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CentOS Linux: CVE-2019-19234: Moderate: sudo security, bug fix, and enhancement update (CESA-2020:1804)

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CentOS Linux: CVE-2019-19234: Moderate: sudo security, bug fix, and enhancement update (CESA-2020:1804)

Severity
5
CVSS
(AV:N/AC:L/Au:N/C:N/I:P/A:N)
Published
12/19/2019
Created
02/06/2021
Added
02/05/2021
Modified
11/08/2023

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

Solution(s)

  • centos-upgrade-sudo
  • centos-upgrade-sudo-debuginfo
  • centos-upgrade-sudo-debugsource

References

  • CVE-2019-19234

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