Authentication bypass in Samba

1) Improper Authentication

EUVDB-ID: #VU18438

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2018-16860

CWE-ID: CWE-287 - Improper Authentication

Exploit availability: No

Description

The vulnerability allows a remote authenticated user to compromise vulnerable domain.

The vulnerability exists due to an error within the process of obtaining kerberos ticket for a service from the Kerberos Key Distribution Center (KDC) that involves S4U2Self and S4U2Proxy extensions. A remote authenticated user can impersonate another service on the network and obtain elevated privileges within the domain.

Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable Active Directory implementation.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Samba: 4.0.0 - 4.10.2

External links

http://www.samba.org/samba/security/CVE-2018-16860.html

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).

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

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