NULL dereference when processing SMB traffic in Microsoft Windows

Published: 2017-02-03 | Updated: 2017-03-14
Severity Medium
Patch available YES
Number of vulnerabilities 1
CVE ID CVE-2017-0016
CWE ID CWE-476
Exploitation vector Network
Public exploit Public exploit code for vulnerability #1 is available.
Vulnerable software Windows Subscribe
Windows Server
Vendor Microsoft

Security Advisory

This security advisory describes one medium risk vulnerability.

2017-03-14: Severity of this vulnerability was decreased from critical to medium. Added information about security patch.

1) NULL pointer dereference

Severity: Medium

CVSSv3: 9.3 [CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:F/RL:O/RC:C] [PCI]

CVE-ID: CVE-2017-0016

CWE-ID: CWE-476 - NULL Pointer Dereference

Description

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

The vulnerability exists due to a NULL pointer dereference error when processing Server Message Block (SMB) network traffic. A remote attacker can send specially crafted response, containing too many bytes following the structure defined in the SMB2 TREE_CONNECT Response structure and cause the affected system to crash.

Successful exploitation of the vulnerability may allow an attacker to perform a denial of service (DoS) attack.

Note: the exploit code for this vulnerability is publicly available.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Windows: 8.1, 10

Windows Server: 2012, 2012 R2, 2016

CPE External links

http://www.kb.cert.org/vuls/id/867968 
https://github.com/lgandx/PoC/tree/master/SMBv3%20Tree%20Connect
https://technet.microsoft.com/en-us/library/security/MS17-012

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. However, a fully functional exploit for this vulnerability is available.