Oracle Linux: CVE-2019-19232: ELSA-2020-1804: sudo security, bug fix, and enhancement update (MODERATE) (Multiple Advisories)

In Sudo through 1.8.29, an attacker with access to a Runas ALL sudoer account can impersonate a nonexistent user by invoking sudo with a numeric uid that is not associated with any user. NOTE: The software maintainer believes that this is not a vulnerability because running a command via sudo as a user not present in the local password database is an intentional feature. Because this behavior surprised some users, sudo 1.8.30 introduced an option to enable/disable this behavior with the default being disabled. However, this does not change the fact that sudo was behaving as intended, and as documented, in earlier versions
It was found that sudo always allowed commands to be run with unknown user or group ids if the sudo configuration allowed it for example via the "ALL" alias. This could allow sudo to impersonate non-existent account and depending on how applications are configured, could lead to certain restriction bypass. This is now explicitly disabled. A new setting called "allow_unknown_runas_id" was introduced in order to enable this.