CVE-2022-24877 in Flux
Summary
by MITRE • 05/06/2022
Flux is an open and extensible continuous delivery solution for Kubernetes. Path Traversal in the kustomize-controller via a malicious `kustomization.yaml` allows an attacker to expose sensitive data from the controller’s pod filesystem and possibly privilege escalation in multi-tenancy deployments. Workarounds include automated tooling in the user's CI/CD pipeline to validate `kustomization.yaml` files conform with specific policies. This vulnerability is fixed in kustomize-controller v0.24.0 and included in flux2 v0.29.0.
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Analysis
by VulDB Data Team • 05/08/2022
The vulnerability CVE-2022-24877 represents a critical path traversal flaw in the kustomize-controller component of the Flux continuous delivery solution for Kubernetes environments. This issue specifically affects how the controller processes kustomization.yaml files, creating a potential attack vector that could allow adversaries to access sensitive data from the controller's pod filesystem. The vulnerability exists within the kustomize-controller's handling of user-supplied configuration files, where improper input validation enables attackers to manipulate file paths and access unauthorized system resources.
The technical implementation of this vulnerability stems from insufficient sanitization of path references within kustomization.yaml files. When the kustomize-controller processes these configuration files, it fails to properly validate or normalize file paths that may contain traversal sequences such as ../ or ..\, allowing attackers to navigate outside of intended directories and access arbitrary files within the controller pod's filesystem. This flaw operates at the application level within the Kubernetes environment, specifically targeting the controller's file system access mechanisms during kustomization operations. The vulnerability is classified under CWE-22 Path Traversal, which is a well-documented weakness in software applications that handle file system operations without proper input validation and sanitization.
The operational impact of this vulnerability extends beyond simple data exposure, potentially enabling privilege escalation in multi-tenancy deployments where multiple users or teams share the same Kubernetes cluster. In such environments, an attacker could leverage this vulnerability to access configuration files, secrets, or other sensitive artifacts belonging to other tenants or system components. The risk is particularly elevated in continuous integration and continuous deployment pipelines where kustomization.yaml files are automatically processed without additional validation layers. The vulnerability affects the integrity and confidentiality of the entire Flux deployment ecosystem, potentially compromising the security posture of organizations relying on automated Kubernetes deployment workflows.
Mitigation strategies for CVE-2022-24877 involve both immediate remediation and long-term architectural improvements. Organizations should upgrade to kustomize-controller version 0.24.0 or later, which includes patches addressing the path traversal vulnerability, and ensure that flux2 installations are updated to version 0.29.0 or higher. Additionally, implementing automated validation mechanisms within CI/CD pipelines can serve as a critical defense-in-depth measure, validating kustomization.yaml files against established policies before processing. These validation tools should enforce strict path validation rules and prevent the inclusion of potentially malicious traversal sequences. Security teams should also consider implementing network segmentation, pod security policies, and least privilege access controls to limit the potential impact should the vulnerability be exploited. The ATT&CK framework categorizes this vulnerability under T1059 Command and Scripting Interpreter and T1566 Phishing, as attackers may use this weakness to escalate privileges or extract sensitive information from compromised systems.