CVE-2023-34091

Kyverno versions v1.9.0 through v1.12.7 contain a policy exception handling flaw. When an enforce-mode policy is combined with two PolicyExceptions, the less restrictive exception takes precedence, allowing an attacker to bypass the policy by crafting a resource name matching the second exception's pattern (e.g., '*ingress*'). This can be used to circumvent policies such as one blocking hostPath volumes. Fixed in v1.13.0.

Kyverno, a policy engine for cloud native platform engineering teams, from 1.18.0 until 1.18.2, the NamespacedMutatingPolicy CEL compiler exposes the generator library to matchConditions, allowing a namespace-scoped policy to invoke generator.apply(namespace, resources) with an arbitrary target namespace. The validation in pkg/cel/policies/mpol/validate.go checks that the policy compiles but does not enforce namespace scope, and GenerateResources in pkg/cel/libs/context.go does not reject the cross-namespace target. A user who can create NamespacedMutatingPolicy objects in one namespace can cause the admission controller, operating with cluster-wide privileges, to create ConfigMaps, NetworkPolicies, Secrets, RoleBindings, and other resources in another namespace, enabling unauthorized modification and potential privilege escalation. This issue is fixed in version 1.18.2.

Kyverno before 1.16.2 contains a server-side request forgery (SSRF) vulnerability in the APICall feature. The URL field in a Policy's ServiceCall configuration is not validated, so a user with namespace-level Policy creation permissions can direct Kyverno to make HTTP requests to arbitrary internal resources (e.g., cloud metadata endpoints such as 169.254.169.254 or other tenants' resources). Because Kyverno executes these requests using its cluster-wide high-privilege ServiceAccount (a Confused Deputy problem), the responses—potentially including other tenants' secrets and cloud IAM credentials—are returned in the PolicyReport and can be read by the attacker, breaking multi-tenant isolation.

Kyverno before 1.18.0 contains a server-side request forgery vulnerability in apiCall.service.url that allows authenticated users to send arbitrary HTTP requests by injecting user-controlled input through variable substitution. Attackers can target internal services, cloud metadata endpoints, and loopback addresses, with response data reflected in admission error messages enabling non-blind data exfiltration.

Kyverno before 1.16.4 automatically attaches the admission controller's ServiceAccount token to outbound HTTP requests in apiCall service mode without explicit authorization headers. Attackers can exfiltrate the token by directing apiCall requests to external or attacker-controlled endpoints, gaining full control over Kyverno policies and cluster resources.

Kyverno before v1.13.4 is vulnerable to server-side request forgery (SSRF) via its Service Call functionality. An attacker with permission to create Kyverno (Cluster)Policies can specify an external URL in a policy's apiCall/service configuration; although Service Call is documented for in-cluster services, it also resolves external addresses, allowing requests to an attacker-controlled server. Because policy context data (including contents of Kubernetes resources such as secrets) is sent in these requests, an attacker can exfiltrate sensitive cluster data.

Kyverno versions 1.9.4 and earlier support insecure 3DES cipher suites (TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA and TLS_RSA_WITH_3DES_EDE_CBC_SHA) on their TLS endpoints. These 64-bit block ciphers are vulnerable to the Sweet32 attack (CVE-2016-2183), which, over very long-lived TLS connections carrying large volumes of traffic, could allow an attacker to recover small amounts of plaintext. The issue is fixed in Kyverno 1.9.5 and 1.10.0.

Kyverno is a policy engine designed for Kubernetes. Seccomp control in Kyverno can be circumvented, affecting users of the `validate.podSecurity` subrule in versions 1.9.2 and 1.9.3. This issue was patched in version 1.9.4.