Yubico PAM Module before 2.10 performed user authentication when 'use_first_pass' PAM configuration option was not used and the module was configured as 'sufficient' in the PAM configuration. A remote attacker could use this flaw to circumvent common authentication process and obtain access to the account in question by providing a NULL value (pressing Ctrl-D keyboard sequence) as the password string.
| Software | From | Fixed in |
|---|---|---|
| yubico / pam_module | - | 2.10 |
| debian / debian_linux | 8.0 | 8.0.x |
| debian / debian_linux | 9.0 | 9.0.x |
| debian / debian_linux | 10.0 | 10.0.x |