Bug 1214107 (CVE-2023-28840) - VUL-0: CVE-2023-28840: golang-github-docker-libnetwork,docker: Encrypted overlay network may be unauthenticated
Summary: VUL-0: CVE-2023-28840: golang-github-docker-libnetwork,docker: Encrypted over...
Status: RESOLVED FIXED
Alias: CVE-2023-28840
Product: SUSE Security Incidents
Classification: Novell Products
Component: Incidents (show other bugs)
Version: unspecified
Hardware: Other Other
: P2 - High : Major
Target Milestone: ---
Assignee: Containers Team
QA Contact: Security Team bot
URL: https://smash.suse.de/issue/362374/
Whiteboard: CVSSv3.1:SUSE:CVE-2023-28840:7.5:(AV:...
Keywords:
Depends on:
Blocks:
 
Reported: 2023-08-09 08:47 UTC by Gabriele Sonnu
Modified: 2024-05-23 08:34 UTC (History)
9 users (show)

See Also:
Found By: Security Response Team
Services Priority:
Business Priority:
Blocker: ---
Marketing QA Status: ---
IT Deployment: ---


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Description Gabriele Sonnu 2023-08-09 08:47:41 UTC
CVE-2023-28840

Moby is an open source container framework developed by Docker Inc. that is distributed as Docker, Mirantis Container Runtime, and various other downstream projects/products. The Moby daemon component (dockerd), which is developed as moby/moby is commonly referred to as Docker.

Swarm Mode, which is compiled in and delivered by default in dockerd and is thus present in most major Moby downstreams, is a simple, built-in container orchestrator that is implemented through a combination of SwarmKit and supporting network code.

The overlay network driver is a core feature of Swarm Mode, providing isolated virtual LANs that allow communication between containers and services across the cluster. This driver is an implementation/user of VXLAN, which encapsulates link-layer (Ethernet) frames in UDP datagrams that tag the frame with a VXLAN Network ID (VNI) that identifies the originating overlay network. In addition, the overlay network driver supports an optional, off-by-default encrypted mode, which is especially useful when VXLAN packets traverses an untrusted network between nodes.

Encrypted overlay networks function by encapsulating the VXLAN datagrams through the use of the IPsec Encapsulating Security Payload protocol in Transport mode. By deploying IPSec encapsulation, encrypted overlay networks gain the additional properties of source authentication through cryptographic proof, data integrity through check-summing, and confidentiality through encryption.

When setting an endpoint up on an encrypted overlay network, Moby installs three iptables (Linux kernel firewall) rules that enforce both incoming and outgoing IPSec. These rules rely on the u32 iptables extension provided by the xt_u32 kernel module to directly filter on a VXLAN packet's VNI field, so that IPSec guarantees can be enforced on encrypted overlay networks without interfering with other overlay networks or other users of VXLAN.

Two iptables rules serve to filter incoming VXLAN datagrams with a VNI that corresponds to an encrypted network and discards unencrypted datagrams. The rules are appended to the end of the INPUT filter chain, following any rules that have been previously set by the system administrator. Administrator-set rules take precedence over the rules Moby sets to discard unencrypted VXLAN datagrams, which can potentially admit unencrypted datagrams that should have been discarded.

On Red Hat Enterprise Linux and derivatives such as CentOS and Rocky, the xt_u32 module has been:

 - moved to the kernel-modules-extra package and no longer installed by default
   in RHEL 8.3
 - officially deprecated in RHEL 8.6
 - removed completely in RHEL 9

These rules are not created when xt_u32 is unavailable, even though the container is still attached to the network.

Impact

Encrypted overlay networks on affected configurations silently accept cleartext VXLAN datagrams that are tagged with the VNI of an encrypted overlay network. As a result, it is possible to inject arbitrary Ethernet frames into the encrypted overlay network by encapsulating them in VXLAN datagrams.

The injection of arbitrary Ethernet frames can enable a Denial of Service attack. A sophisticated attacker may be able to establish a UDP or TCP connection by way of the container’s outbound gateway that would otherwise be blocked by a stateful firewall, or carry out other escalations beyond simple injection by smuggling packets into the overlay network.

Patches

Patches are available in Moby releases 23.0.3, and 20.10.24. As Mirantis Container Runtime's 20.10 releases are numbered differently, users of that platform should update to 20.10.16.

Workarounds

 - Close the VXLAN port (by default, UDP port 4789) to incoming traffic at the
   Internet boundary (see GHSA-vwm3-crmr-xfxw) to prevent all VXLAN packet
   injection.
 - Ensure that the xt_u32 kernel module is available on all nodes of the Swarm 
   cluster.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2023-28840
https://bugzilla.redhat.com/show_bug.cgi?id=2184683
https://www.cve.org/CVERecord?id=CVE-2023-28840
https://github.com/moby/libnetwork/security/advisories/GHSA-gvm4-2qqg-m333
https://github.com/moby/moby/issues/43382
https://github.com/moby/moby/pull/45118
https://github.com/moby/moby/security/advisories/GHSA-232p-vwff-86mp
https://github.com/moby/moby/security/advisories/GHSA-33pg-m6jh-5237
https://github.com/moby/moby/security/advisories/GHSA-6wrf-mxfj-pf5p
https://github.com/moby/moby/security/advisories/GHSA-vwm3-crmr-xfxw
Comment 1 Gabriele Sonnu 2023-08-09 08:57:19 UTC
Tracking as affected:

 - SUSE:SLE-12:Update/docker
 - SUSE:SLE-12:Update/golang-github-docker-libnetwork
 - SUSE:SLE-15:Update/golang-github-docker-libnetwork

Upstream security advisory:

https://github.com/moby/moby/security/advisories/GHSA-232p-vwff-86mp

Upstream patch:

https://github.com/moby/libnetwork/commit/0d7f33e190f5c52414e18d7d76310554b704ba9c

(same fix as bug 1214108 and 1214109)
Comment 11 Maintenance Automation 2023-08-14 12:30:04 UTC
SUSE-SU-2023:3307-1: An update that solves three vulnerabilities can now be installed.

Category: security (important)
Bug References: 1214107, 1214108, 1214109
CVE References: CVE-2023-28840, CVE-2023-28841, CVE-2023-28842
Sources used:
Containers Module 12 (src): docker-20.10.25_ce-98.93.1

NOTE: This line indicates an update has been released for the listed product(s). At times this might be only a partial fix. If you have questions please reach out to maintenance coordination.
Comment 12 Joyeta Modak 2023-08-18 09:01:42 UTC
I am working on bsc1214185, and the customer wanted fix for CVE-2023-28840 on SLES15 SP2 LTSS and SLES15 SP3 LTSS.  Could it be confirmed if the fix would be released in the next MU.
Comment 13 Maintenance Automation 2023-09-05 16:30:18 UTC
SUSE-SU-2023:3536-1: An update that solves three vulnerabilities and has five security fixes can now be installed.

Category: security (moderate)
Bug References: 1210797, 1212368, 1213120, 1213229, 1213500, 1214107, 1214108, 1214109
CVE References: CVE-2023-28840, CVE-2023-28841, CVE-2023-28842
Sources used:
openSUSE Leap 15.4 (src): docker-24.0.5_ce-150000.185.1
openSUSE Leap 15.5 (src): docker-24.0.5_ce-150000.185.1
SUSE Linux Enterprise Micro for Rancher 5.3 (src): docker-24.0.5_ce-150000.185.1
SUSE Linux Enterprise Micro 5.3 (src): docker-24.0.5_ce-150000.185.1
SUSE Linux Enterprise Micro for Rancher 5.4 (src): docker-24.0.5_ce-150000.185.1
SUSE Linux Enterprise Micro 5.4 (src): docker-24.0.5_ce-150000.185.1
Containers Module 15-SP4 (src): docker-24.0.5_ce-150000.185.1
Containers Module 15-SP5 (src): docker-24.0.5_ce-150000.185.1
SUSE Linux Enterprise High Performance Computing 15 SP1 LTSS 15-SP1 (src): docker-24.0.5_ce-150000.185.1
SUSE Linux Enterprise High Performance Computing 15 SP2 LTSS 15-SP2 (src): docker-24.0.5_ce-150000.185.1
SUSE Linux Enterprise High Performance Computing ESPOS 15 SP3 (src): docker-24.0.5_ce-150000.185.1
SUSE Linux Enterprise High Performance Computing LTSS 15 SP3 (src): docker-24.0.5_ce-150000.185.1
SUSE Linux Enterprise Server 15 SP1 LTSS 15-SP1 (src): docker-24.0.5_ce-150000.185.1
SUSE Linux Enterprise Server 15 SP2 LTSS 15-SP2 (src): docker-24.0.5_ce-150000.185.1
SUSE Linux Enterprise Server 15 SP3 LTSS 15-SP3 (src): docker-24.0.5_ce-150000.185.1
SUSE Linux Enterprise Server for SAP Applications 15 SP1 (src): docker-24.0.5_ce-150000.185.1
SUSE Linux Enterprise Server for SAP Applications 15 SP2 (src): docker-24.0.5_ce-150000.185.1
SUSE Linux Enterprise Server for SAP Applications 15 SP3 (src): docker-24.0.5_ce-150000.185.1
SUSE Enterprise Storage 7.1 (src): docker-24.0.5_ce-150000.185.1
SUSE CaaS Platform 4.0 (src): docker-24.0.5_ce-150000.185.1
SUSE Linux Enterprise Micro 5.1 (src): docker-24.0.5_ce-150000.185.1
SUSE Linux Enterprise Micro 5.2 (src): docker-24.0.5_ce-150000.185.1
SUSE Linux Enterprise Micro for Rancher 5.2 (src): docker-24.0.5_ce-150000.185.1

NOTE: This line indicates an update has been released for the listed product(s). At times this might be only a partial fix. If you have questions please reach out to maintenance coordination.
Comment 15 Robert Frohl 2024-05-23 08:34:18 UTC
done, closing