Continuous Integration and Continuous Deployment (CI/CD) pipelines have become indispensable for development teams. However, what many organizations fail to recognize is the significant risk these pipelines pose if not properly constructed and managed, whether in the cloud or on-premises. By definition, a CI/CD pipeline offers elevated access for remote code execution of potentially risky operations, making it a critical area for implementing robust risk mitigation strategies. This exposure not only impacts the primary assets of your R&D team but can also jeopardize production environments that house sensitive customer data. Ignoring these vulnerabilities can lead to potentially disastrous outcomes. In this article, we explore key strategies for managing these risks effectively.
Understanding the Risks
When it comes to CI/CD pipelines, there are two pivotal assets that demand rigorous protection:
Source Code: One of the most alarming threats recently is the supply chain attack on GitHub accounts, where attackers gain control and lock organizations out of their source code repositories. Even if lockout doesn't happen, leaking your source code on it's own can have severe consequences. Recovering from such an event can immobilize your R&D for months, depending on the scale and severity.
Customer Data: The secrets utilized in your pipeline can be exploited to compromise the integrity of the data you manage within your software solution, thereby severely affecting your production environments. The extent of this exposure depends on how you isolate pipeline processes.
Preparing for a worst-case scenario is imperative to ensure continuous operation, even if these assets are compromised. But our focus here is not on business continuity plans. We would rather highlight proactive measures to avoid such incidents in the first place.
Secrets Handling
Embedding secrets directly in your source code is a ticking time bomb. Even in private repositories, this practice is fraught with risk; it's a matter of when, not if, a breach occurs. It is crucial to decouple pipeline secrets from source code and manage them through a secure secrets management tool. GitHub, for instance, offers a basic secrets manager, but for advanced requirements - such as secret rotation and access logging - we found that tools like Azure Key Vault and AWS Secrets Manager provide vital features, ensuring enhanced security and transparency.
Using Community/External Scripts
External scripts, known as "Actions" in GitHub, are commonly used in CI/CD workflows. However, many other platforms offer limited control over versioning and reviewing these scripts. At OneRingCI, we adhere to a strict policy of only using scripts from trusted authorities like Azure, AWS, Docker, and GitHub. We also maintain a blacklist of deprecated or sub-optimal scripts. Every Action is audited and analyzed depending on the context before we make a decisions whether to use it or create a custom one where we have more control. This due diligence approach includes periodic reviews and strict version control to prevent unauthorized updates. For heightened security in GitHub, we recommend referencing external actions via the full SHA of the commit, avoiding mutable tags and branches.
Build Runners/Agents
Deploying code and artifacts on a virtual machine with access to your secrets can be daunting. Build runners, particularly those set up initially and rarely updated, pose significant risks. Consequently, the industry is shifting from long-lived to short-lived ephemeral agents, which are provisioned on demand and disposed of immediately after use. Containerization facilitates this transition by enabling rapid instance warmup, often in seconds. At OneRingCI, we maintain Docker containers for Linux, macOS, and Windows for different scenarios, updating dependencies monthly to incorporate the latest security patches. Furthermore, we often encourage and facilitate the restriction of this infrastructure into a dedicated private network.
Principle of Least Privilege (PoLP)
Though it may seem obvious, it's crucial to restrict CI/CD pipeline access to only those who genuinely need it. With the high stakes involved in executing scripts that impact artifacts and production environments, limiting changes to a trusted group of individuals well-versed in the associated risks is essential. However, platforms don't always provide the contextual granularity that an organization needs and sometimes additional controls are necessary. For example, at OneRingCI we utilize the CODEOWNERS mechanism, combined with pull-request validation to control alterations to pipeline changes since GitHub on it's own doesn't always have enough flexibility.
Logging and Monitoring
Finally, implementing centralized monitoring and logging is vital for maintaining security. In the event of a breach, audit trails serve as the cornerstone for forensic analysis. Ensure that every pipeline decision point logs details verbosely so each step can be traced thoroughly. Logs also offer insights into the CI/CD pipeline's health and performance, so regular reviews and audits are advisable. At OneRingCI, we leverage AI models to distill critical information from logs, making log reviews an essential component of our managed service.
SSO with enforced MFA
Slightly off-topic, but a honorable mention. Single sign-on with enforced multi-factor authentication is an organization-wide policy. If setup properly with automation during user on-boarding and off-boarding it dramatically reduces multiple risks.
In Conclusion
Securing your CI/CD pipeline requires a multi-faceted approach that addresses potential vulnerabilities at every stage. If no policies are in place here's a high-level plan that you can follow:
Asses your risks and play out worst case scenarios;
Standardize how you manage pipeline secrets;
Review scripts on a regular cadence and implement a versioning strategy;
Maintain a user access matrix based on needs;
Implement logging and monitoring to gain transparency;
Utilize SSO and MFA across the whole organization.
By implementing these best practices, you can significantly mitigate risks and protect your organization's valuable assets. As every organization is different, proper risk analysis in the current context is a great starting point.
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