CVE-2019-19234

high

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.

References

https://access.redhat.com/security/cve/cve-2019-19234

https://quickview.cloudapps.cisco.com/quickview/bug/CSCvs58104

https://quickview.cloudapps.cisco.com/quickview/bug/CSCvs58473

https://quickview.cloudapps.cisco.com/quickview/bug/CSCvs58772

https://quickview.cloudapps.cisco.com/quickview/bug/CSCvs58812

https://quickview.cloudapps.cisco.com/quickview/bug/CSCvs58979

https://quickview.cloudapps.cisco.com/quickview/bug/CSCvs60748

https://security.netapp.com/advisory/ntap-20200103-0004/

https://support2.windriver.com/index.php?page=cve&on=view&id=CVE-2019-19234

https://support2.windriver.com/index.php?page=defects&on=view&id=LIN1018-5505

https://support2.windriver.com/index.php?page=defects&on=view&id=LIN1019-3816

https://www.bsi.bund.de/SharedDocs/Warnmeldungen/DE/CB/2019/12/warnmeldung_cb-k20-0001.html

https://www.sudo.ws/devel.html#1.8.30b2

https://www.sudo.ws/stable.html

https://www.suse.com/security/cve/CVE-2019-19234/

https://www.tenable.com/plugins/nessus/132985

Details

Source: MITRE

Published: 2019-12-19

Updated: 2020-01-30

Risk Information

CVSS v2

Base Score: 5

Vector: AV:N/AC:L/Au:N/C:N/I:P/A:N

Impact Score: 2.9

Exploitability Score: 10

Severity: MEDIUM

CVSS v3

Base Score: 7.5

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Impact Score: 3.6

Exploitability Score: 3.9

Severity: HIGH