Vulnerability Note VU#646008
Buffalo AirStation Extreme N600 Router WZR-600DHP2 uses insufficiently random values for DNS queries
Original Release date: 10 Dec 2015 | Last revised: 25 Jan 2016

Overview
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.

Description
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:

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

Solution
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 (Learn More)

VendorStatusDate NotifiedDate UpdatedBuffalo IncAffected01 Jul 201510 Dec 2015If you are a vendor and your product is affected, let
us know.

CVSS Metrics (Learn More)

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

References

http://www.buffalotech.com/products/wireless/dual-band-routers/airstation-extreme-n600-router
http://www.buffalotech.com/support-and-downloads/download/wzr600dhp2-us-217.zip
http://www.buffalotech.com/support-and-downloads/download/wzr600dhp2-us-217.txt

Credit

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:
10 Dec 2015

Date First Published:
10 Dec 2015

Date Last Updated:
25 Jan 2016

Document Revision:
13

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