CVE-2019-19234
Published: 19 December 2019
** 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.
Low
CVSS 3 base score: 7.5
Notes
| Author | Note |
|---|---|
| mdeslaur | upstream sudo has disputed this CVE, sudo works as intended and as documented, so marking this as not-affected. |
References
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-19234
- https://www.sudo.ws/devel.html#1.8.30b2
- https://www.sudo.ws/stable.html
- NVD
- Launchpad
- Debian