What is a Cloud Firewall? A Comprehensive Guide for IT Leaders

Cloud computing has become critical to a company’s ability to scale its applications and services. As more sensitive data and functionality move to the cloud, cloud security becomes a more critical component of a comprehensive corporate cybersecurity strategy. Cloud firewalls provide vital security capabilities to prevent cyber criminals from exploiting cloud-based applications and data.

Understanding Cloud Firewalls

Firewalls have the critical role of defining network boundaries and the types of traffic permitted to cross those boundaries. Cloud environments sit outside the traditional network perimeter and need their own defenses against potential attacks. Cloud firewalls sit between an organization’s cloud infrastructure and its users, protecting cloud assets against potential exploitation and unauthorized access.

While cloud firewalls perform the same role as a traditional network firewall, they do so in a very different way. Some of the key features of cloud firewalls include:

  • Cloud-Native Protection: Cloud firewalls are offered as a Firewall-as-a-Service (FWaaS) model. Instead of deploying a physical or virtual cloud appliance, companies subscribe to a cloud firewall service that protects their cloud-based assets.
  • Traffic Inspection and Filtering: Like traditional network firewalls, FWaaS offerings inspect network traffic and filter it based on network and application-specific rules. They also include next-generation firewall (NGFW) capabilities, such as intrusion prevention system (IPS) to detect and block advanced threats.
  • Virtual Patching: FWaaS offers virtual patching capabilities as the security policy enforcement layer that analyzes transactions and intercepts attempts to exploit security flaws in vulnerable cloud applications.

Benefits of Cloud Firewalls for Enterprises

Cloud firewalls offer various benefits when compared to traditional network firewalls, including:

  • Improved Visibility and Control: Cloud firewalls see all traffic entering and leaving the corporate cloud environment. With application awareness, they can identify the various types of applications and apply application-specific security controls.
  • Access Management: FWaaS enables granular access management for cloud-based resources and endpoints. Companies can control access to cloud resources based on zero trust principles.
  • Secure Cloud Adoption and Migration: Securely moving to the cloud can be tricky since on-prem security solutions rarely work effectively in cloud environments. Cloud firewalls enable an organization to consistently apply the same security and access controls across their entire IT infrastructure.
  • Scalability and Flexibility: Cloud firewalls’ cloud-native protection offers greater scalability and flexibility than traditional, appliance-based solutions. This enables them to adapt to meet traffic changes due to evolving user demand or new applications.
  • Improved Security Performance: Cloud firewalls’ cloud-native scalability also positively impacts their performance. With the ability to deploy additional resources as needed, they offer lower latency when dealing with traffic surges or computationally intensive operations such as TLS inspection.
  • Cost Efficiency: FWaaS operates under a subscription-based billing model, meaning that companies only pay for what they need. This can offer significant cost savings when compared to traditional firewalls where a company needs to purchase appliances capable of handling potential surges in traffic.
  • Simplified Management: Cloud firewalls centralize security management in a single location. This makes it easier for an organization to configure, monitor, and manage security infrastructures for complex, multi-cloud environments.

Cloud Firewalls in a Zero Trust Security Model

The zero trust security minimizes an organization’s cybersecurity risk by eliminating implicit trust for all users. Firewalls are a core component of a zero trust infrastructure, supporting many of the model’s core principles, including:

  • Identity Verification: Cloud firewalls have visibility into all traffic passing through them. When integrated with a zero trust identity and access management (IAM) solution, they can explicitly verify a user’s identity and context, and whether they are authorized to access a particular resource.
  • Least Privilege Access: The zero trust security model mandates that every access request be managed based on zero trust access controls. Granular policies implemented on cloud firewalls can ensure access is granted with only the minimum level of privileges required to ensure productivity.
  • Micro-Segmentation: Microsegmentation creates smaller, trusted segments within the organization’s network to protect specific applications and resources. With cloud firewalls and microsegmentation, an organization can inspect all traffic, preventing data exfiltration and lateral movement through the corporate cloud.

Best Practices for Cloud Firewall Deployment and Management

Cloud firewalls are the cornerstone of a cloud security architecture. Some best practices for deploying and managing these solutions include:

  • Firewall Configuration and Hardening: A FWaaS offering is managed by the service provider, who has implemented most of the necessary patching and hardening. However, the customer may need to set certain configuration settings to match the needs of their cloud infrastructure.
  • Rule Management: Firewall rules determine the types of traffic permitted to pass through the firewall. Firewall rules should be carefully defined to ensure that they meet business needs and should be regularly reviewed and updated.
  • Security Integration: A cloud firewall is only one component of an organization’s cloud security infrastructure. Integration with other cloud security tools enables these tools to leverage firewalls’ deep visibility into network traffic to block malicious traffic flows that place corporate applications at risk.
  • Account Management: Access to a firewall’s management portal provides an attacker with extensive access to an organization’s environment. All firewall admin accounts should have strong passwords and use multi-factor authentication (MFA).
  • Network Segmentation: Firewalls should be configured to implement network segmentation and microsegmentation. This helps to protect against lateral movement and enables the enforcement of zero trust access controls.
  • Monitoring and Auditing: Cloud firewalls should be continually monitored and regularly audited. This helps identify potential attacks and ensure that rules and policies continue to protect a rapidly evolving cloud infrastructure.

Cloud Firewalls in a SASE Framework

Secure access service edge (SASE) converges network security functions in a single, cloud-native solution. The security-focused component of SASE — also known as Security Service Edge (SSE) — includes several functions, such as FWaaS, ZTNA, CASB, and SWG.

By integrating cloud firewalls with other SASE capabilities, SASE offers improved performance and security when compared to standalone solutions. By eliminating the need for each tool to perform its own decryption, SASE improves performance and decreases latency without compromising on security.