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SFTPGo vulnerable to recovery codes abuse

High severity GitHub Reviewed Published Sep 1, 2022 in drakkan/sftpgo • Updated Jan 27, 2023

Package

gomod github.com/drakkan/sftpgo/v2 (Go)

Affected versions

>= 2.2.0, < 2.3.4

Patched versions

2.3.4

Description

Impact

SFTPGo WebAdmin and WebClient support login using TOTP (Time-based One Time Passwords) as a seconday authentication factor. Because TOTPs are often configured on mobile devices that can be lost, stolen or damaged, SFTPGo also supports recovery codes. These are a set of one time use codes that can be used instead of the TOTP.

In SFTPGo versions from v2.2.0 to v2.3.3 recovery codes can be generated before enabling two-factor authentication.
An attacker who knows the user's password could potentially generate some recovery codes and then bypass two-factor authentication after it is enabled on the account at a later time.

Patches

Fixed in v2.3.4.
Recovery codes can now only be generated after enabling two-factor authentication and are deleted after disabling it.

Workarounds

Regenerate recovery codes after enabling two-factor authentication.

References

drakkan/sftpgo#965

References

@drakkan drakkan published to drakkan/sftpgo Sep 1, 2022
Published by the National Vulnerability Database Sep 2, 2022
Published to the GitHub Advisory Database Sep 16, 2022
Reviewed Sep 16, 2022
Last updated Jan 27, 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
Low

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:L

EPSS score

0.070%
(31st percentile)

Weaknesses

CVE ID

CVE-2022-36071

GHSA ID

GHSA-54qx-8p8w-xhg8

Source code

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