CVE-2019-19234

Name	CVE-2019-19234
Description	In Sudo through 1.8.29, the fact that a user has been blocked (e.g., by using the ! character in the shadow file instead of a password hash) is not considered, allowing an attacker (who has access to a Runas ALL sudoer account) to impersonate any blocked user. NOTE: The software maintainer believes that this CVE is not valid. Disabling local password authentication for a user is not the same as disabling all access to that user--the user may still be able to login via other means (ssh key, kerberos, etc). Both the Linux shadow(5) and passwd(1) manuals are clear on this. Indeed it is a valid use case to have local accounts that are _only_ accessible via sudo and that cannot be logged into with a password. Sudo 1.8.30 added an optional setting to check the _shell_ of the target user (not the encrypted password!) against the contents of /etc/shells but that is not the same thing as preventing access to users with an invalid password hash
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs	947225

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
sudo (PTS)	jessie, jessie (lts)	1.8.10p3-1+deb8u9	vulnerable
	stretch (security)	1.8.19p1-2.1+deb9u3	vulnerable
	stretch (lts), stretch	1.8.19p1-2.1+deb9u6	vulnerable
	buster (security), buster, buster (lts)	1.8.27-1+deb10u6	vulnerable
	bullseye (security), bullseye	1.9.5p2-3+deb11u1	fixed
	bookworm	1.9.13p3-1+deb12u1	fixed
	sid, trixie	1.9.16p1-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
sudo	source	(unstable)	1.8.31-1	unimportant		947225

Notes

https://www.sudo.ws/devel.html#1.8.30b2
Sudo 1.8.30 adds an optional setting to check the shell of the target user
additionally.
[wheezy] - sudo <no-dsa> (Minor issue, requires Runas ALL access)