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Buffalo AirStation Extreme N600 Router WZR-600DHP2 uses insufficiently random values for DNS queries

Vulnerability Note VU#646008

Original Release Date: 2015-12-10 | Last Revised: 2016-01-25


Buffalo AirStation Extreme N600 Router WZR-600DHP2, firmware versions 2.09, 2.13, 2.16, and possibly others, uses insufficiently random values for DNS queries and is vulnerable to DNS spoofing attacks.


CWE-330: Use of Insufficiently Random Values - CVE-2015-8262

The Buffalo AirStation Extreme N600 Router WZR-600DHP2 uses static source ports and predictable TXIDs that increment from 0x0002 for all DNS queries originating from the local area network (LAN). An attacker with the ability to spoof DNS responses can cause WZR-600DHP2 LAN clients to contact incorrect or malicious hosts under the attacker's control.

The following graph shows a distribution of 300 DNS queries captured on the WAN port of the WZR-600DHP2:


A remote, unauthenticated attacker may be able to spoof DNS responses to cause WZR-600DHP2 LAN clients to contact attacker-controlled hosts.


Apply an update

The vendor has released firmware version 2.17 to address this vulnerability. Users should review the readme and update affected devices to the latest release.

Vendor Information

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Buffalo Inc

Notified:  July 01, 2015 Updated:  December 10, 2015



Vendor Statement

No statement is currently available from the vendor regarding this vulnerability.

Vendor Information

We are not aware of further vendor information regarding this vulnerability.


There are no additional comments at this time.

If you have feedback, comments, or additional information about this vulnerability, please send us email.

CVSS Metrics

Group Score Vector
Base 5.0 AV:N/AC:L/Au:N/C:N/I:P/A:N
Temporal 4.5 E:POC/RL:U/RC:C
Environmental 1.1 CDP:ND/TD:L/CR:ND/IR:ND/AR:ND



These vulnerabilities were reported by Joel Land of the CERT/CC.

This document was written by Joel Land.

Other Information

CVE IDs: CVE-2015-8262
Date Public: 2015-12-10
Date First Published: 2015-12-10
Date Last Updated: 2016-01-25 17:54 UTC
Document Revision: 13

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