Advisory ID: cisco-sa-20030507-vpn3kRevision 1.2
For Public Release 2003 May 7 16:00 UTC (GMT)
This advisory documents vulnerabilities for the Cisco VPN 3000 series
concentrators and Cisco VPN 3002 Hardware Client. These vulnerabilities are
documented as Cisco bug ID CSCea77143 (IPSec over TCP), CSCdz15393 (SSH), and
CSCdt84906 (ICMP). There are workarounds available to mitigate the effects of
these vulnerabilities. Upgrading to the latest version of code for the Cisco
VPN 3000 series concentrators and Cisco VPN 3002 Hardware Client, version 4.0.1
and 3.6.7F, would protect against all of these documented vulnerabilities.
This advisory will be posted at
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20030507-vpn3k.
This section provides details on affected products.
The Cisco VPN 3000 series concentrators are affected by these
vulnerabilities. This series includes models 3005, 3015, 3030, 3060, 3080 and
the Cisco VPN 3002 Hardware Client.
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DDTS - Description
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Affected Releases
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CSCea77143 - enabling IPSec over TCP
vulnerability
|
-
4.0.REL
-
3.6.REL through 3.6.7E
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3.5.x
-
3.1.x, 3.0.x and 2.x.x are NOT
affected.
|
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CSCdz15393 - malformed SSH initialization packet
vulnerability
|
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3.6.REL through 3.6.6
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3.5.x
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3.1.x
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3.0.x
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2.x.x
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CSCdt84906 - malformed ICMP traffic vulnerability
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3.6.REL through 3.6.7
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3.5.x
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3.1.x
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3.0.x
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2.x.x
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To determine if a Cisco VPN 3000 series concentrator is running
affected software, check the software revision via the web interface or the
console menu.
These vulnerabilities do not affect the VPN Client software nor the
Cisco VPN 5000 series concentrators. No other Cisco products are currently
known to be affected by these vulnerabilities.
This table provides details about these vulnerability.
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DDTS - Description
|
Details
|
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CSCea77143 - enabling IPSec over TCP
vulnerability
|
Enabling IPSec over TCP for a port on the VPN 3000 series
concentrator allows TCP traffic on that port to traverse through the
concentrator and reach the private network.
For example, if one configures IPSec over TCP to use port 80 and
the private network is routable to from the public network i.e. a workstation
on the public network has the VPN 3000 series concentrator configured as the
gateway for the private network IP address space, one can browse the web
servers on the private network configured to serve port 80 from the workstation
on the public network without any form of authentication. Another example, if
IPSec over TCP was not configured for port 80 but was configured for its
default port of 10000 and if there was a server listening for telnet
connections on port 10000 on the private network, then one could telnet to that
server from the workstation on the public network.
For more information on IPSec over TCP please refer to the
documentation available at
/en/US/products/hw/vpndevc/ps2284/products_configuration_guide_chapter09186a008015ce2c.html#1279809
|
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CSCdz15393 - malformed SSH initialization packet
vulnerability
|
A malformed SSH initialization packet sent during the initial SSH
session setup may reload the VPN 3000 series concentrator.
|
|
CSCdt84906 - malformed ICMP traffic vulnerability
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A flood of malformed ICMP packets could result in performance
degradation on the VPN 3000 series concentrator and may even cause the
concentrator to reload.
|
These vulnerabilities are documented in the Cisco
Bug Toolkit
(
registered customers only)
as Bug IDs CSCea77143, CSCdz15393, and CSCdt84906, and can
be viewed after 2003 May 8 at 1600 UTC. To access this tool, you must be a
registered user and you must be logged in.
The Inter networking Terms and Cisco Systems Acronyms online guides
can be found at http://www.cisco.com/univercd/cc/td/doc/cisintwk/.
Successful exploitation of the vulnerability may result in the issues
described in this table.
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DDTS - Description
|
Impact
|
|
CSCea77143 - enabling IPSec over TCP
vulnerability
|
Unintended access to the private network on the VPN 3000 series
concentrator. This vulnerability enables one to access internal hosts on the
IPSec over TCP configured ports.
|
|
CSCdz15393 - malformed SSH initialization packet
vulnerability
|
This vulnerability can be exploited to initiate a Denial of
Service on the VPN 3000 series concentrator.
|
|
CSCdt84906 - malformed ICMP traffic vulnerability
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This vulnerability may cause a performance degradation on the VPN
3000 series concentrator and may even result in a Denial of
Service.
|
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.
|
DDTS - Description
|
Fixed Releases
|
|
CSCea77143 - enabling IPSec over TCP
vulnerability
|
-
4.0.1 and later
-
3.6.7F and later
-
3.1.x, 3.0.x and 2.x.x are NOT
affected
|
|
CSCdz15393 - malformed SSH initialization packet
vulnerability
|
-
4.0.REL and later
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3.6.7 and later
|
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CSCdt84906 - malformed ICMP traffic vulnerability
|
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4.0.REL and later
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3.6.7A and later
|
The procedure to upgrade to the fixed software version is detailed at
http://www.cisco.com/univercd/cc/td/doc/product/vpn/vpn3000/.
The Cisco PSIRT recommends that affected users upgrade to a fixed
software version of code.
|
DDTS - Description
|
Workaround
|
|
CSCea77143 - enabling IPSec over TCP
vulnerability
|
Add rules, to the filter for the private interface, that restrict
outgoing traffic on ports configured for use by IPSec over TCP on the VPN
concentrator. This would not stop the traffic from the public network reaching
the VPN 3000 concentrator itself but would prevent the traffic from reaching
the servers on the private network.
|
|
CSCdz15393 - malformed SSH initialization packet
vulnerability
|
Restrict access to the SSH server on the VPN 3000 series
concentrator by applying appropriate rules to the filters for the interfaces
such that connections are permitted only from trusted client hosts.
|
|
CSCdt84906 - malformed ICMP traffic vulnerability
|
Only allow legitimate ICMP traffic to reach the VPN 3000 series
concentrator's interface.
|
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/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 either "psirt@cisco.com" or "security-alert@cisco.com"
for software upgrades.
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 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 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@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/en/US/support/tsd_cisco_worldwide_contacts.html
for additional TAC contact information, including special localized telephone
numbers and instructions and e-mail addresses for use in various
languages.
The Cisco PSIRT is not aware of any public announcements or malicious
use of the vulnerabilities described in this advisory.
These vulnerabilities were reported to PSIRT by internal development
testing.
The Cisco PSIRT is not aware of any public announcements or malicious
use of the vulnerability described in this advisory.
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.
This advisory will be posted on Cisco's worldwide website at
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20030507-vpn3k..
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.
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cust-security-announce@cisco.com
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bugtraq@securityfocus.com
-
first-teams@first.org (includes CERT/CC)
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cisco@spot.colorado.edu
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comp.dcom.sys.cisco
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firewalls@lists.gnac.com
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Various internal Cisco mailing lists
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.
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Revision 1.0
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2003-May-7
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Initial public release.
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Revision 1.1
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2003-May-7
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Corrected the Affected Products table.
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Revision 1.2
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2003-May-8
|
Corrected the link in the Obtaining Fixed Software
section.
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