In today’s cloud environments, every entry point is a potential vulnerability. Attackers don’t announce themselves at the front door - they quietly probe for weaknesses, looking for any oversight to exploit. The line between innovation and vulnerability has never been thinner. For organizations leveraging Kubernetes, securing ingress - the critical entry point for traffic into clusters - is not just a technical task. It’s a business-critical defense mechanism and a foundation for operational security.
At Cyngular, we understand that protecting the perimeter of your cloud infrastructure demands more than tools. It requires precision, automation, and a clear Zero Trust strategy. Here’s how redefined Kubernetes ingress security can stay ahead of evolving threats while maintaining the agility needed to support modern operations.
Ingress Management: A Controlled Gateway
At the heart of our cloud security strategy is Ingress NGINX, a powerful Kubernetes ingress controller that governs and enables traffic into our clusters. Acting as a controlled gateway, Ingress NGINX ensures requests are routed efficiently to their intended services while preventing unauthorized access when configured correctly.
To protect data in transit, we integrate Cert-Manager for the automated provisioning and renewal of SSL/TLS certificates. This ensures all ingress traffic is encrypted without requiring manual intervention, reducing operational overhead and eliminating the risk of expired certificates. Together, these tools form the backbone of a secure and automated ingress management system.
Load Balancers and DNS: Precision at the Edge
The load balancers and DNS configurations form the first line of defense at the edge of our cloud infrastructure. All required external interactions with sensitive services are tightly controlled through dynamic IP whitelisting, which is managed through automation.
To achieve this, a custom controller has been developed alongside the use of open-source tools such as Stakater Reloader (https://github.com/stakater/Reloader) and Keel (https://keel.sh/). These tools update ingress annotations based on changes detected in AWS Secrets Manager, ensuring real-time adjustments to reflect operational needs.
This precision-driven approach ensures that only explicitly authorized traffic reaches the desired systems. By dynamically adapting to shifting requirements, we enable high security without sacrificing seamless developer access when needed.
The Silent Risk: Why Ingress Security Matters
Ingress points in Kubernetes are often overlooked in the rush to deploy applications at scale. However, these entry points determine what traffic is allowed to interact with your clusters and services. Without proper management, attackers can:
- Exploit Misconfigurations: Unsecured ingress resources can unintentionally expose internal services to the public internet.
- Inject Malicious Traffic: Unfiltered ingress points create opportunities for attackers to introduce harmful payloads.
- Bypass Security Measures: Vulnerable ingress configurations can allow attackers to circumvent firewalls and other defenses.
For organizations handling sensitive data, such as cybersecurity platforms or SaaS providers, even a minor lapse in ingress security can lead to:
- Unauthorized access to critical services.
- Data exfiltration via malicious traffic.
- Regulatory violations due to the failure to secure sensitive assets.
Securing Kubernetes ingress is about more than mitigating threats, it’s about ensuring customer trust, protecting data integrity, and supporting operational resilience.
Automation-Driven Security
Manual configurations are prone to human error. In the fast-moving world of Kubernetes, even a small misstep can result in costly breaches. That’s why automation lies at the core of our security philosophy. Every aspect of ingress security, from managing rules to updating certificates and IP whitelists - is scripted and orchestrated to:
- Respond to changes in near real-time.
- Enforce consistency across environments.
- Minimize the risk of misconfigurations.
By automating security workflows, teams can focus on innovation rather than repetitive tasks, ensuring both agility and reliability.
An Attacker’s Perspective: How Ingress Vulnerabilities Are Exploited
Attackers view Kubernetes ingress points as valuable targets for initial access into an organization's infrastructure. A single misconfiguration, such as an overly permissive ingress rule, can provide them with a foothold into the cluster, from which they can launch further attacks.
For example, an attacker might exploit a misconfigured ingress controller with a publicly exposed service. This can allow unauthorized access to an internal API endpoint or backend application. Here’s how such an attack could unfold:
- Reconnaissance: The attacker scans for exposed ingress points or services using tools like Nmap or Shodan. They identify ingress resources with overly broad access rules (e.g., allowing all incoming traffic or exposing sensitive internal services).
- Exploitation: Once a vulnerable ingress is discovered, the attacker sends malicious traffic to the exposed service. For instance, they might exploit a weak API endpoint to upload malicious payloads or trigger unauthorized actions.
- Lateral Movement: After gaining access to the cluster, the attacker leverages compromised credentials or weak service-to-service communication rules to move deeper into the infrastructure. They may gain access to sensitive databases, internal APIs, or even cloud environments connected to the cluster.
- Impact: The attacker could exfiltrate sensitive data, disrupt services, or deploy ransomware to lock down the organization’s Kubernetes infrastructure.
Real-world Example
A well-known Kubernetes ingress attack involves abusing overly permissive IP whitelisting configurations. If ingress rules allow a wide range of IP addresses instead of restricting access to specific trusted IPs, attackers can impersonate a legitimate user, bypass defenses, and exploit backend services.
Steps Taken by the Attacker in Such Scenarios:
- Identify ingress resources with default configurations or insufficient IP whitelisting.
- Spoof IPs that fall within the allowed range of ingress rules.
- Access internal endpoints, gather data, or inject malicious requests to compromise services.
Attack Tactics, Techniques, and Procedures (TTPs) and MITRE ATT&CK Mapping
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Initial Access (T1190): Exploit Public-Facing Applications
Attackers exploit vulnerabilities or misconfigurations in publicly accessible applications, such as ingress resources and exposed APIs, to gain unauthorized access. Providing a foothold into the target environment.
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Discovery (T1018): Remote System Discovery
Once inside the environment, attackers scan for exposed endpoints, services (leading to pods), or internal resources. They identify ingress routes, leading in turn to backend services, and potential paths for lateral movement by exploring the network topology.
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Credential Access (T1078): Valid Accounts
Attackers use stolen or spoofed credentials to bypass security controls, such as ingress whitelists, and gain legitimate access to systems. These accounts are often abused to move stealthily through the infrastructure.
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Lateral Movement (T1210): Exploitation of Remote Services
After establishing a foothold, attackers exploit weak service-to-service communications or ingress misconfigurations to pivot and access other internal systems or sensitive data stores within the network.
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Impact (T1486): Data Encrypted for Impact (Ransomware)
Attackers encrypt critical data, systems, or applications to disrupt operations, demanding ransom payments in exchange for decryption keys. Alternatively, they may exfiltrate sensitive data to sell or blackmail the organization, data like EBS volumes mounted to the cluster, configmaps, and secrets.
Closing Unnecessary Access Points
An open door is an invitation for trouble. Following Zero Trust principles and the principle of least privilege, ensuring only essential ingress points remain open while all unnecessary access points are closed by default. This minimizes the attack surface and simplifies monitoring and enforcement.
This is achieved by leveraging NGINX Ingress configurations, specifically the `externalTrafficPolicy: Local` setting, to enforce strict access controls. This configuration allows ingress controllers to pass client request IP addresses, making IP whitelisting possible for federated access.
Implementation Steps:
- Configure the ingress controller with the `externalTrafficPolicy: Local` setting. For more details, see (https://blog.getambassador.io/externaltrafficpolicy-local-on-kubernetes-e66e498212f9).
- Add the “nginx.ingress.kubernetes.io/whitelist-source-range” annotation to Ingress Resources for implementing IP-based access control
- When using tools like Argo CD to manage Kubernetes resources, make the ingress whitelist annotations dynamic by using Diff Customization for argo application resource.
Cyngular Security's CIRA Platform
To further secure your cloud environment, consider integrating Cyngular Security's CIRA platform. It enhances your security posture by providing advanced investigation and response capabilities, enabling your team to address threats swiftly and effectively. By adopting Cyngular Security's CIRA, you empower your organization with proactive and automated security measures that protect your cloud assets.
Get a Free Breach Assessment
Protect your cybersecurity infrastructure with a complimentary breach assessment from Cyngular:
- Safe and Non-disruptive: Conducted with read-only access to ensure no operational disruption.
- Easy Setup: Integrates seamlessly with your existing SIEM systems.
- Deep Insights: Empowers your cybersecurity strategy with advanced threat hunting and proactive investigation capabilities.
Request your free Proof-of-Value today and lead the way in cybersecurity innovation with Cyngular.
