IngressNightmare? How AccuKnox Virtual Patching Mitigates CVE-2025-1974

Kubernetes, the leading platform for container orchestration, frequently faces security challenges. One of the latest and most severe vulnerabilities, IngressNightmare (CVE-2025-1974), exposes a critical weakness in Kubernetes ingress controllers. This flaw allows attackers to insert arbitrary directives, such as ssl_engine—to load malicious code or execute system commands remotely. Rated CVSS 9.8, this vulnerability enables attackers to bypass Ingress creation permissions, making it possible for any entity with network access to the controller, including internal pods and externally exposed services, to exploit the flaw.

Why is it Dangerous?

• Cluster-Wide Exposure: The ingress controller often has read access to all secrets in a cluster, allowing attackers to steal credentials, move laterally, and compromise data.
• Ransomware Threat: Remote code execution (RCE) can be leveraged to deploy ransomware, encrypt data, or use the ingress pod as a pivot point to attack other services.
• Multi-tenancy risks: In shared environments, one compromised tenant could lead to a complete cluster takeover.

Affected Setups

• Kubernetes clusters using ingress-nginx as the Ingress controller, particularly versions before v1.12.1 or v1.11.5.
• Clusters where the Validating Admission Controller is accessible to internal pod traffic or the public internet.

The Problem with Traditional Patching

Security teams often rush to apply vendor patches, but this approach has significant drawbacks. Patching requires testing, scheduling, and sometimes downtime—an unacceptable risk for mission-critical environments. Attackers move quickly; by the time an official patch is released and deployed, exploits may already be in active use. 

Virtual patching offers an immediate, non-disruptive solution by enforcing security controls at runtime without modifying the underlying system. This proactive approach reduces the attack surface and mitigates vulnerabilities before official patches are available.

Virtual Patching with AccuKnox

Virtual patching is a security strategy that mitigates vulnerabilities dynamically by enforcing security policies without requiring changes to application code or system binaries. AccuKnox implements this through KubeArmor, leveraging eBPF-based runtime security to enforce real-time security policies and neutralize threats before they can be weaponized.

AccuKnox’s virtual patching approach mitigates IngressNightmare (CVE-2025-1974) by blocking unauthorized executions, such as an RCE, and preventing malicious privilege escalations. Even if an ingress controller remains vulnerable, AccuKnox ensures attackers cannot exploit it, strengthening Kubernetes security against both zero-day exploits and known CVEs.

Demonstrating the Threat

Step 1: Deploying the Vulnerable Ingress Controller

To replicate the attack scenario, we first install the ingress nginx controller

kubectl apply -f 
https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v1.11.3/deploy/static/provider/baremetal/deploy.yaml

Step 2: Forwarding Ports

We forward the ports of the ingress admission controller and the ingress controller for external access:

Step 3: Exploiting the Vulnerability

Next, we execute the attack by:
Running the Exploit. We use publicly available PoCs to exploit the vulnerability. Find the PoC script here.

How does AccuKnox Neutralize the Attack?

AccuKnox Runtime Security provides powerful, real-time protection against unauthorized or malicious activities by enforcing security policies directly in your environment. By integrating AccuKnox’s policies, you can proactively block exploitation attempts and secure the environment from unauthorized access.

Step 1: Ensure AccuKnox Runtime Security is Configured

Verify that AccuKnox Runtime Security is installed and configured on your Kubernetes cluster to enable security enforcement.

Step 2: Applying Security Policies

1. Annotating the Namespace for Default Posture

2. Navigate to Policies: In the AccuKnox dashboard, go to the Policies section under the Runtime Security tab. Upload the pre-configured virtual patching policy and activate it.

This policy defends against ingress nightmare CVEs by blocking any unauthorized attempts. With AccuKnox Runtime Security policies applied, effectively mitigating exploits through virtual patching and ensuring Ingress nginx remains secure.

Step 3: Mitigation and Solution

Once the policy is applied, we reattempt the attack. This time, the exploit fails, showing that AccuKnox successfully blocks the attack vector.

After the policy enforcement, an alert is triggered in the AccuKnox dashboard, notifying us of the blocked access attempt. The alert provides detailed information about the blocked activity, including the source of the request, the policy, the process, etc.

Exploit Remediation with AccuKnox – A Recap

1. With eBPF-based security mechanisms, KubeArmor actively monitors and restricts suspicious activity.
2. By applying security annotations, AccuKnox enforces a strong default security posture.
3. A pre-built policy specific to CVE-2025-1974 was applied, blocking the exploit attempt in real time.
4. The attack simulation, which was initially successful, failed immediately after the virtual patch was deployed, demonstrating its effectiveness.

Security threats evolve rapidly, and organizations can no longer afford to rely solely on traditional patching. Virtual patching provides a much-needed agile security layer, ensuring rapid response to emerging threats without disrupting operational continuity.

With AccuKnox, Kubernetes security is no longer reactive—it’s proactive, intelligent, and adaptive. As new vulnerabilities like IngressNightmare emerge, virtual patching will remain a crucial tool in the arsenal of cloud security teams, ensuring resilience in an ever-changing threat landscape.