Message-id: <20070103.cca@psirt.cisco.com>
Date: Wed, 03 Jan 2007 18:15:00 -0000
From: Cisco Systems Product Security Incident Response Team <psirt@...co.com>
To: full-disclosure@...ts.grok.org.uk
Cc: psirt@...co.com
Subject: Cisco Security Advisory: Multiple Vulnerabilities
	in Cisco Clean Access

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Cisco Security Advisory: Multiple Vulnerabilities in Cisco Clean
Access

Advisory ID: cisco-sa-20070103-CleanAccess

http://www.cisco.com/warp/public/707/cisco-sa-20070103-CleanAccess.shtml

Revision 1.0

For Public Release 2007 January 03 1600 UTC (GMT)

- ---------------------------------------------------------------------

Summary
=======

Cisco Clean Access (CCA) is a software solution that can
automatically detect, isolate, and clean infected or vulnerable
devices that attempt to access your network. It consists of Cisco
Clean Access Manager (CAM) and Cisco Clean Access Server (CAS)
devices that work in tandem.

Cisco Clean Access is affected by the following vulnerabilities:

  * Unchangeable shared secret
  * Readable snapshot files

This advisory is posted at
http://www.cisco.com/warp/public/707/cisco-sa-20070103-CleanAccess.shtml

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

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

The following software releases are vulnerable.

Unchangeable Shared Secret

  * CCA releases 3.6.x - 3.6.4.2
  * CCA releases 4.0.x - 4.0.3.2

Readable Snapshots

  * CCA releases 3.5.x - 3.5.9
  * CCA releases 3.6.x - 3.6.1.1

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

No other Cisco products are known to be affected by the
vulnerabilities described in this Advisory.

Details
=======

Unchangeable Shared Secret
+-------------------------

In order for Cisco Clean Access Manager (CAM) to authenticate to a
Cisco Clean Access Server (CAS), both CAM and CAS must have the same
shared secret. The shared secret is configured during the initial CAM
and CAS setup. Due to this vulnerability the shared secret can not be
properly set nor be changed, and it will be the same across all
affected devices. In order to exploit this vulnerability the
adversary must be able to establish a TCP connection to CAS.

This vulnerability is documented in Cisco Bug ID CSCsg24153.

Readable Snapshots
+-----------------

Manual backups of the database ('snapshots') taken on CAM are
susceptible to brute force download attacks. A malicious user can
guess the file name and download it without authentication. The file
itself is not encrypted or otherwise protected.

This vulnerability is documented in Cisco Bug ID CSCsd48626.

Vulnerability Scoring Details
=============================

Cisco is providing scores for the vulnerabilities in this advisory
based on the Common Vulnerability Scoring System (CVSS). Cisco will
provide a base and temporal score. Customers can then compute
environmental scores to assist in determining the impact of the
vulnerability in individual networks. Cisco PSIRT will set the bias
in all cases to normal. Customers are encouraged to apply the bias
parameter when determining the environmental impact of a particular
vulnerability.

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

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

Cisco Bug IDs:

CSCsg24153 Unchangeable shared secret
+------------------------------------

CVSS Base Score: 8

    Access Vector: Remote
    Access Complexity: High
    Authentication: Not Required
    Confidentiality Impact: Complete
    Integrity Impact: Complete
    Availability Impact: Complete
    Impact Bias: Normal

CVSS Temporal Score: 6.3

    Exploitability: Proof of Concept
    Remediation Level: Official Fix
    Report Confidence: Confirmed

CSCsd48626 Readable snapshot files
+---------------------------------

CVSS Base Score: 10

    Access Vector: Remote
    Access Complexity: Low
    Authentication: Not Required
    Confidentiality Impact: Complete
    Integrity Impact: Complete
    Availability Impact: Complete
    Impact Bias: Normal

CVSS Temporal Score: 8.3

    Exploitability: Functional
    Remediation Level: Official Fix
    Report Confidence: ConfirmedImpact


Unchangeable Shared Secret
+-------------------------

Successful exploitation of the vulnerability may enable a malicious
user to effectively take administrative control of a CAS. After that,
every aspect of CAS can be changed including its configuration and
setup.

Readable Snapshots
+-----------------

The snapshot contains sensitive information that can aide in the
attempts, or be used to compromise the CAM. Among other things, the
snapshot can contain passwords in cleartext. Starting with the
release 3.6.0, passwords are no longer stored in cleartext in the
snapshot files.

Software Version and Fixes
==========================

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.

The following CCA software releases contain the fixes.

Unchangeable Shared Secret
+-------------------------

The following software releases contain the fix for this
vulnerability: 3.6.4.3, 4.0.4 and 4.1.0. All subsequent releases will
contain the fix.

The alternative is to install the patch Patch-CSCsg24153.tar.gz which
is available at
http://www.cisco.com/cgi-bin/tablebuild.pl/cca-patches. This patch
provides the fix only for the Unchangeable Shared Secret issue and
does not addreses any other vulnerability.

Readable Snapshots
+-----------------

The following software releases contain the fix for this
vulnerability: 3.5.10 and 3.6.2. All subsequent releases will contain
the fix.

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

There are no workarounds for these vulnerabilities.

Possible mitigation of threat posed by readable snapshot files is to
remove them from the device shortly after they were created. If the
snapshot file needs to be preserved then it can be moved to a
different computer or archived on a secondary storage. Alternately,
the snapshot file can be deleted from the device.

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

Cisco will make free software available to address this vulnerability
for affected customers. This advisory will be updated as fixed
software becomes available. 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@...co.com" or "security-alert@...co.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@...co.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
=====================================

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

The readable snapshot issue was reported to Cisco by Chris Hartley
from Ohio State University. The unchangeable shared secret was
discovered while working on a customer's case and is unrelated to the
Mr. Hartley's report.

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-20070103-CleanAccess.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@...co.com
  * first-teams@...st.org
  * bugtraq@...urityfocus.com
  * vulnwatch@...nwatch.org
  * cisco@...t.colorado.edu
  * cisco-nsp@...k.nether.net
  * full-disclosure@...ts.grok.org.uk
  * comp.dcom.sys.cisco@...sgate.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
================

+---------------------------------------+
| 1.0 | 2007-Jan-03 | Initial 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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