CVE-2023-4091
Published: 10 October 2023
A vulnerability was discovered in Samba, where the flaw allows SMB clients to truncate files, even with read-only permissions when the Samba VFS module "acl_xattr" is configured with "acl_xattr:ignore system acls = yes". The SMB protocol allows opening files when the client requests read-only access but then implicitly truncates the opened file to 0 bytes if the client specifies a separate OVERWRITE create disposition request. The issue arises in configurations that bypass kernel file system permissions checks, relying solely on Samba's permissions.
Notes
| Author | Note |
|---|---|
| mdeslaur | only vulnerable when using non-default configuraton: acl_xattr:ignore system acls = yes |
Priority
Status
| Package | Release | Status |
|---|---|---|
|
samba Launchpad, Ubuntu, Debian |
trusty |
Needs triage
|
| xenial |
Needs triage
|
|
| bionic |
Needs triage
|
|
| upstream |
Needs triage
|
|
| focal |
Released
(2:4.15.13+dfsg-0ubuntu0.20.04.6)
|
|
| jammy |
Released
(2:4.15.13+dfsg-0ubuntu1.5)
|
|
| lunar |
Released
(2:4.17.7+dfsg-1ubuntu2.3)
|
|
| mantic |
Released
(2:4.18.6+dfsg-1ubuntu2.1)
|
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 6.5 |
| Attack vector | Network |
| Attack complexity | Low |
| Privileges required | Low |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | None |
| Integrity impact | High |
| Availability impact | None |
| Vector | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N |