CVE-2021-3495 in kiali-operator
Summary
by MITRE • 06/02/2021
An incorrect access control flaw was found in the kiali-operator in versions before 1.33.0 and before 1.24.7. This flaw allows an attacker with a basic level of access to the cluster (to deploy a kiali operand) to use this vulnerability and deploy a given image to anywhere in the cluster, potentially gaining access to privileged service account tokens. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
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Analysis
by VulDB Data Team • 06/05/2021
The vulnerability identified as CVE-2021-3495 represents a critical access control flaw within the kiali-operator component of the Istio service mesh ecosystem. This issue affects versions prior to 1.33.0 and 1.24.7, creating a significant security gap that allows attackers with minimal privileges to escalate their access within the cluster environment. The kiali-operator serves as a crucial management component responsible for deploying and configuring kiali monitoring services, making it an attractive target for malicious actors seeking to expand their influence within the cluster infrastructure.
The technical flaw stems from improper validation of image deployment requests within the operator's privilege management system. Specifically, the vulnerability allows an attacker who has already gained the ability to deploy kiali operands to manipulate the deployment process and inject arbitrary container images throughout the cluster. This misconfiguration bypasses normal access controls that should restrict where images can be deployed, effectively granting the attacker the ability to execute code in privileged contexts. The flaw operates at the operator level where Kubernetes controllers typically enforce strict access policies, but the missing validation creates an exploitable path for privilege escalation.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it can lead to comprehensive compromise of cluster resources and data integrity. Attackers can leverage this vulnerability to deploy malicious containers that may access privileged service account tokens, potentially gaining access to sensitive cluster resources, including secrets, configuration data, and other critical infrastructure components. The threat landscape encompasses data confidentiality breaches where sensitive information can be exfiltrated, data integrity violations where system configurations can be altered, and system availability risks where cluster operations can be disrupted through malicious resource consumption or service disruption.
The vulnerability aligns with CWE-284, which addresses improper access control issues in software systems, and maps to ATT&CK technique T1078 for valid accounts and T1566 for spearphishing with a specific focus on privilege escalation through operator manipulation. Organizations running affected versions of kiali-operator face significant risk of lateral movement within their Kubernetes environments, as the compromised operator can serve as a foothold for broader cluster infiltration. The attack vector requires only basic cluster deployment permissions, making it particularly dangerous in environments where least privilege principles are not strictly enforced.
Mitigation strategies should focus on immediate version upgrades to 1.33.0 or 1.24.7, which contain the necessary access control fixes. Additionally, implementing strict network policies, monitoring for unauthorized image deployments, and enforcing pod security policies can help reduce the impact of potential exploitation. Organizations should also conduct comprehensive audits of their kiali-operator configurations and implement continuous monitoring for suspicious deployment activities. The fix addresses the core access control issue by implementing proper validation of deployment requests and ensuring that all image deployments adhere to established security policies, preventing unauthorized privilege escalation through the operator component.