Vulnerability 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
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Sudo | Sudo | <= 1.8.29 |
References
- https://access.redhat.com/security/cve/cve-2019-19234
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- 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-k2
- https://www.oracle.com/security-alerts/bulletinapr2020.html
FAQ
What is CVE-2019-19234?
CVE-2019-19234 is a vulnerability with a CVSS score of 7.5 (HIGH). 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 ...
How severe is CVE-2019-19234?
CVE-2019-19234 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2019-19234?
Check the references section above for vendor advisories and patch information. Affected products include: Sudo Sudo.