CVE-2021-22884

Public on

Last Modified: UTC

ModerateModerate ImpactWhat does this mean?
DescriptionStatementMitigationAdditional informationAffected PackagesCVSS Score DetailsWeakness (CWE)FAQ

Description

A flaw was found in nodejs. A denial of service is possible when the whitelist includes “localhost6”. When “localhost6” is not present in /etc/hosts, it is just an ordinary domain that is resolved via DNS over the network. If the attacker controls the victim's DNS server or can spoof its responses, the DNS rebinding protection can be bypassed by using the “localhost6” domain. As long as the attacker uses the “localhost6” domain, they can still apply the attack described in CVE-2018-7160.

A flaw was found in nodejs. A denial of service is possible when the whitelist includes “localhost6”. When “localhost6” is not present in /etc/hosts, it is just an ordinary domain that is resolved via DNS over the network. If the attacker controls the victim's DNS server or can spoof its responses, the DNS rebinding protection can be bypassed by using the “localhost6” domain. As long as the attacker uses the “localhost6” domain, they can still apply the attack described in CVE-2018-7160.

Statement

Red Hat Enterprise Linux ships with `localhost` and `localhost6` defined in `/etc/hosts`, and thus in general, would not be affected by this flaw, with some specific exceptions, such as : - `/etc/hosts` is disabled or has its default content (including `localhost6`) removed - the inspector is accessed using SSH tunneling from a remote computer that does not have `localhost6` statically defined Red Hat Quay from version 3.4 consumes the nodejs from RHEL, so security tracking is provided by the container health index on the customer portal [1]. Additionally there is no impact from this issue on Quay 3.3 and 3.2 because they don't use the debug option (--inspect) and nodejs is only used at build time [2]. [1] https://catalog.redhat.com/software/containers/quay/quay-rhel8/600e03aadd19c7786c43ae49?container-tabs=security [2] https://issues.redhat.com/browse/PROJQUAY-1409

Red Hat Enterprise Linux ships with localhost and localhost6 defined in /etc/hosts, and thus in general, would not be affected by this flaw, with some specific exceptions, such as :

  • /etc/hosts is disabled or has its default content (including localhost6) removed
  • the inspector is accessed using SSH tunneling from a remote computer that does not have localhost6 statically defined

Red Hat Quay from version 3.4 consumes the nodejs from RHEL, so security tracking is provided by the container health index on the customer portal [1]. Additionally there is no impact from this issue on Quay 3.3 and 3.2 because they don't use the debug option (--inspect) and nodejs is only used at build time [2]. [1] https://catalog.redhat.com/software/containers/quay/quay-rhel8/600e03aadd19c7786c43ae49?container-tabs=security [2] https://issues.redhat.com/browse/PROJQUAY-1409

Mitigation

Ensure that 'localhost6' is part of /etc/hosts.
e.g.: 

$ grep localhost6 /etc/hosts
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

Additional information

  • Bugzilla 1932024: nodejs: DNS rebinding in --inspect
  • CWE-20: Improper Input Validation
  • FAQ: Frequently asked questions about CVE-2021-22884

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).

CVSS v3 Score Breakdown
Red HatNVD

CVSS v3 Base Score

7.5

7.5

Attack Vector

Network

Network

Attack Complexity

High

High

Privileges Required

None

None

User Interaction

Required

Required

Scope

Unchanged

Unchanged

Confidentiality Impact

High

High

Integrity Impact

High

High

Availability Impact

High

High

CVSS v3 Vector

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

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

Red Hat CVSS v3 Score Explanation

Red Hat considers the Attack Complexity to be High, as the attacker needs to control the responses to the victim's DNS requests in order to momentarily redirect the "localhost6" request to an attacker owned IP address.

Red Hat considers the Attack Complexity to be High, as the attacker needs to control the responses to the victim's DNS requests in order to momentarily redirect the "localhost6" request to an attacker owned IP address.

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.
  • "Affected" means that our Analysis Team has determined that this product is affected by this vulnerability and might release a fix to address this in the near future.

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.

Want to get errata notifications? Sign up here.