RHSA-2019:3941 - Security Advisory

Topic

Red Hat OpenShift Container Platform release 4.1.24 is now available with updates to packages and images that fix several bugs and add enhancements.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

Red Hat OpenShift Container Platform is Red Hat's cloud computing Kubernetes application platform solution designed for on-premise or private cloud deployments.

This is a text-only advisory for the machine-os-content container image, which includes RPM packages for Red Hat Enterprise Linux CoreOS.

Security Fix(es):

• A flaw was found in the way Intel CPUs handle inconsistency between, virtual to physical memory address translations in CPU's local cache and system software's Paging structure entries. A privileged guest user may use this flaw to induce a hardware Machine Check Error on the host processor, resulting in a severe DoS scenario by halting the processor.

System software like OS OR Virtual Machine Monitor (VMM) use virtual memory system for storing program instructions and data in memory. Virtual Memory system uses Paging structures like Page Tables and Page Directories to manage system memory. The processor's Memory Management Unit (MMU) uses Paging structure entries to translate program's virtual memory addresses to physical memory addresses. The processor stores these address translations into its local cache buffer called - Translation Lookaside Buffer (TLB). TLB has two parts, one for instructions and other for data addresses.

System software can modify its Paging structure entries to change address mappings OR certain attributes like page size etc. Upon such Paging structure alterations in memory, system software must invalidate the corresponding address translations in the processor's TLB cache. But before this TLB invalidation takes place, a privileged guest user may trigger an instruction fetch operation, which could use an already cached, but now invalid, virtual to physical address translation from Instruction TLB (ITLB). Thus accessing an invalid physical memory address and resulting in halting the processor due to the Machine Check Error (MCE) on Page Size Change. (CVE-2018-12207)

• A flaw was found in the way sudo implemented running commands with an arbitrary user ID. If a sudoers entry is written to allow users to run a command as any user except root, this flaw can be used by an attacker to bypass that restriction. (CVE-2019-14287)
• An improper authorization flaw was discovered in systemd-resolved in the way it configures the exposed DBus interface org.freedesktop.resolve1. An unprivileged local user could call all DBus methods, even when marked as privileged operations. An attacker could abuse this flaw by changing the DNS, Search Domain, LLMNR, DNSSEC, and other network link settings without any authorization, giving them control of the network names resolution process and causing the system to communicate with wrong or malicious servers. (CVE-2019-15718)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Solution

For OpenShift Container Platform 4.1 see the following documentation, which
will be updated shortly for release 4.1.24, for important instructions on
how to upgrade your cluster and fully apply this asynchronous errata
update:

https://docs.openshift.com/container-platform/4.1/release_notes/ocp-4-1-release-notes.html

Affected Products

• Red Hat OpenShift Container Platform 4.1 for RHEL 7 x86_64

Fixes

• BZ - 1646768 - CVE-2018-12207 hw: Machine Check Error on Page Size Change (IFU)
• BZ - 1746057 - CVE-2019-15718 systemd: systemd-resolved allows unprivileged users to configure DNS
• BZ - 1760531 - CVE-2019-14287 sudo: Privilege escalation via 'Runas' specification with 'ALL' keyword

CVEs

• CVE-2018-12207
• CVE-2019-14287
• CVE-2019-15718

References

• https://access.redhat.com/security/updates/classification/#important
• https://access.redhat.com/security/vulnerabilities/ifu-page-mce