CVE-2019-19234

NameCVE-2019-19234
Description** DISPUTED ** 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
NVD severitymedium
Debian Bugs947225

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
sudo (PTS)stretch (security), stretch1.8.19p1-2.1+deb9u2vulnerable
buster1.8.27-1+deb10u2vulnerable
buster (security)1.8.27-1+deb10u1vulnerable
bullseye, sid1.9.1-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
sudosource(unstable)1.8.31-1unimportant947225

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.

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