CVE-2022-2837 in coreDNS
Summary
by MITRE • 03/03/2023
A flaw was found in coreDNS. This flaw allows a malicious user to redirect traffic intended for external top-level domains (TLD) to a pod they control by creating projects and namespaces that match the TLD.
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Analysis
by VulDB Data Team • 07/06/2025
The vulnerability identified as CVE-2022-2837 resides within the coreDNS implementation, representing a significant security flaw that undermines the integrity of DNS resolution mechanisms in containerized environments. This weakness specifically affects systems where coreDNS serves as the primary DNS server for Kubernetes clusters, creating a potential attack vector that could compromise network traffic routing and data integrity. The flaw manifests when malicious actors exploit the DNS resolution process to manipulate traffic intended for external top-level domains by leveraging the naming conventions used within Kubernetes clusters.
The technical root cause of this vulnerability stems from coreDNS's handling of domain name resolution when namespaces and projects within the Kubernetes cluster match the structure of external top-level domains. When a malicious user creates a namespace or project that corresponds to a valid TLD such as .com, .org, or .net, the DNS resolution process can be manipulated to redirect traffic intended for external domains to pods controlled by the attacker. This occurs because coreDNS does not properly validate or sanitize the namespace names against external domain structures, allowing for unintended resolution conflicts. The flaw operates at the intersection of DNS resolution logic and Kubernetes resource naming conventions, creating a scenario where internal cluster resources can inadvertently override external DNS records.
The operational impact of CVE-2022-2837 extends beyond simple traffic redirection, potentially enabling sophisticated attack scenarios that could compromise sensitive data flows and system integrity. Attackers could leverage this vulnerability to perform man-in-the-middle attacks, redirect users to malicious websites, or intercept communications intended for legitimate external services. The vulnerability particularly affects environments where Kubernetes clusters interact with external services, making it a critical concern for organizations relying on containerized infrastructure for production workloads. This flaw represents a significant risk to network security posture and could facilitate broader attacks that exploit the compromised DNS resolution to gain unauthorized access to downstream systems.
Mitigation strategies for CVE-2022-2837 should focus on implementing proper namespace naming conventions that avoid conflicts with external TLDs and establishing robust DNS validation mechanisms within the coreDNS configuration. Organizations should enforce strict naming policies that prevent the creation of namespaces matching common TLD structures, while also considering the implementation of DNS security extensions and proper access controls. The vulnerability aligns with CWE-20 Improper Input Validation, as it stems from insufficient validation of namespace names against external domain structures, and may be exploited through techniques consistent with ATT&CK tactics such as DNS tunneling and credential access. Regular monitoring of DNS resolution patterns and implementing automated checks for namespace naming conflicts can help detect and prevent exploitation attempts. Additionally, updating coreDNS to versions that address this specific vulnerability and conducting comprehensive security audits of cluster configurations are essential steps in maintaining defensive posture against this class of attack.