CVE-2018-1113 – setup: nologin listed in /etc/shells violates security expectations

https://notcve.org/view.php?id=CVE-2018-1113

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 en versiones anteriores a la 2.11.4-1.fc28 en Fedora y Red Hat Enterprise Linux añadía /sbin/nologin y /usr/sbin/nologin a /etc/shells. Esto viola las asunciones de seguridad realizadas por pam_shells y algunos demonios, lo que permite el acceso en base a que el shell de un usuario se lista en /etc/shells. En algunas circunstancias, los usuarios a los que se les haya cambiado el shell a /sbin/nologin podrían seguir siendo capaces de acceder al sistema. • https://access.redhat.com/errata/RHBA-2019:0327 https://access.redhat.com/errata/RHSA-2018:3249 https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-1113 https://access.redhat.com/security/cve/CVE-2018-1113 https://bugzilla.redhat.com/show_bug.cgi?id=1571094 • CWE-285: Improper Authorization CWE-732: Incorrect Permission Assignment for Critical Resource •