CVE-2021-22884
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.
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/hostsis disabled or has its default content (includinglocalhost6) removed- the inspector is accessed using SSH tunneling from a remote computer that does not have
localhost6statically 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
Common Vulnerability Scoring System (CVSS) Score Details
Info alert: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 Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | 7.5 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | High | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | Required | Required | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | High | High | N/A |
| Integrity Impact | High | High | N/A |
| Availability Impact | High | High | N/A |
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.
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)
An attacker could provide unexpected values and cause a program crash or arbitrary control of resource allocation, leading to excessive consumption of resources such as memory and CPU.
Confidentiality
Technical Impact: Read Memory; Read Files or Directories
An attacker could read confidential data if they are able to control resource references.
Integrity,Confidentiality,Availability
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
An attacker could use malicious input to modify data or possibly alter control flow in unexpected ways, including arbitrary command execution.
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