Vulnerability Note VU#893726
Zyxel P660 series modem/router denial of service vulnerability
Original Release date: 01 Apr 2014 | Last revised: 01 Apr 2014

Overview
Zyxel P660 series modem/router contains a denial of service vulnerability when parsing a high volume of SYN packets on the web management interface.

Description
It has been reported that Zyxel P660 series modem/router (and possibly other models which share the same core firmware) fail to parse a high volume of SYN packets on the web management interface correctly causing the device to reboot. By default, the device runs a web management interface on port tcp/80 which is accessible remotely (LAN and WAN sides).

Impact
An unauthenticated attacker can cause the device to reboot and become unavailable by sending a stream of SYN packets to the device’s web management interface.

Solution
We are currently unaware of a practical solution to this problem.
Restrict Network Access

As a general good security practice, only allow connections from trusted hosts and networks if possible. Restricting access would prevent an attacker from connecting to the service from a blocked network location.

Vendor Information (Learn More)
VendorStatusDate NotifiedDate UpdatedZyXELAffected17 Jun 201331 Jul 2013If you are a vendor and your product is affected, let
us know.

CVSS Metrics (Learn More)

Group
Score
Vector

Base
7.1
AV:N/AC:M/Au:N/C:N/I:N/A:C

Temporal
5.4
E:U/RL:U/RC:UC

Environmental
4.1
CDP:ND/TD:M/CR:ND/IR:ND/AR:ND

References

http://www.zyxel.com/products_services/p_660h_series.shtml?t=p

Credit

Thanks to Alex French for reporting this vulnerability.
This document was written by Michael Orlando.

Other Information

CVE IDs:
CVE-2013-3588

Date Public:
06 Aug 2013

Date First Published:
01 Apr 2014

Date Last Updated:
01 Apr 2014

Document Revision:
11

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