CVE Vulnerabilities

CVE-2021-31924

Improper Authentication

Published: May 26, 2021 | Modified: Nov 07, 2023
CVSS 3.x
6.8
MEDIUM
Source:
NVD
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
4.6 MEDIUM
AV:L/AC:L/Au:N/C:P/I:P/A:P
RedHat/V2
RedHat/V3
Ubuntu

Yubico pam-u2f before 1.1.1 has a logic issue that, depending on the pam-u2f configuration and the application used, could lead to a local PIN bypass. This issue does not allow user presence (touch) or cryptographic signature verification to be bypassed, so an attacker would still need to physically possess and interact with the YubiKey or another enrolled authenticator. If pam-u2f is configured to require PIN authentication, and the application using pam-u2f allows the user to submit NULL as the PIN, pam-u2f will attempt to perform a FIDO2 authentication without PIN. If this authentication is successful, the PIN requirement is bypassed.

Weakness

When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

Affected Software

Name Vendor Start Version End Version
Pam-u2f Yubico * 1.1.1 (excluding)

Potential Mitigations

References