Ubuntu update for Samba

1) Race condition

EUVDB-ID: #VU6630

Risk: Low

CVSSv4.0: 2.1 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2017-2619

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Exploit availability: Yes

Description

The vulnerability allows a remote authenticated user to access otherwise restricted files.

The vulnerability exists due to a race condition when processing symlinks, which lead to files outside the shared folder. An attacker with ability to crate a symlink on a network share can access files not exported under the share definition.

Successful exploitation of the vulnerability may allow an attacker to gain access to potentially sensitive data, but requires that server is under heavy load.

Mitigation

Update the affected packages

Ubuntu 17.04:

samba 2:4.5.8+dfsg-0ubuntu0.17.04.1

Vulnerable software versions

Ubuntu: 17.04

CPE2.3

• cpe:2.3:o:canonical:ubuntu:17.04:*:*:*:*:*:*:*

External links

https://www.ubuntu.com/usn/usn-3267-1/

Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.