CVE-2023-6200

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ImportantImportant ImpactWhat does this mean?
DescriptionStatementMitigationAdditional informationCVSS Score DetailsWeakness (CWE)AcknowledgementsFAQ

Description

A race condition was found in the Linux Kernel. Under certain conditions, an unauthenticated attacker from an adjacent network could send an ICMPv6 router advertisement packet, causing arbitrary code execution.

A race condition was found in the Linux Kernel. Under certain conditions, an unauthenticated attacker from an adjacent network could send an ICMPv6 router advertisement packet, causing arbitrary code execution.

Statement

To trigger this issue, the attacker must be on the local network, IPV6, and the parameter net.ipv6.conf must be enabled.[NIC].accept_ra enabled. By default, net.ipv6.conf.[NIC].accept_ra is disabled for Red Hat Enterprise Linux. In the default configuration, only local attacks are possible. The bug was introduced upstream by commit 3dec89b14d37 ("net/ipv6: Remove expired routes with a separated list of routes.").

To trigger this issue, the attacker must be on the local network, IPV6, and the parameter net.ipv6.conf must be enabled.[NIC].accept_ra enabled. By default, net.ipv6.conf.[NIC].accept_ra is disabled for Red Hat Enterprise Linux. In the default configuration, only local attacks are possible. The bug was introduced upstream by commit 3dec89b14d37 ("net/ipv6: Remove expired routes with a separated list of routes.").

Mitigation

The remote attack is potentially possible in the local network only. It is not possible if param
net.ipv6.conf.[NIC].accept_ra
disabled. Check this param value with the command
cat /proc/sys/net/ipv6/conf/default/accept_ra
or /proc/sys/net/ipv6/conf/eth0/accept_ra
(where eth0 is the name of the networking interface).
If you cannot run this or a similar command and parameter accept_ra is not available, then IPV6 is disabled.
If IPV6 is not being used, it is possible to disable it completely, and there is instruction on how to do this:
https://access.redhat.com/solutions/8709

Additional information

  • Bugzilla 2250377: kernel: ICMPv6 Router Advertisement packets, aka Linux TCP/IP Remote Code Execution Vulnerability
  • CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
  • FAQ: Frequently asked questions about CVE-2023-6200

Common Vulnerability Scoring System (CVSS) Score Details

Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).

The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 Score Breakdown
Red HatNVD

CVSS v3 Base Score

7.5

7.5

Attack Vector

Adjacent Network

Adjacent Network

Attack Complexity

High

High

Privileges Required

None

None

User Interaction

None

None

Scope

Unchanged

Unchanged

Confidentiality Impact

High

High

Integrity Impact

High

High

Availability Impact

High

High

CVSS v3 Vector

Red Hat: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

NVD: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Acknowledgements

Red Hat would like to thank Lucas Leong (Trend Micro Zero Day Initiative) for reporting this issue.

Frequently Asked Questions

Why is Red Hat's CVSS v3 score or Impact different from other vendors?

For open source software shipped by multiple vendors, the CVSS base scores may vary for each vendor's version depending on the version they ship, how they ship it, the platform, and even how the software is compiled. This makes scoring of vulnerabilities difficult for third-party vulnerability databases such as NVD that only provide a single CVSS base score for each vulnerability. Red Hat scores reflect how a vulnerability affects our products specifically.

For more information, see https://access.redhat.com/solutions/762393.

My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?

  • "Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.
  • The term "Affected" means that our Analysis team has determined that this product, such as Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to address this issue in the near future. This includes all minor releases of this product unless noted otherwise in the Statement text.

What can I do if my product is listed as "Will not fix"?

A "will not fix" status means that a fix for an affected product version is not planned or not possible due to complexity, which may create additional risk.

Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
  • Upgrade to a supported product version that includes a fix for this vulnerability (recommended).
  • Apply a mitigation (if one exists).
  • Open a support case to request a prioritization of releasing a fix for this vulnerability.

What can I do if my product is listed as "Fix deferred"?

A deferred status means that a fix for an affected product version is not guaranteed due to higher-priority development work.

Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
  • Apply a mitigation (if one exists).
  • Open a support case to request a prioritization of releasing a fix for this vulnerability.
  • Red Hat Engineering focuses on addressing high-priority issues based on their complexity or limited lifecycle support. Therefore, lower-priority issues will not receive immediate fixes.

What is a mitigation?

A mitigation is an action that can be taken to reduce the impact of a security vulnerability, without deploying any fixes.

I have a Red Hat product but it is not in the above list, is it affected?

The listed products were found to include one or more of the components that this vulnerability affects. These products underwent a thorough evaluation to determine their affectedness by this vulnerability. Note that layered products (such as container-based offerings) that consume affected components from any of the products listed in this table may be affected and are not represented.

Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?

In order to maintain code stability and compatibility, Red Hat usually does not rebase packages to entirely new versions. Instead, we backport fixes and new features to an older version of the package we distribute. This can result in some security scanners that only consider the package version to report the package as vulnerable. To avoid this, we suggest that you use an approved vulnerability scanner from our Red Hat Vulnerability Scanner Certification program.

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