Infrastructure as code (IaC) has changed how we deploy and manage our cloud infrastructure. Instead of having to manually configure servers and networks with a large operations team, we can now define our service architecture through code. IaC allows us to automate infrastructure deployment, scale our entire fleet of servers, document a history of changes to our architecture, and test incremental changes to the network. It’s no wonder IaC has become the primary way teams and companies set up and manage their cloud services.

However, while IaC brings many benefits, it’s not without security concerns. Let’s look at the top 5 security concerns for IaC and the best practices we can implement to mitigate them. 

1. Misconfigurations in IaC templates

One of the biggest security concerns for IaC is misconfigurations in the template. IaC template code and dependencies can contain bugs, which may inadvertently compromise the infrastructure or present a knowledgeable attacker with a means of exploiting the system. 

For instance, suppose an IaC template unintentionally includes hard-coded username and password credentials for a database containing sensitive user data, such as financial details or personal identifiable information (PII). An attacker who gains unauthorized access to this template could view the data and manipulate the database. 

Similarly, imagine an IaC template with a hard-coded IP address to a critical server. The server can become the target of a denial-of-service (DoS) attack, and it could be difficult to respond quickly and update the infrastructure. Using parameterized input features or environment variables is essential to separate credentials and sensitive information from the template code.

Another example is using outdated or deprecated IaC frameworks and other third-party dependencies. Attackers may discover new flaws in older code versions, enabling them to exploit otherwise-unknown misconfigurations. The risk becomes even greater when the same IaC templates are shared across different environments, making a single misconfiguration much more impactful. It’s important to regularly maintain and update code and carefully vet third-party dependencies to ensure they’re updated.

To further secure IaC templates, we should implement secure coding practices, including writing robust IaC code that includes input and parameter validation in functions and using testing frameworks and version control to validate and track changes to the code to handle errors quickly. We should also verify that the template functions correctly during deployment and teardown to prevent unexpected costs from improperly removed services. 

2. Insecure storage and transmission of secrets

Secret management is another critical security concern in IaC. Passwords and API keys pose a risk if exposed. Malicious actors can use other sensitive information, like webhook URLs or IP addresses, to spam or deny resources and bring down a service or network. 

Even read-only access to an IaC template can provide attackers with valuable insight into the infrastructure, helping them identify potential misconfigurations. This makes planning and executing targeted attacks easier. 

Fortunately, IaC frameworks and cloud platforms allow us to store and use these secrets securely. For example, Terraform Cloud provides a secrets management feature to ensure these sensitive values are properly encrypted and stored. And cloud services often automatically provide secrets — such as access keys and database connection strings — as environment variables, so we can override them with our own values when developing locally.

3. Misconfigured access control policies and configuration drift

The OWASP Top 10, a globally recognized document for web application security, rates insufficient access control and cloud misconfigurations as significant concerns. 

Hackers can exploit overly permissive access policies for resources, like servers and cloud data storage, to execute attacks or retrieve private information. Misconfigured AWS S3 buckets have been responsible for leaking sensitive data like credentials, PII, and credit card information.

Attackers can exploit configurations through open network ports, unrestricted rate limits, or unencrypted data in transit or at rest. They can then take advantage of these misconfigurations to gain unauthorized access, steal sensitive data, or disrupt services. 

Configuration misconfigurations can also emerge less visibly over time through configuration drift, which occurs when infrastructure changes aren’t documented or properly managed. For example, you may apply system patches without recording changes, or engineers may log in to investigate issues, make manual changes, and forget to revert them. These actions can make it difficult to identify and address potential risks outside the view of the IaC template, leaving the system exposed to threats.

IaC templates help mitigate some of these risks through automation and version control, but they don’t solve everything. It’s frustrating to wait a long time for an IaC template to deploy and find out that it failed due to a permissions error, so it might be tempting to use a full-access policy to fix it. But this shortcut introduces misconfigurations that are otherwise preventable. 

To ensure proper access control, always follow the principle of least privilege (PoLP) and limit permissions as much as possible. Grant access only when needed, utilizing strictly defined control policies, auto-rotating keys, and temporary access roles. 

Security auditing tools like Snyk Infrastructure as Code and Snyk Container can also help scan and monitor infrastructure, automating the process and making it easier to maintain secure configurations and access policies.

4. Insecure state files

Since most IaC frameworks generate state files to record the current state of the deployed infrastructure, keeping them secure and in sync with the actual state of the cloud is crucial. Plaintext state files can contain detailed information about the security of cloud resources, and the only way to protect this information is to encrypt the state file and secure access to it. 

If we lose this state file, we no longer have a record of the infrastructure state deployed using the IaC templates/code. Such a loss would necessitate manually importing existing cloud resources back into the persistent state file so that future IaC management isn’t affected. 

If an IaC is managed in an automated CI/CD pipeline, losing the state file could result in the destruction or creation of resources, causing system downtime or data loss. Similarly, a corrupt or out-of-sync state file can quickly become messy when manually mapping resources and piecing things back together. 

We can avoid getting into this situation by taking some simple precautions:

• Store the state file remotely on the cloud to be easily shared and backed up.
• Enable versioning to recover it in case the file becomes corrupted.
• Use a file-locking mechanism so that only one user can deploy and change the state file at any time.
• Encrypt the file when storing it so that an attacker can’t decrypt it even if they gain access to it.
• Restrict user access to the state file so that only the team has access to the file. Even when secrets are securely stored and kept out of IaC templates, state files may contain them in plaintext, so it’s essential to encrypt these files and limit access to avoid leaking secrets.

5. Lack of testing and validation

IaC templates that aren't thoroughly tested and validated can potentially result in insecure deployments or misconfigurations, allowing attackers to compromise the infrastructure.

By making testing and validation an integral part of our IaC development workflow, we can identify, mitigate, and minimize risks early in the process and proactively secure our infrastructure. 

Consider the following questions when testing and validating an IaC:

• Did the IaC template deploy successfully?
• Do the access controls and configurations align with the code?
• Are resources correctly mapped and referenced?
• Is server activity properly monitored and logged?
• Can the infrastructure handle the required load traffic?

Best practices for testing and validating IaC follow the same general principles as for all code. Implement a code review process within the team. Test the code in a staging environment before deploying it to production. Use linting tools to detect syntax and formatting errors and write unit tests — checking resource names or identifiers, for example. Scan high-level IaC code from tools like Pulumi with automated Static Application Security Testing (SAST) tools like Snyk Code. 

Ultimately, the best way to securely develop, test, and validate IaC is to integrate security into the development process. One way to do this is with Snyk Infrastructure as Code, a specialized tool for enhancing the testing and validation of IaC. It seamlessly integrates with development tools and workflows, enabling real-time and continuous secure IaC development. 

Snyk Infrastructure as Code scans code for potential misconfigurations or policy violations and provides actionable insights and advice to address the issues found. We can leverage this information to improve the overall security posture of our IaC and ensure that it’s compliant. 

Conclusion

This article explored five security concerns when using IaC. We also learned ways to address them, such as following the principle of least privilege, applying secure coding practices, and integrating security tools into the process.

The importance of implementing best practices to keep IaC secure can’t be overstated — particularly when we consider the potential consequences of insecure IaC. By neglecting concerns such as hard coded credentials, mismanaged secrets, and configuration drift, we risk negating the benefits of IaC, resulting in potential data breaches, unauthorized access, and disruption of critical services.

By proactively integrating security into the IaC development process and applying best practices, we can effectively mitigate risks, protect our infrastructure, and guard our businesses and customers.