CVE-2021-43566
Published: 11 January 2022
All versions of Samba prior to 4.13.16 are vulnerable to a malicious client using an SMB1 or NFS race to allow a directory to be created in an area of the server file system not exported under the share definition. Note that SMB1 has to be enabled, or the share also available via NFS in order for this attack to succeed.
Mitigation
This issue can be mitigated by disabling SMB1, which is the default configuration in Samba 4.11 and above. In environments where SMB1 cannot be disabled, symlink support can be disabled with unix extensions = no.
Priority
Status
| Package | Release | Status |
|---|---|---|
|
samba Launchpad, Ubuntu, Debian |
jammy |
Released
(4.13.17~dfsg-0ubuntu1)
|
| kinetic |
Released
(4.13.17~dfsg-0ubuntu1)
|
|
| trusty |
Needs triage
|
|
| xenial |
Needs triage
|
|
| bionic |
Needed
|
|
| upstream |
Released
(4.13.16)
|
|
| hirsute |
Ignored
(end of life)
|
|
| focal |
Released
(2:4.13.17~dfsg-0ubuntu0.21.04.1)
|
|
| impish |
Released
(2:4.13.17~dfsg-0ubuntu0.21.10.1)
|
|
| lunar |
Released
(4.13.17~dfsg-0ubuntu1)
|
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 2.5 |
| Attack vector | Local |
| Attack complexity | High |
| Privileges required | Low |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | None |
| Integrity impact | Low |
| Availability impact | None |
| Vector | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N |