Vulnerability identifier: #VU234

Vulnerability risk: Medium

CVSSv3.1: 4.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2015-5370

CWE-ID: CWE-400

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Samba
Server applications / Directory software, identity management

Vendor: Samba

Description
The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper validation of DCE-RPC packets by the DCE-RPC client and server implementations. A remote attacker can downgrade a secure connection to an insecure one and consume a large amount of CPU resources by using man-in-the-middle techniques.

Successful exploitation of this vulnerability may result in a a denial of service.

Mitigation
Install Samba 4.4.1, 4.3.7 and 4.2.10.

Vulnerable software versions

Samba: 3.6.0, 4.3.7, 4.0.0, 4.4.4

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External links
http://www-01.ibm.com/support/docview.wss?uid=swg21986595
http://www.samba.org/samba/security/CVE-2015-5370.html

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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.