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Hard-Coded SNMP Community Names in Cisco Industrial Ethernet 3000 Series Switches Vulnerability



Cisco Security Advisory: Hard-Coded SNMP Community Names in Cisco Industrial Ethernet 3000 Series Switches Vulnerability
Cisco Security Advisory: Hard-Coded SNMP Community Names in Cisco Industrial Ethernet 3000 Series Switches Vulnerability



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Cisco Security Advisory: Hard-Coded SNMP Community Names in Cisco
Industrial Ethernet 3000 Series Switches Vulnerability

Advisory ID: cisco-sa-20100707-snmp

Revision 1.0

For Public Release 2010 July 07 1600 UTC (GMT)

+---------------------------------------------------------------------

Summary
======
Cisco Industrial Ethernet 3000 (IE 3000) Series switches running
Cisco IOS Software releases 12.2(52)SE or 12.2(52)SE1, contain a
vulnerability where well known SNMP community names are hard-coded
for both read and write access. The hard-coded community names are
"public" and "private."

Cisco recommends that all administrators deploy the mitigation
measures outlined in the Workarounds section or perform a Cisco IOS
Software upgrade.

Cisco has released free software updates that address this
vulnerability.

Workarounds that mitigate this vulnerability are available.

This advisory is posted at:

http://www.cisco.com/warp/public/707/cisco-sa-20100707-snmp.shtml 

Affected Products
================
The following product is affected by this vulnerability:

  * Cisco Industrial Ethernet 3000 Series Switches

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

The Cisco Industrial Ethernet 3000 Series switches are vulnerable
when running any of the following Cisco IOS Software releases:

  * Cisco IOS Software release 12.2(52)SE or 12.2(52)SE1

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

No other Cisco products are currently known to be affected by this
vulnerability.

Other hardware models of Cisco switching products that are running
the vulnerable Cisco IOS Software versions are not affected by this
vulnerability.

Cisco Industrial Ethernet 3000 Series switches that are not running
the Cisco IOS Software releases that is listed above are not
vulnerable.

Details
======
Cisco Industrial Ethernet 3000 Series switches that are running
affected versions of Cisco IOS Software contain hard-coded SNMP
read-write community names.

The Cisco Industrial Ethernet 3000 Series is a family of switches
that provide a rugged, easy-to-use, secure infrastructure for harsh
environments.

SNMP is used for managing and monitoring the device and community
names are the equivalent to a password.

The hard-coded SNMP community names are:

    snmp-server community public RO
    snmp-server community private RW

The SNMP community names can be removed; however, the hard-coded
community names are reapplied to the running configuration when the
device reloads. Cisco has provided a workaround that ensures the
community names are removed when the device reloads.

Note: Configuring an access list or a restricted mib view:

    snmp-server community public RO 99
    snmp-server community private RW 99
    snmp-server community public view  RO 99
    snmp-server community private view  RO 99
    
    access-list 99 deny   any

The proceeding works as a workaround until the device is reloaded.
Once the device is reloaded the original configuration is inserted
without the access lists or mib views assigned to the community
names. Consult the workarounds section of this advisory.

This vulnerability was introduced as part of a new feature integrated
into the affected releases called PROFINET. At the time of the
publication of this advisory, PROFINET was only supported on Cisco
Industrial Ethernet 3000 Series switches.

This vulnerability is documented in the Cisco Bug ID CSCtf25589.
This vulnerability has been assigned Common Vulnerabilities and
Exposures (CVE) ID CVE-2010-1574.

Vulnerability Scoring Details
============================
Cisco has provided scores for the vulnerability in this advisory
based on the Common Vulnerability Scoring System (CVSS). The CVSS
scoring in this Security Advisory is done in accordance with CVSS
version 2.0.

CVSS is a standards-based scoring method that conveys vulnerability
severity and helps determine urgency and priority of response.

Cisco has provided a base and temporal score. Customers can then
compute environmental scores to assist in determining the impact of
the vulnerability in individual networks.

Cisco has provided an FAQ to answer additional questions regarding
CVSS at:

http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html 

Cisco has also provided a CVSS calculator to help compute the
environmental impact for individual networks at:

http://intellishield.cisco.com/security/alertmanager/cvss 

CSCtf25589 - Hard-coded SNMP Community Names in Cisco Industrial Ethernet 3000 Series

CVSS Base Score - 10

Access Vector           - Network
Access Complexity       - Low
Authentication          - None
Confidentiality Impact  - Complete
Integrity Impact        - Complete
Availability Impact     - Complete

CVSS Temporal Score - 8.3

Exploitability          - Functional
Remediation Level       - Official-Fix
Report Confidence       - Confirmed

Impact
=====
Successful exploitation of the vulnerability could result in an
attacker obtaining full control of the device.

Software Versions and Fixes
==========================
When considering software upgrades, 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 ensure 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.

Each row of the Cisco IOS software table (below) names a Cisco IOS
release train. If a given release train is vulnerable, then the
earliest possible releases that contain the fix (along with the
anticipated date of availability for each, if applicable) are listed
in the "First Fixed Release" column of the table. A device running a
release in the given train that is earlier than the release in a
specific column (less than the First Fixed Release) is known to be
vulnerable. Cisco recommends upgrading to a release equal to or later
than the release specified in the "First Fixed Release" column of the
table.

+-------------------------------------------------------------------+
|    Major     |         Availability of Repaired Releases          |
|   Release    |                                                    |
|--------------+----------------------------------------------------|
|   Affected   |                                                    |
|  12.0-Based  |                First Fixed Release                 |
|   Releases   |                                                    |
|-------------------------------------------------------------------|
| There are no affected 12.0 based releases                         |
|-------------------------------------------------------------------|
|   Affected   |                                                    |
|  12.1-Based  |                First Fixed Release                 |
|   Releases   |                                                    |
|-------------------------------------------------------------------|
| There are no affected 12.1 based releases                         |
|-------------------------------------------------------------------|
|   Affected   |                                                    |
|  12.2-Based  |                First Fixed Release                 |
|   Releases   |                                                    |
|--------------+----------------------------------------------------|
|              | Releases prior to 12.2(52)SE are not vulnerable.   |
| 12.2SE       | First fixed in release 12.2(55)SE. Currently       |
|              | scheduled to be available August 2010.             |
|-------------------------------------------------------------------|
| There are no other affected 12.2 based releases                   |
|-------------------------------------------------------------------|
|   Affected   |                                                    |
|  12.3-Based  |                First Fixed Release                 |
|   Releases   |                                                    |
|-------------------------------------------------------------------|
| There are no affected 12.3 based releases                         |
|-------------------------------------------------------------------|
|   Affected   |                                                    |
|  12.4-Based  |                First Fixed Release                 |
|   Releases   |                                                    |
|-------------------------------------------------------------------|
| There are no affected 12.4 based releases                         |
|-------------------------------------------------------------------|
|   Affected   |                                                    |
|  15.0-Based  |                First Fixed Release                 |
|   Releases   |                                                    |
|-------------------------------------------------------------------|
| There are no affected 15.0 based releases                         |
|-------------------------------------------------------------------|
|   Affected   |                                                    |
|  15.1-Based  |                First Fixed Release                 |
|   Releases   |                                                    |
|-------------------------------------------------------------------|
| There are no affected 15.1 based releases                         |
+-------------------------------------------------------------------+

Workarounds
==========
Manually Remove SNMP Community Names
+-----------------------------------

Note: The following workaround is only effective until the device is
reloaded. Upon each reload of the device this workaround must be
re-applied. Cisco encourages performing a Cisco IOS Software upgrade
as a permanent fix for this vulnerability.

Log in to the device, and enter configuration mode. Enter the
following configuration commands:

    no snmp-server community public RO
    no snmp-server community private RW

Saving the configuration will update the start-up configuration
files; however the hard-coded community names will be reinserted to
the running configuration when the device reloads. This workaround
must be applied each time the device is reloaded.

Automatically Remove SNMP Community Names
+----------------------------------------

By creating an Embedded Event Manager (EEM) policy, it is possible to
automatically remove the hard-coded SNMP community names each time
the device is reloaded. The following example shows an EEM policy
that runs each time the device is reloaded and removes the hard-coded
SNMP community names.

    event manager applet cisco-sa-20100707-snmp
     event timer countdown time 30 
     action 10 cli command "enable"
     action 20 cli command "configure terminal"
     action 30 cli command "no snmp-server community public RO"
     action 40 cli command "no snmp-server community private RW"
     action 50 cli command "end"
     action 60 cli command "disable"
     action 70 syslog msg "Hard-coded SNMP community names as per Cisco Security Advisory cisco-sa-20100707-snmp removed"

For more information on EEM policies consult the Cisco IOS Network
Management Configuration Guide - Embedded Event Manager Overview at
the following link:

http://www.cisco.com/en/US/docs/ios/netmgmt/configuration/guide/nm_eem_overview_ps6441_TSD_Products_Configuration_Guide_Chapter.html 

Infrastructure Access Control Lists
+----------------------------------

Although it is often difficult to block traffic that transits a
network, it is possible to identify traffic that should never be
allowed to target infrastructure devices and block that traffic at
the device interface or the border of networks.

If SNMP management is not required on the IE3000, then dropping all
SNMP traffic to the device is a sufficient workaround. The iACL below
shows an example of an IE3000 with two interfaces configured with
layer 3 access, dropping all SNMP queries destined to the IE3000:

    
    !---
    !--- Deny SNMP traffic from all other sources destined to 
    !--- configured IP addresses on the IE3000.
    !---
    
    
    access-list 150 deny udp any host 192.168.0.1 eq snmp
    access-list 150 deny udp any host 192.168.1.1 eq snmp
    
    
    !---
    !--- Permit/deny all other Layer 3 and Layer 4 traffic in 
    !--- accordance with existing security policies and configurations
    !--- Permit all other traffic to transit the device.
    !---
    
    
    access-list 150 permit ip any any
    
    
    !---
    !--- Apply access-list to all Layer 3 interfaces 
    !--- (only two examples shown)
    !---
    
    
    interface Vlan1
     ip address 192.168.0.1 255.255.255.0
     ip access-group 150 in
    
    interface GigabitEthernet1/1
     ip address 192.168.1.1 255.255.255.0
     ip access-group 150 in

The white paper "Protecting Your Core: Infrastructure Protection
Access Control Lists" presents guidelines and recommended deployment
techniques for infrastructure protection access lists. This white
paper can be obtained at the following link:

http://www.cisco.com/en/US/tech/tk648/tk361/technologies_white_paper09186a00801a1a55.shtml 

Obtaining Fixed Software
=======================
Cisco has released free software updates that address this
vulnerability. 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/en/US/docs/general/warranty/English/EU1KEN_.html 

or as otherwise set forth at Cisco.com Downloads at:

http://www.cisco.com/public/sw-center/sw-usingswc.shtml 

Do not contact psirt@cisco.com or security-alert@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 agreements 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 do not hold a Cisco
service contract, and customers who purchase through third-party
vendors but are unsuccessful in obtaining fixed software through
their point of sale should acquire 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@cisco.com 

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

Refer to:

http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html 

for additional TAC contact information, including localized telephone
numbers, and instructions and e-mail addresses for use in various
languages.

Exploitation and Public Announcements
====================================
The Cisco PSIRT is not aware of any public announcements or malicious
use of the vulnerability described in this advisory.

This vulnerability was discovered when handling customer support
calls.

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-20100707-snmp.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@cisco.com 
* first-bulletins@lists.first.org 
* bugtraq@securityfocus.com 
* vulnwatch@vulnwatch.org 
* cisco@spot.colorado.edu 
* cisco-nsp@puck.nether.net 
* full-disclosure@lists.grok.org.uk 
* comp.dcom.sys.cisco@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      | 2010-July-07 | 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_policy.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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