A vulnerability was found in CNCF CNI 0.7.4. It has been declared as critical. Affected by this vulnerability is an unknown code block of the component Network Firewall. The manipulation with an unknown input leads to a 7pk security vulnerability. The CWE definition for the vulnerability is CWE-254. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Cloud Native Computing Foundation (CNCF) CNI (Container Networking Interface) 0.7.4 has a network firewall misconfiguration which affects Kubernetes. The CNI 'portmap' plugin, used to setup HostPorts for CNI, inserts rules at the front of the iptables nat chains; which take precedence over the KUBE- SERVICES chain. Because of this, the HostPort/portmap rule could match incoming traffic even if there were better fitting, more specific service definition rules like NodePorts later in the chain. The issue is fixed in CNI 0.7.5 and Kubernetes 1.11.9, 1.12.7, 1.13.5, and 1.14.0.

The bug was discovered 03/28/2019. The weakness was shared 04/02/2019 (GitHub Repository). It is possible to read the advisory at github.com. This vulnerability is known as CVE-2019-9946 since 03/23/2019. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1211 according to MITRE ATT&CK.

The vulnerability was handled as a non-public zero-day exploit for at least 5 days. During that time the estimated underground price was around $0-$5k.

Upgrading to version 0.7.5 eliminates this vulnerability.

Affected

• Kubernetes up to 1.11.8/1.12.6/1.13.4

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Vendor

• CNCF

Name

• CNI

Version

• 0.7.4

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