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Cisco Security Advisory: Multiple Cisco Unified CallManager
and
Presence Server Denial of Service Vulnerabilities
Advisory ID: cisco-sa-20070328-voip
http://www.cisco.com/warp/public/707/cisco-sa-2
0070328-voip.shtml
Revision 1.0
For Public Release 2007 March 28 1600 UTC (GMT)
-
------------------------------------------------------------
---------
Summary
=======
Cisco Unified CallManager (CUCM) and Cisco Unified Presence
Server
(CUPS) contain multiple vulnerabilities which may result in
the
failure of CUCM or CUPS functionality, resulting in a Denial
of
Service (DoS) condition. There are no workarounds for these
vulnerabilities. Cisco has made free software available to
address
these vulnerabilities for affected customers.
This advisory is posted at
http://www.cisco.com/warp/public/707/cisco-sa-2
0070328-voip.shtml
Affected Products
=================
Vulnerable Products
+------------------
* Cisco Unified CallManager 3.3 versions prior to
3.3(5)SR2a
* Cisco Unified CallManager 4.1 versions prior to
4.1(3)SR4
* Cisco Unified CallManager 4.2 versions prior to
4.2(3)SR1
* Cisco Unified CallManager 5.0 versions prior to
5.0(4a)SU1
* Cisco Unified Presence Server 1.0 versions prior to
1.0(3)
The software version of a CUCM / CUPS system can be
determined by
navigating to Show > Software via the administration
interface.
For CUCM version 5.0 and CUPS version 1.0 systems, the
software
version can also be determined by running the command show
version
active in the Command Line Interface (CLI).
For CUCM version 3.x and 4.x systems, the software version
can be
determined by navigating to Help > About Cisco Unified
CallManager
and selecting the Details button via the administration
interface.
Products Confirmed Not Vulnerable
+--------------------------------
CUCM versions 4.3(1) and 5.1(1) are not affected by any of
the
vulnerabilities described in this advisory. No other Cisco
products
are currently known to be affected by these
vulnerabilities.
Details
=======
Cisco Unified CallManager (CUCM) is the call processing
component of
the Cisco IP telephony solution which extends enterprise
telephony
features and functions to packet telephony network devices
such as IP
phones, media processing devices, voice-over-IP (VoIP)
gateways, and
multimedia applications.
Cisco Unified Presence Server (CUPS) is the identity
tracking
component of the Cisco IP telephony solution which collects
information about a user's availability status, such as
whether or
not you are using a communications device such as a phone at
a
particular time. It also collects information regarding a
user's
communications capabilities, such as whether Web
collaboration or
video conferencing is enabled.
* SCCP/SCCPS Port Scan Denial of Service
Skinny Call Control Protocol (SCCP) is a Cisco proprietary
voice
protocol used to facilitate call management functions
between
CallManager systems and IP phones. SCCP uses TCP port 2000
for
communications. Secure SCCP (SCCPS) running on TCP port 2443
is also
affected. By sending a series of specially-crafted packets
to the
SCCP service port, it may be possible to crash a CallManager
system
resulting in a denial of service affecting voice services.
CUCM
versions 3.x, 4.x and 5.0 are affected by this
vulnerability. CUPS is
not affected by this vulnerability. This issue is documented
in Cisco
Bug ID CSCsf10805.
* ICMP Echo Request Flood Denial of Service
By sending a large amount of ICMP Echo Requests (Ping) to a
CUCM or
CUPS system, it may be possible to cause various CUCM / CUPS
services
to crash resulting in a denial of service affecting voice
services.
CUCM versions 3.x and 4.x are not affected by this
vulnerability,
only CUCM version 5.0 is affected. The CUCM issue is
documented in
Cisco Bug ID CSCsf12698. The CUPS issue is documented in
Cisco Bug ID
CSCsg60930.
* IPSec Manager Denial of Service
The IPSec Manager Service of CUCM and CUPS is responsible
for
maintaining the connections between CUCM / CUPS systems
deployed as a
cluster. By sending a specific UDP packet to the IPSec
Manager
Service on UDP port 8500, it may be possible to cause the
service to
fail. This would impact advanced call features such as call
forwarding and the ability to deploy configuration changes
to CUCM /
CUPS systems in a cluster. Standard call operations
including the
ability to place and receive calls will continue to
function.
Established calls will not be affected. CUCM versions 3.x
and 4.x are
not affected by this vulnerability, only CUCM version 5.0
is
affected. The CUCM issue is documented in Cisco Bug ID
CSCsg20143.
The CUPS issue is documented in Cisco Bug ID CSCsg60949.
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/int
elligence/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/cv
ss
CSCsf10805 - Cisco Unified CallManager SCCP Port Scan Denial
of Service
+-----------------------------------------------------------
-----------
CVSS Base Score: 3.3
Access Vector: Remote
Access Complexity: Low
Authentication: Not Required
Confidentiality Impact: None
Integrity Impact: None
Availability Impact: Complete
Impact Bias: Normal
CVSS Temporal Score: 2.7
Exploitability: Functional
Remediation Level: Official Fix
Report Confidence: Confirmed
CSCsf12698 - Cisco Unified CallManager ICMP Denial of
Service
+-----------------------------------------------------------
-
CVSS Base Score: 3.3
Access Vector: Remote
Access Complexity: Low
Authentication: Not Required
Confidentiality Impact: None
Integrity Impact: None
Availability Impact: Complete
Impact Bias: Normal
CVSS Temporal Score: 2.7
Exploitability: Functional
Remediation Level: Official Fix
Report Confidence: Confirmed
CSCsg60930 - Cisco Unified Presence Server ICMP Denial of
Service
+-----------------------------------------------------------
-----
CVSS Base Score: 3.3
Access Vector: Remote
Access Complexity: Low
Authentication: Not Required
Confidentiality Impact: None
Integrity Impact: None
Availability Impact: Complete
Impact Bias: Normal
CVSS Temporal Score: 2.7
Exploitability: Functional
Remediation Level: Official Fix
Report Confidence: Confirmed
CSCsg20143 - Cisco Unified CallManager IPSec_Mgr UDP Probe
Denial of Service
+-----------------------------------------------------------
----------------
CVSS Base Score: 4.7
Access Vector: Remote
Access Complexity: Low
Authentication: Not Required
Confidentiality Impact: None
Integrity Impact: Partial
Availability Impact: Partial
Impact Bias: Normal
CVSS Temporal Score: 3.9
Exploitability: Functional
Remediation Level: Official Fix
Report Confidence: Confirmed
CSCsg60949 - Cisco Unified Presence Server IPSec_Mgr UDP
Probe Denial of Service
+-----------------------------------------------------------
--------------------
CVSS Base Score: 4.7
Access Vector: Remote
Access Complexity: Low
Authentication: Not Required
Confidentiality Impact: None
Integrity Impact: Partial
Availability Impact: Partial
Impact Bias: Normal
CVSS Temporal Score: 3.9
Exploitability: Functional
Remediation Level: Official Fix
Report Confidence: Confirmed
Impact
======
* SCCP/SCCPS Port Scan Denial of Service
Successful exploitation of this vulnerability may result in
the
failure of CUCM causing a disruption of voice services.
* ICMP Echo Request Flood Denial of Service
Successful exploitation of this vulnerability may result in
the
failure of CUCM / CUPS causing a disruption of voice
services.
* IPSec Manager Denial of Service
Successful exploitation of this vulnerability may result in
the
failure of certain CUCM / CUPS cluster operations including
the
advanced phone services like call forwarding and the
ability
propagate configuration changes between cluster nodes.
Standard voice
services will continue to function normally.
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.
Fixed software for CUCM and CUPS can be obtained here:
CUCM 3.3 - Fixed in 3.3(5)SR2a, available at
http://www.cisco.com/cgi-bin/tablebuild.pl/cal
lmgr-33?psrtdcat20e2
CUCM 4.1 - Fixed in 4.1(3)SR4, available at
http://www.cisco.com/cgi-bin/tablebuild.pl/cal
lmgr-41?psrtdcat20e2
CUCM 4.2 - Fixed in 4.2(3)SR1, available at
http://www.cisco.com/cgi-bin/tablebuild.pl/cal
lmgr-42?psrtdcat20e2
CUCM 5.0 - Fixed in 5.0(4a)SU1, available at
http://www.cisco.com/cgi-bin/tablebuild.pl/cal
lmgr-50?psrtdcat20e2
CUPS 1.0 - Fixed in 1.0(3), available at
http://www.cisco.com/cgi-bin/tablebuild.pl/cups-1
0?psrtdcat20e2
Workarounds
===========
There are no workarounds for these vulnerabilities.
Filtering traffic as follows for affected CUCM / CUPS
systems can be
used as a mitigation technique:
* Permit TCP port 2000 (SCCP) and TCP port 2443 (SCCPS) to
CUCM
systems only from VoIP endpoints.
* ICMP Echo Requests (type 8) should be blocked for CUCM
and CUPS
systems. This may affect network management applications
and
troubleshooting procedures.
* UDP Port 8500 (IPSec Manager) should only be permitted
between
CUCM / CUPS systems configured in a cluster deployment.
The ICMP Echo Request Flood Denial of Service and IPSec
Manager
Denial of Service vulnerabilities, described in this
document may be
exploited by spoofed attacks.
Transit Access Lists can also be deployed at your network
edge as a
potential mitigation technique. Refer to
http:/
/www.cisco.com/warp/public/707/tacl.html for examples on
how to
apply ACLs on Cisco routers and switches for protection.
Additional mitigations that can be deployed on Cisco devices
within
the network are available in the Cisco Applied Intelligence
companion
document for this advisory:
http://www.cisco.com/warp/public/707/cisco-air
-20070328-voip.shtml
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 cisco.com" or
"security-alertcisco.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: taccisco.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 SCCP denial of service vulnerability was reported to
Cisco by a
customer. The ICMP Echo Request and IPSec Manager Service
denial of
service vulnerabilities were discovered internally by
Cisco.
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-2
0070328-voip.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-announcecisco.com
* first-teamsfirst.org
* bugtraqsecurityfocus.com
* vulnwatchvulnwatch.org
* ciscospot.colorado.edu
* cisco-nsppuck.nether.net
* full-disclosurelists.grok.org.uk
* comp.dcom.sys.cisconewsgate.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 | 2007-March-28 | 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/produ
cts/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/g
o/psirt.
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