as a critical line of defense.

To properly defend your CI/CD environment, multiple layers of security measures should be applied at each stage of the development pipeline. Access control mechanisms, automated vulnerability scans, and encryption are critical to securing the codebase and development environment. In the build and deployment phases, employing tools for static and dynamic code analysis, as well as implementing immutable infrastructure, can significantly mitigate the risk of security breaches.

Advanced practices such as CI/CD threat modeling, continuous dependency scanning, secret management, and dynamic environment hardening offer additional resilience against sophisticated attacks.

The risks are high, but effective tools and methodologies are available to mitigate them. With diligent implementation and ongoing vigilance, organizations can secure their CI/CD pipelines and their business integrity against evolving threats.

Editor’s Note: The opinions expressed in this guest author article are solely those of the contributor and do not necessarily reflect those of Tripwire.