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Soft Serve Public Key Authentication Bypass Vulnerability when Keyboard-Interactive SSH Authentication is Enabled

High severity GitHub Reviewed Published Oct 2, 2023 in charmbracelet/soft-serve • Updated Nov 8, 2023

Package

gomod github.com/charmbracelet/soft-serve (Go)

Affected versions

< 0.6.2

Patched versions

0.6.2

Description

Impact

A security vulnerability in Soft Serve could allow an unauthenticated, remote attacker to bypass public key authentication when keyboard-interactive SSH authentication is active, through the allow-keyless setting, and the public key requires additional client-side verification for example using FIDO2 or GPG. This is due to insufficient validation procedures of the public key step during SSH request handshake, granting unauthorized access if the keyboard-interaction mode is utilized. An attacker could exploit this vulnerability by presenting manipulated SSH requests using keyboard-interactive authentication mode. This could potentially result in unauthorized access to the Soft Serve.

Patches

Users should upgrade to the latest Soft Serve version v0.6.2 to receive the patch for this issue.

Workarounds

To workaround this vulnerability without upgrading, users can temporarily disable Keyboard-Interactive SSH Authentication using the allow-keyless setting.

References

charmbracelet/soft-serve#389

References

@aymanbagabas aymanbagabas published to charmbracelet/soft-serve Oct 2, 2023
Published to the GitHub Advisory Database Oct 2, 2023
Reviewed Oct 2, 2023
Published by the National Vulnerability Database Oct 4, 2023
Last updated Nov 8, 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
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

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:N/UI:N/S:U/C:N/I:H/A:N

EPSS score

0.320%
(70th percentile)

Weaknesses

CVE ID

CVE-2023-43809

GHSA ID

GHSA-mc97-99j4-vm2v

Source code

Credits

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