Infrastructure as Code (IaC) security: How to avoid risky bugs in Terraform and Ansible?

The Infrastructure as Code (IaC) approach, or infrastructure as code, is one of the pillars of the DevOps and cloud revolution. The idea is simple and brilliant at the same time: instead of configuring servers, networks and databases manually, by clicking on the console, we describe the entire infrastructure in the form of code, using tools such as Terraform, Ansible or CloudFormation. This gives great advantages: automation, repeatability, versioning and the ability to review changes, just like regular application code. It’s an approach that allows complex environments to be built and managed at a pace and scale that was unattainable a decade ago.

However, this enormous power brings with it an equally enormous responsibility. In the IaC model, one line of code can create a hundred virtual machines. And one erroneous line of code can create a hundred VMs with a critical security vulnerability, replicating a single bug on a massive scale. An unprotected port, overly broad permissions or a password written in code – in the world of IaC, such mistakes are no longer isolated incidents, but systemic risks that can be deployed to production in minutes. Securing the code that builds your infrastructure thus becomes as important as securing the infrastructure itself.

What is Infrastructure as Code (IaC) and why has it become a standard in DevOps?

Infrastructure as Code (IaC) is the practice of managing and provisioning (creating) IT infrastructure through configuration files in the form of code, instead of manual configuration or interactive tools. In this model, the definition of servers, networks, databases, load balancers and other components is written in text files that can be stored in a version control system (such as Git), just like application code.

IaC has become an absolute standard in modern DevOps teams and cloud environments for several key reasons:

• Automation and Speed: IaC allows fully automated creation and modification of entire, complex environments with a single command. This reduces deployment time from days or weeks to minutes.
• Repeatability and Consistency: The code is a guarantee that every environment – development, test and production – is created in exactly the same, repeatable way, eliminating problems caused by “configuration drift.”
• Versioning and Audability: storing infrastructure code in Git gives a complete history of changes. You know who made modifications, when and why, making it easier to audit and undo erroneous changes.
• Collaboration: code can be reviewed (code review) by other team members, allowing you to catch bugs and share knowledge, just like in software development.

What are the most common security mistakes made in IaC code?

Despite its huge advantages, IaC, if not used thoughtfully, can become a powerful tool for automating… deployment of security vulnerabilities. Bugs that once affected a single, manually configured server can now be replicated to hundreds of machines. Some of the most common and dangerous errors include:

• Storing “secrets” in code (hardcoded secrets): Placing passwords, API keys, tokens or SSH keys permanently in IaC code. If such code ends up in a public repository, it is equivalent to giving the keys to the kingdom.
• Overly permissive IAM roles: Creating roles and access policies (e.g., in AWS IAM) that grant virtual machines or services much broader permissions than they need to operate.
• Unsecure networks (insecure networking): Define security groups or firewall rules that open sensitive ports (e.g. RDP, SSH, database ports) to the entire Internet (0.0.0.0/0).
• No encryption: Failure to enable encryption for data trays (e.g. S3 buckets), disk volumes (e.g. EBS) or databases.
• Lack of logging and monitoring: Default disabling or misconfiguration of event logging for key cloud services, making it impossible to detect and analyze an attack.

What risks are posed by “secrets” (passwords, API keys) stored in the IaC code?

Storing “secrets” permanently in code (hardcoding secrets) is one of the most serious and unfortunately still common mistakes in IaC practices. This involves putting sensitive data, such as database passwords, cloud API access keys or SSH private keys, directly into Terraform configuration files (.tf) or Ansible playbooks (.yml). This code is then often uploaded to a central repository (e.g. GitHub, GitLab).

The risks are enormous. Even if the repository is private, the entire development team usually has access to it, which violates the principle of least privilege. The real disaster, however, occurs when the repository is mistakenly made public, or when one developer’s account is compromised. Attackers, gaining access to the code, immediately find all the “keys to the kingdom” given on a platter. Automated bots are constantly scanning public repositories for just such leaks.

The correct approach is to completely separate secrets from code. Secrets should be stored in dedicated, secure secret management (secrets management) systems, such as HashiCorp Vault, AWS Secrets Manager or Azure Key Vault. At runtime, IaC code should dynamically and securely retrieve needed secrets from such a system, never storing them in plaintext.

How can security flaws be detected in IaC code before deployment to production?

The key to securing IaC is to implement a “shift-left” philosophy, i.e. detecting problems at the earliest possible stage, before a dangerous configuration even hits the production environment. Instead of waiting for an audit of the running infrastructure, the very code that creates it should be analyzed and audited. Specialized tools for static analysis of IaC code serve this purpose.

These tools work similarly to SAST scanners for application code. They analyze the configuration files of Terraform, Ansible, CloudFormation or Kubernetes to look for patterns that indicate potential security vulnerabilities. The IaC scanner can automatically detect that:

• The security group is configured to allow SSH access from all over the Internet.
• The S3 resource does not have encryption enabled.
• There is a permanently stored API key in the code.
• The IAM role grants administrator privileges (“*:*”) to all resources.

Among the most popular open-source tools in this category are Checkov, Terrascan, tfsec or KICS. They allow early detection of bugs and provide the developer with immediate feedback, allowing him to fix the problem before the code leaves his local environment.

How to integrate IaC scanning into the CI/CD pipeline to automate control?

Running IaC scanners manually is better than nothing, but the true power of this approach is only revealed when it is fully automated and integrated into the CI/CD (Continuous Integration/Continuous Delivery) pipeline. The goal is to create an automated “quality gate” for security that prevents IaC code that does not meet defined standards from being deployed into production.

Integration most often takes place at two levels:

1. At the code repository level (e.g. GitLab, GitHub): The IaC scanner can be configured as an automatic action (e.g., GitHub Action) that runs every time a new change is attempted (pull/merge request). If the scanner detects critical bugs, it can automatically block the inclusion of that change in the main code branch and publish its results as a comment to the developer.
2. At the deployment pipeline level: Even if the change is approved, the scanner is restarted as one of the steps in the pipeline, just before the terraform apply or ansible-playbook command is executed. If the latter scan shows any problems, the entire pipeline is stopped and the deployment is blocked.

This integration ensures that every single change to the infrastructure is automatically verified for security, without slowing down the team or relying on unreliable human memory.

How does nFlo help secure the entire Infrastructure as Code lifecycle?

At nFlo, we strongly believe in the shift-left philosophy and understand that a secure cloud infrastructure starts with secure code. Our DevSecOps and cloud security services are designed to help organizations secure the entire IaC lifecycle, from code development to deployment and monitoring.

Our approach begins with an audit of IaC code and CI/CD processes. Our experts perform an in-depth analysis of existing Terraform, Ansible or CloudFormation repositories, identifying security flaws, configuration weaknesses and deviations from best practices. We also analyze existing CI/CD pipelines, looking for opportunities to integrate and automate security controls.

Based on the audit, we actively assist in the design and implementation of secure CI/CD pipelines. We support clients in selecting and integrating appropriate IaC scanning tools, creating automated quality gates that become an integral part of the development process. We also provide dedicated training for DevOps teams and developers, teaching them how to write secure IaC code and how to use new tools. Our goal is not only to fix existing problems, but more importantly to build a sustainable culture and competence in the organization to create secure infrastructure in an automated way.