RHBA-2021:0242 - Bug Fix Advisory

Topic

Updated Red Hat OpenStack Platform 13.0 (Queens) container images are now available.

Description

The Red Hat OpenStack Platform 13.0 (Queens) container images have been updated to address the following security advisory: RHSA-2021:0153 (see References)

Users of Red Hat OpenStack Platform 13.0 (Queens) container images are advised to upgrade to these updated images, which contain backported patches to correct these security issues, fix these bugs and add these enhancements. Users of these images are also encouraged to rebuild all container images that depend on these images.

You can find images updated by this advisory in Red Hat Container Catalog (see References).

Changes to the vulnerability component:

A flaw was found in dnsmasq. When getting a reply from a forwarded query, dnsmasq checks in the forward.c:reply_query() if the reply destination address/port is used by the pending forwarded queries. However, it does not use the address/port to retrieve the exact forwarded query, substantially reducing the number of attempts an attacker on the network would have to perform to forge a reply and get it accepted by dnsmasq. This issue contrasts with RFC5452, which specifies a query's attributes that all must be used to match a reply. This flaw allows an attacker to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25685 or CVE-2020-25686, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity. (BZ#1889686)

A flaw was found in dnsmasq. When getting a reply from a forwarded query, dnsmasq checks in forward.c:reply_query(), which is the forwarded query that matches the reply, by only using a weak hash of the query name. Due to the weak hash (CRC32 when dnsmasq is compiled without DNSSEC, SHA-1 when it is) this flaw allows an off-path attacker to find several different domains all having the same hash, substantially reducing the number of attempts they would have to perform to forge a reply and get it accepted by dnsmasq. This is in contrast with RFC5452, which specifies that the query name is one of the attributes of a query that must be used to match a reply. This flaw could be abused to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25684 the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity. (BZ#1889688)

A flaw was found in dnsmasq. When receiving a query, dnsmasq does not check for an existing pending request for the same name and forwards a new request. By default, a maximum of 150 pending queries can be sent to upstream servers, so there can be at most 150 queries for the same name. This flaw allows an off-path attacker on the network to substantially reduce the number of attempts that it would have to perform to forge a reply and have it accepted by dnsmasq. This issue is mentioned in the "Birthday Attacks" section of RFC5452. If chained with CVE-2020-25684, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity. (BZ#1890125)

Solution

The Red Hat OpenStack Platform 13.0 (Queens) container images provided by this update can be downloaded from the Red Hat Container Registry at registry.access.redhat.com. Installation instructions for your platform are available at Red Hat Container Catalog (see References).

Dockerfiles and scripts should be amended either to refer to this new image specifically, or to the latest image generally.

Affected Products

• Red Hat OpenStack for IBM Power 13 ppc64le
• Red Hat OpenStack 13 x86_64

Fixes

• BZ - 1889686 - CVE-2020-25684 dnsmasq: loose address/port check in reply_query() makes forging replies easier for an off-path attacker
• BZ - 1889688 - CVE-2020-25685 dnsmasq: loose query name check in reply_query() makes forging replies easier for an off-path attacker
• BZ - 1890125 - CVE-2020-25686 dnsmasq: multiple queries forwarded for the same name makes forging replies easier for an off-path attacker
• BZ - 1918414 - [OSP13] Respin containers for dnsmasq async

CVEs

• CVE-2020-25684
• CVE-2020-25685
• CVE-2020-25686

References

• https://access.redhat.com/errata/RHSA-2021:0153
• https://access.redhat.com/containers