An issue was discovered in the selinux-policy (aka Reference Policy) package 3.14 through 2020-08-24 because the .config/Yubico directory is mishandled. Consequently, when SELinux is in enforced mode, pam-u2f is not allowed to read the users U2F configuration file. If configured with the nouserok option (the default when configured by the authselect tool), and that file cannot be read, the second factor is disabled. An attacker with only the knowledge of the password can then log in, bypassing 2FA.
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 |
|---|---|---|---|
| Selinux-policy | Fedoraproject | 3.14 (including) | 2020-08-24 (including) |
| Refpolicy | Ubuntu | bionic | * |
| Refpolicy | Ubuntu | focal | * |
| Refpolicy | Ubuntu | groovy | * |
| Refpolicy | Ubuntu | hirsute | * |
| Refpolicy | Ubuntu | impish | * |
| Refpolicy | Ubuntu | kinetic | * |
| Refpolicy | Ubuntu | lunar | * |
| Refpolicy | Ubuntu | mantic | * |
| Refpolicy | Ubuntu | oracular | * |
| Refpolicy | Ubuntu | plucky | * |
| Refpolicy | Ubuntu | trusty | * |
| Refpolicy | Ubuntu | trusty/esm | * |
| Refpolicy | Ubuntu | xenial | * |
Potential Mitigations
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/114.html
- https://cwe.mitre.org/data/definitions/115.html
- https://cwe.mitre.org/data/definitions/151.html
- https://cwe.mitre.org/data/definitions/194.html
- https://cwe.mitre.org/data/definitions/22.html
- https://cwe.mitre.org/data/definitions/57.html
- https://cwe.mitre.org/data/definitions/593.html
- https://cwe.mitre.org/data/definitions/633.html
- https://cwe.mitre.org/data/definitions/650.html
- https://cwe.mitre.org/data/definitions/94.html