Bug 1214109 (CVE-2023-28842) - VUL-0: CVE-2023-28842: docker,golang-github-docker-libnetwork: Encrypted overlay network with a single endpoint is unauthenticated
Summary: VUL-0: CVE-2023-28842: docker,golang-github-docker-libnetwork: Encrypted over...
Status: RESOLVED FIXED
Alias: CVE-2023-28842
Product: SUSE Security Incidents
Classification: Novell Products
Component: Incidents (show other bugs)
Version: unspecified
Hardware: Other Other
: P2 - High : Normal
Target Milestone: ---
Assignee: Containers Team
QA Contact: Security Team bot
URL: https://smash.suse.de/issue/362376/
Whiteboard: CVSSv3.1:SUSE:CVE-2023-28842:6.8:(AV:...
Keywords:
Depends on:
Blocks:
 
Reported: 2023-08-09 08:51 UTC by Gabriele Sonnu
Modified: 2023-10-11 11:20 UTC (History)
5 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 08:51:52 UTC
CVE-2023-28842

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.

The overlay driver dynamically and lazily defines the kernel configuration for the VXLAN network on each node as containers are attached and detached. Routes and encryption parameters are only defined for destination nodes that participate in the network. The iptables rules that prevent encrypted overlay networks from accepting unencrypted packets are not created until a peer is available with which to communicate.

Impact

Encrypted overlay networks 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 implications of this can be quite dire, and GHSA-vwm3-crmr-xfxw should be referenced for a deeper exploration.

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

 - In multi-node clusters, deploy a global ‘pause’ container for each encrypted
   overlay network, on every node. For example, use the registry.k8s.io/pause
   image and a --mode global service.
 - For a single-node cluster, do not use overlay networks of any sort. Bridge 
   networks provide the same connectivity on a single node and have no 
   multi-node features.
 - The Swarm ingress feature is implemented using an overlay network, but can 
   be disabled by publishing ports in host mode instead of ingress mode
   (allowing the use of an external load balancer), and removing the ingress
   network.
 - If encrypted overlay networks are in exclusive use, block UDP port 4789 from
   traffic that has not been validated by IPSec. For example, iptables -A INPUT
   -m udp —-dport 4789 -m policy --dir in --pol none -j DROP.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2023-28842
https://bugzilla.redhat.com/show_bug.cgi?id=2184688
https://www.cve.org/CVERecord?id=CVE-2023-28842
https://github.com/moby/libnetwork/security/advisories/GHSA-gvm4-2qqg-m333
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 08:57:15 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-6wrf-mxfj-pf5p

Upstream patch:

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

(same fix as bug 1214107 and 1214108)
Comment 4 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 5 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.