Ubuntu update for Samba

1) Symlink attack

EUVDB-ID: #VU18149

Risk: Low

CVSSv3.1: 4 [CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-3880

CWE-ID: CWE-61 - UNIX Symbolic Link (Symlink) Following

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass certain security restrictions.

The vulnerability exists due to a symlink following issue within the RPC endpoint emulating the Windows registry service API. A remote unprivileged attacker with ability to create a symlink can create a new registry hive file anywhere they have unix permissions to create a new file within a Samba share.

Successful exploitation of this vulnerability may allow an attacker to detect presence of exiting files on the system or perform phishing attacks and trick other users to upload files into insecure locations.

Mitigation

Update the affected packages.

Ubuntu 18.10

libsmbclient - 2:4.8.4+dfsg-2ubuntu2.3

samba - 2:4.8.4+dfsg-2ubuntu2.3

Ubuntu 18.04 LTS

libsmbclient - 2:4.7.6+dfsg~ubuntu-0ubuntu2.9

samba - 2:4.7.6+dfsg~ubuntu-0ubuntu2.9

Ubuntu 16.04 LTS

libsmbclient - 2:4.3.11+dfsg-0ubuntu0.16.04.19

samba - 2:4.3.11+dfsg-0ubuntu0.16.04.19

Ubuntu 14.04 LTS

libsmbclient - 2:4.3.11+dfsg-0ubuntu0.14.04.20

samba - 2:4.3.11+dfsg-0ubuntu0.14.04.20

Vulnerable software versions

samba (Ubuntu package): 2:4.3.6+dfsg-1 - 2:4.8.5+dfsg-1

External links

http://usn.ubuntu.com/3939-1/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the local network (LAN).

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.