Amazon Linux 2 : docker (ALASDOCKER-2024-040)

critical Nessus Plugin ID 204943

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Synopsis

The remote Amazon Linux 2 host is missing a security update.

Description

The version of docker installed on the remote host is prior to 25.0.6-1. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2DOCKER-2024-040 advisory.

2024-08-27: CVE-2024-29018 was added to this advisory.

2024-08-27: CVE-2024-24786 was added to this advisory.

The protojson.Unmarshal function can enter an infinite loop when unmarshaling certain forms of invalid JSON. This condition can occur when unmarshaling into a message which contains a google.protobuf.Any value, or when the UnmarshalOptions.DiscardUnknown option is set. (CVE-2024-24786)

Moby is an open source container framework that is a key component of Docker Engine, Docker Desktop, and other distributions of container tooling or runtimes. Moby's networking implementation allows for many networks, each with their own IP address range and gateway, to be defined. This feature is frequently referred to as custom networks, as each network can have a different driver, set of parameters and thus behaviors. When creating a network, the `--internal` flag is used to designate a network as _internal_.
The `internal` attribute in a docker-compose.yml file may also be used to mark a network _internal_, and other API clients may specify the `internal` parameter as well.

When containers with networking are created, they are assigned unique network interfaces and IP addresses.
The host serves as a router for non-internal networks, with a gateway IP that provides SNAT/DNAT to/from container IPs.

Containers on an internal network may communicate between each other, but are precluded from communicating with any networks the host has access to (LAN or WAN) as no default route is configured, and firewall rules are set up to drop all outgoing traffic. Communication with the gateway IP address (and thus appropriately configured host services) is possible, and the host may communicate with any container IP directly.

In addition to configuring the Linux kernel's various networking features to enable container networking, `dockerd` directly provides some services to container networks. Principal among these is serving as a resolver, enabling service discovery, and resolution of names from an upstream resolver.

When a DNS request for a name that does not correspond to a container is received, the request is forwarded to the configured upstream resolver. This request is made from the container's network namespace: the level of access and routing of traffic is the same as if the request was made by the container itself.

As a consequence of this design, containers solely attached to an internal network will be unable to resolve names using the upstream resolver, as the container itself is unable to communicate with that nameserver. Only the names of containers also attached to the internal network are able to be resolved.

Many systems run a local forwarding DNS resolver. As the host and any containers have separate loopback devices, a consequence of the design described above is that containers are unable to resolve names from the host's configured resolver, as they cannot reach these addresses on the host loopback device. To bridge this gap, and to allow containers to properly resolve names even when a local forwarding resolver is used on a loopback address, `dockerd` detects this scenario and instead forward DNS requests from the host namework namespace. The loopback resolver then forwards the requests to its configured upstream resolvers, as expected.

Because `dockerd` forwards DNS requests to the host loopback device, bypassing the container network namespace's normal routing semantics entirely, internal networks can unexpectedly forward DNS requests to an external nameserver. By registering a domain for which they control the authoritative nameservers, an attacker could arrange for a compromised container to exfiltrate data by encoding it in DNS queries that will eventually be answered by their nameservers.

Docker Desktop is not affected, as Docker Desktop always runs an internal resolver on a RFC 1918 address.

Moby releases 26.0.0, 25.0.4, and 23.0.11 are patched to prevent forwarding any DNS requests from internal networks. As a workaround, run containers intended to be solely attached to internal networks with a custom upstream address, which will force all upstream DNS queries to be resolved from the container's network namespace. (CVE-2024-29018)

AWS is aware of CVE-2024-41110, an issue affecting the Moby open source project, packaged in Amazon Linux as docker. Docker is a component of several open source container management systems.

This issue does not affect the default configuration of docker. If an authorization plugin is enabled, a specially-crafted API request to the docker daemon will be forwarded to the authorization plugin in a way that could lead to unintended actions, such as privilege escalation. Enabling an authorization plugin is an atypical configuration. The affected API endpoint is not exposed to the network in either the default, typical, or recommended configurations. The default EKS and ECS configurations do not expose the API endpoint to the network. Enabling a Docker authorization plugin is not supported when using ECS. Finally, docker is not installed on EKS AMIs newer than 1.24. Although Docker is installed in EKS 1.24 and earlier, EKS does not support authorization plugins.

Updated docker packages addressing the issue are available for Amazon Linux 2 (docker-20.10.25-1.amzn2.0.5 and docker-25.0.6-1.amzn2.0.1) and for Amazon Linux 2023 (docker-25.0.6-1amzn2023.0.1). AWS recommends that customers using docker upgrade to these or later versions. (CVE-2024-41110)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Run 'yum update docker' to update your system.

Plugin Details

Severity: Critical

ID: 204943

File Name: al2_ALASDOCKER-2024-040.nasl

Version: 1.5

Type: local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 8/1/2024

Updated: 8/29/2024

Supported Sensors: Agentless Assessment, Continuous Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Critical

Score: 9.2

CVSS v2

Risk Factor: High

Base Score: 9

Temporal Score: 7

Vector: CVSS2#AV:N/AC:L/Au:S/C:C/I:C/A:C

CVSS Score Source: CVE-2024-41110

CVSS v3

Risk Factor: Critical

Base Score: 9.9

Temporal Score: 8.9

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:docker, cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:docker-debuginfo

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 7/29/2024

Vulnerability Publication Date: 7/23/2024

Reference Information

CVE: CVE-2024-24786, CVE-2024-29018, CVE-2024-41110

IAVA: 2024-A-0438

Detections

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