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.
Notes
| Author | Note |
|---|---|
| mdeslaur | upstream sudo has disputed this CVE, sudo works as intended and as documented, so marking this as not-affected. |
Priority
Status
| Package | Release | Status |
|---|---|---|
|
sudo Launchpad, Ubuntu, Debian |
bionic |
Not vulnerable
|
| disco |
Ignored
(end of life)
|
|
| eoan |
Not vulnerable
|
|
| focal |
Released
(1.8.31-1ubuntu1)
|
|
| trusty |
Not vulnerable
|
|
| upstream |
Released
(1.8.30)
|
|
| xenial |
Not vulnerable
|
|
|
Patches: upstream: https://www.sudo.ws/repos/sudo/rev/ed6db31729cd |
||
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 7.5 |
| Attack vector | Network |
| Attack complexity | Low |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | None |
| Integrity impact | High |
| Availability impact | None |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |