CVE-2017-2619
A race condition was found in samba server. A malicious samba client could use this flaw to access files and directories in areas of the server file system not exported under the share definitions.
Find out more about CVE-2017-2619 from the MITRE CVE dictionary dictionary and NIST NVD.
CVSS v3 metrics
| CVSS3 Base Score | 5.9 |
|---|---|
| CVSS3 Base Metrics | CVSS:3.0/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:L/A:L |
| Attack Vector | Network |
| Attack Complexity | High |
| Privileges Required | Low |
| User Interaction | Required |
| Scope | Unchanged |
| Confidentiality | High |
| Integrity Impact | Low |
| Availability Impact | Low |
Red Hat Security Errata
| Platform | Errata | Release Date |
|---|---|---|
| Red Hat Gluster 3.3 Samba on RHEL-6 (samba) | RHSA-2017:2778 | 2017-09-21 |
| Red Hat Gluster 3.2 Samba on RHEL-7 (samba) | RHSA-2017:2338 | 2017-08-01 |
| Red Hat Enterprise Linux 6 (samba) | RHSA-2017:2789 | 2017-09-21 |
| Red Hat Enterprise Linux 7 (samba) | RHSA-2017:1265 | 2017-05-22 |
Affected Packages State
| Platform | Package | State |
|---|---|---|
| Red Hat Enterprise Linux 6 | samba4 | Will not fix |
| Red Hat Enterprise Linux 5 | samba | Will not fix |
| Red Hat Enterprise Linux 5 | samba3x | Will not fix |
Acknowledgements
Red Hat would like to thank the Samba project for reporting this issue. Upstream acknowledges Jann Horn (Google) as the original reporter.Mitigation
Add the parameter:
unix extensions = no
to the [global] section of your smb.conf and restart smbd. This prevents SMB1 clients from creating symlinks on the exported file system using SMB1.
However, if the same region of the file system is also exported using NFS, NFS clients can create symlinks that potentially can also hit the race condition. For non-patched versions of Samba we recommend only exporting areas of the file system by either SMB or NFS, not both.