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golang.org/x/crypto/ssh Man-in-the-Middle attack

High severity GitHub Reviewed Published Feb 7, 2023 to the GitHub Advisory Database • Updated Apr 19, 2024

Package

gomod golang.org/x/crypto (Go)

Affected versions

< 0.0.0-20170330155735-e4e2799dd7aa

Patched versions

0.0.0-20170330155735-e4e2799dd7aa

Description

The Go SSH library (golang.org/x/crypto/ssh) by default does not verify host keys, facilitating man-in-the-middle attacks if ClientConfig.HostKeyCallback is not set. Default behavior changed in commit e4e2799 to require explicitly registering a hostkey verification mechanism.

References

Published to the GitHub Advisory Database Feb 7, 2023
Reviewed Feb 7, 2023
Last updated Apr 19, 2024

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
High
Privileges required
None
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:H/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(61st percentile)

Weaknesses

No CWEs

CVE ID

CVE-2017-3204

GHSA ID

GHSA-xhjq-w7xm-p8qj

Source code

No known source code
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