On August 19, the Kubernetes Community disclosed that a security issue has been found in the net/http library of the Go language affecting all versions and all components of Kubernetes. This can further result in a DoS attack against any process with an HTTP or HTTPS listener.
The two high severity vulnerabilities, CVE-2019-9512 and CVE-2019-9514 have been assigned CVSS v3.0 base scores of 7.5 by the Kubernetes Product Security Committee. These vulnerabilities allow untrusted clients to allocate an unlimited amount of memory until the server crashes. The Kubernetes’ development team has released patched versions to address these security flaws to further block potential attackers from exploiting them.
CVE-2019-9512 Ping Flood
In CVE-2019-9512, the attacker sends continual pings to an HTTP/2 peer, causing the peer to build an internal queue of responses. Depending on how efficiently this data is queued, this can consume excess CPU, memory, or both, potentially leading to a denial of service.
CVE-2019-9514 Reset Flood
In CVE-2019-9514, the attacker opens a number of streams and sends an invalid request over each stream that should solicit a stream of RST_STREAM frames from the peer. Depending on how the peer queues the RST_STREAM frames, this can consume excess memory, CPU, or both, potentially leading to a denial of service.
The Go team announced versions go1.12.8 and go1.11.13, following which the Kubernetes developer team has released patch versions of Kubernetes built using the new versions of Go.
- Kubernetes v1.15.3 – go1.12.9
- Kubernetes v1.14.6 – go1.12.9
- Kubernetes v1.13.10 – go1.11.13
On August 13, Netflix announced the discovery of multiple vulnerabilities that can affect server implementations of the HTTP/2 protocol. The popular video streaming website issued eight CVEs in their security advisory and two of these also impact Go and all Kubernetes components designed to serve HTTP/2 traffic (including /healthz).
The Azure Kubernetes Service community has recommended customers to upgrade to a patched release soon. “Customers running minor versions lower than the above (1.10, 1.11, 1.12) are also impacted and should also upgrade to one of the releases above to mitigate these CVEs”, the team suggests.
To know more about this news in detail, read AKS Guidance and updates on GitHub.