[cisco-voip] FW: [c-nsp] Cisco Security Advisory: Fixed SNMP Communities and OpenUDP Port in Cisco 7920 Wireless IP Phone

Voll, Scott Scott.Voll at wesd.org
Wed Nov 16 11:51:40 EST 2005


Did everyone see this?

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Cisco Security Advisory: Fixed SNMP Communities and Open UDP Port in
Cisco 7920
Wireless IP Phone

Document ID: 68179

Advisory ID: cisco-sa-20051116-7920

http://www.cisco.com/warp/public/707/cisco-sa-20051116-7920.shtml

Revision 1.0

For Public Release 2005 November 16 1600 UTC (GMT)

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Contents
========

    Summary
    Affected Products
    Details
    Impact
    Software Versions and Fixes
    Workarounds
    Obtaining Fixed Software
    Exploitation and Public Announcements
    Status of This Notice: FINAL
    Distribution
    Revision History
    Cisco Security Procedures

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Summary
=======

The Cisco 7920 Wireless IP Phone provides Voice Over IP service via IEEE
802.11b Wi-Fi networks and has a form-factor similar to a cordless
phone. This
product contains two vulnerabilities:

The first vulnerability is an SNMP service with fixed community strings
that
allow remote users to read, write, and erase the configuration of an
affected
device.

The second vulnerability is an open VxWorks Remote Debugger on UDP port
17185
that may allow an unauthenticated remote user to access debugging
information
or cause a denial of service.

Cisco has made free software available to address these vulnerabilities
for
affected customers. There are workarounds available to mitigate the
effects of
the vulnerability.

This advisory is posted at 
http://www.cisco.com/warp/public/707/cisco-sa-20051116-7920.shtml.

Affected Products
=================

Vulnerable Products
+------------------

  * Cisco 7920 Wireless IP Phone, firmware version 2.0 and earlier

Products Confirmed Not Vulnerable
+--------------------------------

  * Cisco 7920 Wireless IP Phone, firmware version 2.01

No other Cisco products are currently known to be affected by these
vulnerabilities, including other IP telephony products.

Details
=======

Fixed SNMP Community Strings
+---------------------------

The Cisco 7920 Wireless IP Phone provides an SNMP service with fixed
read-only
and read-write community strings of "public" and "private",
respectively. These
strings cannot be changed by the user and will allow remote users to
issue an
SNMP GetRequest or SetRequest to the phone. SNMP can be used to retrieve
and
modify the device configuration, including stored user data such as
phone book
entries. To address this vulnerability, Cisco has provided updated
software
that removes the SNMP functionality from this product.

This issue is documented in Cisco bug ID CSCsb75186 ( registered
customers
only) .

VxWorks Debugger Port (wdbrpc, 17185/udp)
+----------------------------------------

The Cisco 7920 Wireless IP Phone listens on UDP port 17185 to allow
connections
from a VxWorks debugger. This port may allow remote users to collect
debugging
information or conduct a denial of service attack against an affected
device.
To address this vulnerability, Cisco has provided updated software that
closes
UDP port 17185.

This issue is documented in Cisco bug ID CSCsb38210 ( registered
customers
only) .

Impact
======

Successful exploitation of these vulnerabilities may result in
information
leakage or denial of service attacks against an affected device. In the
case of
the Fixed SNMP Community Strings vulnerability, an attack may take the
form of
erasure or modification of the device configuration and personal user
data.

Software Versions and Fixes
===========================

Cisco has provided free software to address these vulnerabilities;
please
consult the chart below for details.

When considering software upgrades, also consult
http://www.cisco.com/go/psirt
and any subsequent advisories to determine exposure and a complete
upgrade
solution.

In all cases, customers should exercise caution to be certain the
devices to be
upgraded contain sufficient memory and that current hardware and
software
configurations will continue to be supported properly by the new
release. If
the information is not clear, contact the Cisco Technical Assistance
Center
("TAC") or your contracted maintenance provider for assistance.

+---------------------------------------------+
|                    | Affected  |   First    |
|    Cisco Bug ID    | Firmware  |   Fixed    |
|                    | Releases  |  Firmware  |
|                    |           |  Release   |
|--------------------+-----------+------------|
| CSCsb75186 (       | Release   |            |
| registered         | 1.0(8)    | Release    |
| customers only)    | and       | 1.0(9)     |
| (SNMP)             | earlier   |            |
|--------------------+-----------+------------|
| CSCsb38210 (       | Release   |            |
| registered         | 2.0 and   | Release    |
| customers only)    | earlier   | 2.01       |
| (VxWorks)          |           |            |
+---------------------------------------------+

Workarounds
===========

  * For sites that restrict Cisco 7920 phones to one or more known
subnets,
    Access Control Lists (ACLs) can be used to deny traffic to the
affected
    ports.

    The following extended access-list can be adapted to your network.
This
    example assumes that all Cisco 7920 phones are connected to the
    192.168.10.0 network and that all SNMP access is to be restricted to
a
    management station with the IP address of 10.1.1.1:

        access-list 101 permit udp host 10.1.1.1 192.168.10.0 0.0.0.255 
	  range 161 162
        access-list 101 permit udp host 10.1.1.1 192.168.10.0 0.0.0.255 
	  port 17185
        access-list 101 deny udp any 192.168.10.0 0.0.0.255 range 161
162
        access-list 101 deny udp any 192.168.10.0 0.0.0.255 port 17185
        access-list 101 permit ip any any


    The access-list must then be applied to all interfaces using
configuration
    commands such as:

        interface ethernet 0/0
        ip access-group 101 in


  * Infrastructure ACLs (iACL)
    Although it is often difficult to block traffic transiting your
network, it
    is possible to identify traffic which should never be allowed to
target
    your infrastructure devices and block that traffic at the border of
your
    network. Infrastructure ACLs are considered a network security best
    practice and should be considered as a long-term addition to good
network
    security as well as a workaround for this specific vulnerability.
The white
    paper entitled "Protecting Your Core: Infrastructure Protection
Access
    Control Lists" presents guidelines and recommended deployment
techniques
    for iACLs:
    http://www.cisco.com/warp/public/707/iacl.html

Obtaining Fixed Software
========================

Cisco has made free software available to address this vulnerability for
affected customers. Prior to deploying software, customers should
consult their
maintenance provider or check the software for feature set compatibility
and
known issues specific to their environment.

Customers may only install and expect support for the feature sets they
have
purchased. By installing, downloading, accessing or otherwise using such
software upgrades, customers agree to be bound by the terms of Cisco's
software
license terms found at
http://www.cisco.com/public/sw-license-agreement.html,
or as otherwise set forth at Cisco.com Downloads at 
http://www.cisco.com/public/sw-center/sw-usingswc.shtml.

Do not contact either "psirt at cisco.com" or "security-alert at cisco.com"
for
software upgrades.

Customers with Service Contracts
+-------------------------------

Customers with contracts should obtain upgraded software through their
regular
update channels. For most customers, this means that upgrades should be
obtained through the Software Center on Cisco's worldwide website at 
http://www.cisco.com.

Customers using Third-party Support Organizations
+------------------------------------------------

Customers whose Cisco products are provided or maintained through prior
or
existing agreement with third-party support organizations such as Cisco
Partners, authorized resellers, or service providers should contact that
support organization for guidance and assistance with the appropriate
course of
action in regards to this advisory.

The effectiveness of any workaround or fix is dependent on specific
customer
situations such as product mix, network topology, traffic behavior, and
organizational mission. Due to the variety of affected products and
releases,
customers should consult with their service provider or support
organization to
ensure any applied workaround or fix is the most appropriate for use in
the
intended network before it is deployed.

Customers without Service Contracts
+----------------------------------

Customers who purchase direct from Cisco but who do not hold a Cisco
service
contract and customers who purchase through third-party vendors but are
unsuccessful at obtaining fixed software through their point of sale
should get
their upgrades by contacting the Cisco Technical Assistance Center
(TAC). TAC
contacts are as follows.

  * +1 800 553 2447 (toll free from within North America)
  * +1 408 526 7209 (toll call from anywhere in the world)
  * e-mail: tac at cisco.com

Have your product serial number available and give the URL of this
notice as
evidence of your entitlement to a free upgrade. Free upgrades for
non-contract
customers must be requested through the TAC.

Refer to http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml for
additional TAC contact information, including special localized
telephone
numbers and instructions and e-mail addresses for use in various
languages.

Exploitation and Public Announcements
=====================================

This vulnerability was reported to Cisco by Shawn Merdinger and will be
disclosed on November 16, 2005 at the CSI 32^nd Annual Computer Security
conference in Washington, DC. The Cisco PSIRT is not aware of any
malicious use
of the vulnerability described in this advisory.

Status of This Notice: FINAL
============================

THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY
KIND OF
GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR
FITNESS
FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR
MATERIALS
LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT
TO
CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.

A stand-alone copy or Paraphrase of the text of this document that omits
the
distribution URL in the following section is an uncontrolled copy, and
may lack
important information or contain factual errors.

Distribution
============

This advisory is posted on Cisco's worldwide website at 
http://www.cisco.com/warp/public/707/cisco-sa-20051116-7920.shtml.

In addition to worldwide web posting, a text version of this notice is
clear-signed with the Cisco PSIRT PGP key and is posted to the following
e-mail
and Usenet news recipients.

  * cust-security-announce at cisco.com
  * first-teams at first.org
  * bugtraq at securityfocus.com
  * vulnwatch at vulnwatch.org
  * cisco at spot.colorado.edu
  * cisco-nsp at puck.nether.net
  * full-disclosure at lists.grok.org.uk
  * comp.dcom.sys.cisco at newsgate.cisco.com

Future updates of this advisory, if any, will be placed on Cisco's
worldwide
website, but may or may not be actively announced on mailing lists or
newsgroups. Users concerned about this problem are encouraged to check
the
above URL for any updates.

Revision History
================

+---------------------------------------------+
| Revision |                  | Initial       |
| 1.0      | 2005-November-16 | public        |
|          |                  | release.      |
+---------------------------------------------+

Cisco Security Procedures
=========================

Complete information on reporting security vulnerabilities in Cisco
products,
obtaining assistance with security incidents, and registering to receive
security information from Cisco, is available on Cisco's worldwide
website at
http://www.cisco.com/en/US/products/products_security_vulnerability_poli
cy.html
. This includes instructions for press inquiries regarding Cisco
security
notices. All Cisco security advisories are available at 
http://www.cisco.com/go/psirt.

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