Ubuntu update for Samba

1) Security restrictions bypass

EUVDB-ID: #VU101

Risk: High

CVSSv4.0: 6.8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2016-2119

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Exploit availability: No

Description

The vulnerability allows a remote attacker to downgrade client signing security controls on the target system.

The vulnerability exists due to state error in Samba. A remote unauthenticated attacker can downgrade the required signing for an SMB2/3 client connection by injecting the SMB2_SESSION_FLAG_IS_GUEST or SMB2_SESSION_FLAG_IS_NULL flags.

Successful exploitation of this vulnerability may result in disclosure of system information.

Mitigation

Update the affected packages

Ubuntu 16.04 LTS:

samba 2:4.3.11+dfsg-0ubuntu0.16.04.1

Ubuntu 14.04 LTS:

samba 2:4.3.11+dfsg-0ubuntu0.14.04.1

Vulnerable software versions

Ubuntu: 14.04 - 16.04

CPE2.3

• cpe:2.3:o:canonical:ubuntu:14.04:*:*:*:*:*:*:*
• cpe:2.3:o:canonical:ubuntu:16.04:*:*:*:*:*:*:*

External links

https://www.ubuntu.com/usn/usn-3092-1/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

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