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Incorrect Authorization in NATS nats-server

High severity GitHub Reviewed Published Feb 7, 2022 in nats-io/nats-server • Updated Aug 17, 2023

Package

gomod github.com/nats-io/nats-server/v2 (Go)

Affected versions

>= 2.0.0, < 2.7.2

Patched versions

2.7.2
gomod github.com/nats-io/nats-streaming-server (Go)
>= 0.15.0, < 0.24.1
0.24.1

Description

(This advisory is canonically https://advisories.nats.io/CVE/CVE-2022-24450.txt)

Problem Description

NATS nats-server through 2022-02-04 has Incorrect Access Control, with unchecked ability for clients to authorize into any account, because of a coding error in a long-extant experimental feature.

A client crafting the initial protocol-level handshake could, with valid credentials for any account, specify a target account and switch into it immediately. This includes any other tenant, and includes the System account which controls nats-server core operations.

For deployments not using multi-tenancy through NATS Accounts, there is still a vulnerability: normal users are able to choose to be in the System account.

An experimental feature to provide dynamically provisioned sandbox accounts was designed to allow a server administrator to turn on an option to allow clients to dynamically request a brand new account inline at connection time. This feature went nowhere, but lived on in the code and was used by a number of tests; support was never added to any client libraries or to the documentation.

A bug in handling the feature meant that if someone did in fact have valid account credentials, then they could specify any other existing account and they would be assigned into that account.

Release 2.7.2 of nats-server removes the feature.
Because of the lack of client support and absence from protocol documentation, we feel this is safe operationally as well as the safest fix for the code.

Affected versions

NATS Server

  • All 2.x versions up to and including 2.7.1.
  • Fixed with nats-io/nats-server: 2.7.2
  • NATS Server 1.x did not have accounts.
  • Docker image: nats https://hub.docker.com/_/nats

NATS Streaming Server

  • All versions embedding affected NATS Server:
    • Affected: v0.15.0 up to and including v0.24.0
    • Fixed with nats-io/nats-streaming-server: 0.24.1
  • Docker image: nats-streaming https://hub.docker.com/_/nats-streaming

Impact

Existing users could act in any account, including the System account.

Workaround

None.

Solution

Upgrade the NATS server.

References

@philpennock philpennock published to nats-io/nats-server Feb 7, 2022
Published by the National Vulnerability Database Feb 8, 2022
Published to the GitHub Advisory Database Feb 8, 2022
Reviewed Feb 8, 2022
Last updated Aug 17, 2023

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS score

0.087%
(38th percentile)

Weaknesses

CVE ID

CVE-2022-24450

GHSA ID

GHSA-g6w6-r76c-28j7

Source code

Credits

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