CI/CD Pipeline Security Best Practices

Continuous Integration/Continuous Development (CI/CD) pipelines lie at the core of the DevSecOps philosophy. CI/CD streamlines software delivery by providing automation tools that consistently and frequently integrate, test, and deploy the code to production.

While essential for efficient delivery, insecure CI/CD pipelines pose an real security risk. They can lead to serious consequences, like operational disruptions, delays in new feature delivery, and serious security breaches, resulting in lost revenue, damaged reputations, and even legal issues.

As teams adopt the CI/CD approach to streamline code delivery, the right DevSecOps tools and security practices must be implemented to secure the pipelines.

Let's discusses CI/CD pipeline security alongside risks, practices, and tools for safeguarding the various stages of the pipelines.

What Is a CI/CD Pipeline?

The CI/CD pipeline is a sequence of automated processes that run sequentially to ensure a new code version is ready for deployment to end users. Think of it as a quality control system that ensures only functional and high-quality code reaches your users. 

Every time a developer makes a change, the pipeline moves it through a series of checkpoints: building the code, running tests, fixing bugs, and so on. If everything passes, the code is released to end users. This process enables DevOps teams to deliver reliable software at lightning-fast speed while maintaining a consistent process for software releases. 

The CI/CD pipeline typically consists of tools for code storage and management, compilation, unit testing, code analysis, security checks, and binary creation. For containerized environments, the pipeline also involves packaging the code into a container image for deployment across a hybrid cloud.

While the pipeline streamlines software updates, it can simultaneously serve as an attack vector for cybercriminals. For instance, most modern CI/CD tools pull code from cloud-based code repositories and integrate third-party libraries. Without adequate CI/CD security, threat actors can exploit loopholes in your system to carry out malicious activities.

Any team using the CI/CD approach must implement stringent security measures at every pipeline stage to prevent vulnerabilities while maintaining speed and efficiency.

CI/CD Pipeline Stages

The CI process involves merging and testing code changes, while CD deals with rolling out changes to end users. The CI/CD pipeline has four main stages: source, build, test, and deploy. 

Software teams looking to de-risk their pipelines must understand the common risks associated with each stage and learn how to address them. Let’s explore that now. 

Source Stage

Every software application is comprised of lines of code. In the source stage of the CI/CD process, two things happen: First, we write the source code and store and manage the software in a controlled and versioned manner.

Code creation takes place on the developer’s local machine. A version control system like Git or Subversion is installed in the project to track file changes and allow authorized users to retrieve or revert to previous versions. Git is commonly paired with Git-based repository hosting services like GitHub or GitLab to facilitate collaboration.

The CI/CD pipeline begins at the source stage and is usually triggered by a new commit or pull request. The new code undergoes initial quality checks, like linting or syntax checks, to ensure it follows predefined standards and styles.

Common security risks in the source stage of the CI/CD pipeline include:

1. Hard-coded secrets or credentials in the codebase: Once code is pushed to a public repository, anyone on the internet can access it. This can be risky if sensitive information, such as API keys, database passwords, and access tokens, is exposed in your code (attackers could exploit these credentials, gaining unauthorized access to systems, databases, or services). 

2. Outdated or vulnerable third-party libraries: Nowadays, there’s little need to create code from scratch when you can integrate a third-party library that provides the functionality you want. The downside to incorporating third-party libraries in your code is that you risk introducing vulnerabilities in your software. 

3. Insider threats or unauthorized changes to repositories: Mistakes are inevitable when humans are involved. A colleague with write access to your repository can make a commit or pull request that introduces vulnerable code to the codebase. 

Fortunately, these problems are relatively easy to prevent:

• Use secrets detection tools to catch exposed credentials: Code review tools like Codacy offer hardcoded secrets detection, which scans your codebase in real time to identify and remove sensitive data embedded directly in your source code.
  
  
• Employ Software Composition Analysis (SCA) to identify vulnerabilities in dependencies: Scan your entire software supply chain using an application testing tool that performs SCA (e.g., Codacy) so you can identify vulnerabilities in third-party code and eliminate them.
  
  
• Enforce multifactor authentication and access controls for repository access: Secure your codebase by enforcing role-based access controls (RBAC) and multifactor authentication (MFA), conduct regular code reviews, and monitor for suspicious activity.

Build Stage

Your source code is ready and collected. The next step is transforming it into a deployment artifact, which could be a binary, executable, or package. This happens in the build stage of the CI/CD pipeline.

The build process will vary depending on the application type. In web apps, for instance, building typically involves minifying and bundling JavaScript code. Whereas a mobile application may need platform-specific builds for iOS and Android. The source code will undergo more tests in this stage to ensure the built code is error-free.

If the build process completes successfully, the build tool produces an artifact (or multiple artifacts) that can be deployed in the following stages. But if the tests or the build process fails, the build “breaks,” and pipeline execution grinds to a halt (developers are notified and often given a reason for why the build process failed). 

Common security risks associated with the build stage of the CI/CD pipeline:

1. Insecure or misconfigured build environments: Deploying with suboptimal or default configurations might present threat actors with loopholes to steal sensitive information. In 2017, a misconfigured build environment in Equifax's Apache Struts led to a breach that exposed 147 million people’s data.

2. Injection attacks through build scripts or third-party tools: Code injection occurs when malicious code is inserted into the CI/CD pipeline, often to execute harmful build scripts that expose sensitive information. Threat actors can also compromise software by injecting malicious code into an insecure third-party library.

3. Use of untrusted plugins and dependencies: Many modern applications rely on third-party libraries, plugins, or frameworks to add functionality or speed up development. However, if these dependencies are not carefully vetted, they can introduce vulnerabilities into the build process. 

These security risks can be mitigated using a combination of various automated testing tools and security practices:

• Integrate Static Application Security Testing (SAST): A SAST tool scans an application's source code, byte code, or binaries to identify security vulnerabilities without running your application.
  
  
• Secure build environments: Use container isolation and network segmentation to protect against unauthorized access and reduce the attack surface.
  
  
• Audit and validate plugins: Again, scan the entire software supply chain (libraries, frameworks, plugins, etc.) using software composition analysis to verify that they are free from security vulnerabilities and are regularly updated. 

Test Stage

In the “test” stage, the built code goes through a comprehensive series of (automated) tests that thoroughly verify its correctness and quality before it reaches end-users. This is a critical phase because, without testing, you can’t know for sure if your code will perform as expected.  

Tests conducted during this stage can include:

• Integration tests: Verifies that the various application components interact well with one another and work seamlessly together.
  
  
• Functional tests: Checks the user interface to ensure that the application behaves as expected from the end-user perspective.
  
  
• Performance tests: The app undergoes tests to ascertain if it can handle the expected number of users, respond quickly, and remain stable even under stress. 
  
  
• Security tests: Scans the app to identify potential vulnerabilities or security risks that may prove costly in production.

Common risks seen in the build stage:

1. Insufficient or incomplete test coverage for security vulnerabilities: Code coverage runs alongside your test suite to monitor parts of the code covered by the tests. Test coverage will go a long way in sniffing out vulnerabilities that may have otherwise slid through the pipeline and into production undetected.

2. Neglecting runtime testing for dynamic code: Dynamic code often has different entities that interact with one another, such as external APIs, services, or libraries loaded during runtime. Incorporating runtime testing in your testing strategy will enable you to verify that these interactions work correctly under all conditions.

How to resolve them:

• Use Dynamic Application Security Testing (DAST): This outside-in testing strategy analyzes web and mobile applications for vulnerabilities by simulating attacks, allowing you to uncover vulnerabilities that many have sneaked past your other security defenses.
  
  
• Automate security-focused tests and expand coverage: If you have any legacy codebase, expand code coverage to cover them and monitor your coverage level frequently (e.g., on every commit or pull request).

Deploy Stage

The “deploy” stage is the final part of the CI/CD pipeline. Once the built software passes all tests, the pipeline automatically releases it into the production environment (in your server or cloud platform). 

At this point, the code has “gone live” and is accessible to end users. Post-deployment or smoke tests are commonly performed immediately after deployment to the production environment to ensure the application works as expected.

The deployment process may vary from one environment to another and primarily depends on the application type. For some apps, you’ll need to spin up a virtual machine, for example, in a cloud platform such as Azure or IBM Cloud. Some require updating a mobile app through an app store or transferring files to an FTP server.

Common security risks encountered in the deployment stage of the CI/CD pipeline are:

1. Misconfigured Infrastructure as Code (IaC) templates: Poorly configured IaC template code and its dependencies may contain defects that could unintentionally jeopardize the infrastructure or provide a skilled attacker with an opportunity to exploit the system.

2. Lax access control policies: Hackers can exploit overly permissive access policies in servers and cloud storage platforms to launch attacks or steal sensitive information, such as credit card information, state files, and other cloud credentials. 

3. Deployment of insecure apps to production: The deployed app might contain vulnerabilities even after undergoing a thorough testing process (this is because some vulnerabilities only emerge when the software is live in production).

Here are some practices for mitigating these security risks: 

• Scan your IaC templates: Check for issues like open ports or overly permissive roles using an application testing solution with robust and comprehensive IaC testing capabilities, like Codacy.
  
  
• Use blue-green or canary deployments to reduce risk during rollouts: Opt for the canary deployment strategy if you prefer a more gradual rollout process (i.e., first test on a small subset of users before full release). Blue-green is best for straightforward, low-risk updates that require fast rollbacks. It utilizes two identical production environments to reduce downtime during deployment. 
  
  
• Enforce policy-as-code to maintain compliance and security standards: Similar to infrastructure-as-code (IaC), policy-as-code is an approach that treats policies as regular program code. This allows system administrators to automate critical governance tasks, including policy deployment, enforcement, and auditing.

How Codacy Can Help You Secure Your CI/CD Pipeline

Codacy is an all-in-one DevSecOps solution that offers everything you need to secure your CI/CD pipelines from start to end: SAST, SCA, IaC scanning, secret detection, DAST, pen testing, and CSPM (coming soon). 

Codacy provides extensive coverage throughout the application stack, detecting vulnerabilities in code, dependencies, containers, and infrastructure. Its scalable architecture allows it to handle large codebases and extensive security data, making it ideal for organizations of all sizes. 

Get started for free today and take the first step toward securing your CI/CD pipelines.