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Cisco Security Advisory: Cisco Security Agent for Windows System Driver
Remote Buffer Overflow Vulnerability
Advisory ID: cisco-sa-20071205-csa
http://www.cisco.com/warp/public/707/cisco-sa-20071205-csa.shtml
Revision 1.0
For Public Release 2007 December 05 1600 UTC (GMT)
+---------------------------------------------------------------------
Summary
=======
A buffer overflow vulnerability exists in a system driver used by the
Cisco Security Agent for Microsoft Windows. This buffer overflow can be
exploited remotely and causes corruption of kernel memory, which leads
to a Windows stop error (blue screen) or to arbitrary code execution.
The vulnerability is triggered during processing of a crafted TCP
segment destined to TCP port 139 or 445. These ports are used by the
Microsoft Server Message Block (SMB) protocol.
Cisco has released free software updates that address this
vulnerability.
Common Vulnerabilities and Exposures (CVE) identifier CVE-2007-5580 has
been assigned to this vulnerability.
This advisory is posted at
http://www.cisco.com/warp/public/707/cisco-sa-20071205-csa.shtml.
Affected Products
=================
Vulnerable Products
+------------------
All versions of Cisco Security Agent for Windows, either managed
or standalone, are affected. Agents that are running on Cisco IP
Communications application servers or agents on systems that are running
the Cisco Security Manager are examples of a standalone implementation.
Standalone agents are installed in the following Cisco IP Communications
products:
* Cisco Unified Communications Manager (CallManager)
* Cisco Conference Connection (CCC)
* Emergency Responder
* IPCC Express
* IPCC Enterprise
* IPCC Hosted
* IP Interactive Voice Response (IP IVR)
* IP Queue Manager
* Intelligent Contact Management (ICM)
* Cisco Voice Portal (CVP)
* Cisco Unified Meeting Place
* Cisco Personal Assistant (PA)
* Cisco Unity
* Cisco Unity Connection
* Cisco Unity Bridge
* Cisco Internet Service Node (ISN)
Cisco Security Manager installs a standalone version of Cisco Security
Agent if an agent is not found when Cisco Security Manager is installed,
so systems that are running Cisco Security Manager are also affected by
this vulnerability.
Products Confirmed Not Vulnerable
+--------------------------------
The Cisco Secure Access Control Server (ACS) Solution Engine, also
known as the ACS appliance, integrates a standalone version of Cisco
Security Agent. However, the ACS Solution Engine is not affected by
this vulnerability because by default it blocks incoming traffic to
the affected TCP ports (139 and 445). Additional information is in the
Details section.
Cisco Security Agents that are running on the Solaris and Linux
operating systems are not affected by the vulnerability described in
this advisory.
No other Cisco products are currently known to be affected by this
vulnerability.
Details
=======
Cisco Security Agent is a security software agent that provides threat
protection for server and desktop computing systems. Cisco Security
Agents can be managed by a Management Center for Cisco Security Agents
or can be standalone agents that are not managed by a Cisco Security
Agent Management Center.
Some Cisco products integrate standalone Cisco Security Agents to
protect the products against viruses, worms, and attacks. Examples of
products that integrate standalone Cisco Security Agents include Cisco
IP Communications application servers, the Cisco Secure Access Control
Server (ACS) Solution Engine, and the Cisco Security Manager.
A buffer overflow vulnerability exists in a system driver used by Cisco
Security Agents, whether they are managed or unmanaged. Cisco Security
Agents use this driver by default.
Windows kernel memory becomes corrupted when this buffer is overflowed.
Therefore, exploitation of this vulnerability will lead to a Windows
stop error (kernel panic, or blue screen error), or to arbitrary code
execution. The vulnerability can be exploited remotely via the network.
The vulnerability is triggered when Cisco Security Agent is processing
a crafted TCP segment destined to TCP port 139 or 445. These ports are
used by the Microsoft Server Message Block (SMB) protocol. A TCP session
needs to be established (that is, the TCP three-way handshake needs to
be completed) for the vulnerability to be triggered.
All systems that are running a vulnerable version of Cisco Security
Agent for Windows are affected. This includes Cisco products that
integrate standalone Cisco Security Agents, such as Cisco IP
Communications applications servers and the Cisco Security Manager.
Although the ACS Solution Engine integrates a standalone Cisco Security
Agent, it is not affected because TCP ports 139 and 445 have been
firewalled by the ACS Solution Engine itself. This blocking of traffic
destined to TCP ports 139 and 445 is enabled by default and is not
user-configurable.
This vulnerability is documented in Cisco bug ID CSCsl00618.
The CVE identifier CVE-2007-5580 has been assigned to this
vulnerability.
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 a 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.
* Buffer overflow in system driver causes BSOD (CSCsl00618)
CVSS Base Score - 10.0
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 buffer overflow vulnerability described
in this advisory may result in an operating system crash or complete
system compromise.
Software Versions 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.
Managed Cisco Security Agents
+----------------------------
Fixed software for managed Cisco Security Agents is available in the
form of hotfixes. The following table contains hotfix information for
the current supported versions of Cisco Security Agent. Future versions
of Cisco Security Agent will have the fix included.
+----------------------------------------+
| Affected Cisco Security | Hotfix |
| Agent Version | Version |
|--------------------------+-------------|
| 4.5.1 | Hotfix |
| | 4.5.1.672 |
|--------------------------+-------------|
| 5.0 | Hotfix |
| | 5.0.0.225 |
|--------------------------+-------------|
| 5.1 | Hotfix |
| | 5.1.0.106 |
|--------------------------+-------------|
| 5.2 | Hotfix |
| | 5.2.0.238 |
+----------------------------------------+
Cisco Security Agent hotfixes can be downloaded from the following
location:
http://www.cisco.com/cgi-bin/tablebuild.pl/csahf-crypto?psrtdcat20e2
Cisco Security Agent for Cisco IP Communications Products
+--------------------------------------------------------
The following table contains information about Cisco Security Agent
fixes for Cisco IP Communications products:
+--------------------------------------------+
| Affected | |
| Cisco | |
| Security | Fixed Software |
| Agent | |
| Version | |
|----------+---------------------------------|
| 4.5.1 | CUCM-CSA-4.5.1.672-2.0.7-k9.exe |
|----------+---------------------------------|
| 5.0 | CUCM-CSA-5.0.0.225-3.0.7-k9.exe |
+--------------------------------------------+
These fixes can be downloaded from the following location:
http://www.cisco.com/cgi-bin/tablebuild.pl/cmva-3des?psrtdcat20e2
Cisco Security Agent for Cisco Security Manager
+----------------------------------------------
A fixed standalone Cisco Security Agent for the Cisco
Security Manager is provided in the form of the hotfix
fcs-csamc-hotfix-5.2.0.238-w2k3-k9-CSM.zip, which is available for
download from:
http://www.cisco.com/cgi-bin/tablebuild.pl/csm-app?psrtdcat20e2.
Workarounds
===========
General Considerations
+---------------------
Filters that deny SMB protocol packets using TCP ports 139 and 445
should be deployed as part of a transit access control list (tACL)
policy for protection from traffic that enters the network at ingress
access points. This policy should be configured to protect the network
device where the filter is applied and other devices behind it. Filters
for SMB protocol packets using TCP ports 139 and 445 should also be
deployed in front of vulnerable hosts so that traffic is allowed only
from trusted clients.
Additional information about tACLs is available in "Transit Access
Control Lists : Filtering at Your Edge":
http://www.cisco.com/en/US/tech/tk648/tk361/technologies_white_paper09186a00801afc76.shtml
Additional mitigation techniques that can be deployed on Cisco devices
within the network are available in the Cisco Applied Mitigation
Bulletin companion document for this advisory:
http://www.cisco.com/warp/public/707/cisco-amb-20071205-csa.shtml
Cisco Security Agent Rule to Block TCP Port 139 and 445 Traffic
+--------------------------------------------------------------
Workstations that do not have a need to provide SMB services, such as
services for sharing directories or files and printers, can be protected
by configuring a Cisco Security Agent rule that blocks all traffic to
TCP ports 139 and 445 (the SMB ports).
Such a rule exists in versions of Cisco Security Agent that include
the Network Personal Firewall policy. The specific rule can be found
by searching rules for one that has the description "All applications,
server for SMB services (offering network shares)" or by opening the
Personal Firewall Module rule module (attached to the Network Personal
Firewall policy) and editing the rule that has this description. This
rule is enabled by default but the default action must be changed from
Allow to a High Priority Deny.
If the Network Personal Firewall policy is not available, administrators
can create a network access rule that blocks traffic to TCP ports 139
and 445. To do this, the rule must be configured as a Deny rule so
traffic is denied when the system on which Cisco Security Agent is
installed attempts to act as a server for network services on ports TCP
139 and 445. For additional information on configuring Cisco Security
Agent network access control rules, reference the following document:
http://www.cisco.com/en/US/docs/security/csa/csa52/user_guide/Chap6.html#wp1199624.
Caution: Blocking TCP ports 139 and 445 on a Windows system will cause
the Windows system to stop providing SMB services. Before implementing
the workarounds presented in this section, administrators are advised to
ensure that they understand the implications of disabling SMB services
on users' workstations.
Obtaining Fixed Software
========================
Cisco has released free software updates that address these
vulnerabilities. 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/products/prod_warranties_item09186a008088e31f.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@private or security-alert@private 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@private
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/warp/public/687/Directory/DirTAC.shtml
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 reported to Cisco by the NSFocus Security Team
(http://www.nsfocus.com). Cisco would like to thank the NSFocus Security
Team for reporting this vulnerability and working with us towards
resolution of this problem.
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-20071205-csa.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@private
* first-teams@private
* bugtraq@private
* vulnwatch@private
* cisco@private
* cisco-nsp@private
* full-disclosure@private
* comp.dcom.sys.cisco@private
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 1.0 | 2007-December-05 | 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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All contents are Copyright (C) 2006-2007 Cisco Systems, Inc. All rights
reserved.
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