Описание
setup before version 2.11.4-1.fc28 in Fedora and Red Hat Enterprise Linux added /sbin/nologin and /usr/sbin/nologin to /etc/shells. This violates security assumptions made by pam_shells and some daemons which allow access based on a user's shell being listed in /etc/shells. Under some circumstances, users which had their shell changed to /sbin/nologin could still access the system.
Setup in Fedora and Red Hat Enterprise Linux added /sbin/nologin and /usr/sbin/nologin to /etc/shells. This violates security assumptions made by pam_shells and some daemons which allow access based on a user's shell being listed in /etc/shells. Under some circumstances, users which had their shell changed to /sbin/nologin could still access the system.
Отчет
Preventing a user from accessing the system without deleting their account is not a simple matter. For utmost security, the account should be deleted. Short of this, we recommend a three-pronged approach:
- change the user's login shell to a harmless command that is not in "/etc/shells" (for example "/bin/false") to prevent commands being run on their behalf
- lock the user's password with "usermod -L" to prevent authentication with pam services
- prevent access to the user's home directory with "chmod 0" or "chown root" and "chmod 700" to prevent authentication with ssh keys etc
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 5 | setup | Will not fix | ||
| Red Hat Enterprise Linux 6 | setup | Fix deferred | ||
| Red Hat Enterprise Linux 8 | setup | Not affected | ||
| Red Hat Enterprise Linux 7 | setup | Fixed | RHSA-2018:3249 | 30.10.2018 |
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Дополнительная информация
Статус:
EPSS
4.8 Medium
CVSS3
Связанные уязвимости
setup before version 2.11.4-1.fc28 in Fedora and Red Hat Enterprise Linux added /sbin/nologin and /usr/sbin/nologin to /etc/shells. This violates security assumptions made by pam_shells and some daemons which allow access based on a user's shell being listed in /etc/shells. Under some circumstances, users which had their shell changed to /sbin/nologin could still access the system.
setup before version 2.11.4-1.fc28 in Fedora and Red Hat Enterprise Linux added /sbin/nologin and /usr/sbin/nologin to /etc/shells. This violates security assumptions made by pam_shells and some daemons which allow access based on a user's shell being listed in /etc/shells. Under some circumstances, users which had their shell changed to /sbin/nologin could still access the system.
Уязвимость модуля pam_shells пакета файлов конфигурации и настройки системы Setup операционных систем Red Hat Enterprise Linux и Fedora, позволяющая нарушителю получить несанкционированный доступ к защищаемой информации
EPSS
4.8 Medium
CVSS3