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AUSCERT External Security Bulletin Redistribution
ESB-2003.0854 -- Cisco Security Advisory
Cisco FWSM Vulnerabilities
16 December 2003
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AusCERT Security Bulletin Summary
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Product: Cisco Firewall Services Module (FWSM)
Publisher: Cisco Systems
Operating System: Cisco FWSM software 1.1.2 and prior
Platform: Cisco Catalyst 6500 Series
Cisco 7600 Series
Impact: Denial of Service
Access Required: Remote
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Cisco Security Advisory: Cisco FWSM Vulnerabilities
Revision 1.0
For Public Release 2003 December 15 at 1600 UTC (GMT)
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Contents
Summary
Affected Products
Details
Impact
Software Versions and Fixes
Obtaining Fixed Software
Workarounds
Exploitation and Public Announcements
Status of This Notice: Final
Distribution
Revision History
Cisco Security Procedures
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Summary
This advisory documents two vulnerabilities for the Cisco Firewall
Services Module for Cisco Catalyst 6500 Series and Cisco 7600 Series
(FWSM). These vulnerabilities are documented as CSCeb16356 (HTTP Auth) and
CSCeb88419 (SNMPv3).
There are workarounds available to mitigate the effects of CSCeb88419
(SNMPv3). No workaround is available for CSCeb16356 (HTTP Auth).
This advisory will be posted at
http://www.cisco.com/warp/public/707/cisco-sa-20031215-fwsm.shtml.
Affected Products
All Cisco FWSM devices running the affected Cisco FWSM software, as
documented below, are affected by these vulnerabilities.
* CSCeb16356 (HTTP Auth)
1.1.2 and earlier.
* CSCeb88419 (SNMPv3)
1.1.2 and earlier.
The Cisco PIX firewall is also vulnerable to the SNMPv3 issue and is
documented as
http://www.cisco.com/warp/public/707/cisco-sa-20031215-pix.shtml. No other
Cisco products are currently known to be affected by these
vulnerabilities.
To determine your software revision, type show version at the command line
prompt.
Details
* CSCeb16356 (HTTP Auth)
The Cisco FWSM may crash and reload due to a buffer overflow
vulnerability while processing HTTP traffic requests for
authentication using TACACS+ or RADIUS. This request is initiated when
a user starting a connection via FTP, Telnet, or over the World Wide
Web (HTTP) is prompted for their user name and password. If the user
name and password are verified by the designated TACACS+ or RADIUS
authentication server, the Cisco FWSM will allow further traffic
between the authentication server and the connection to interact
independently through the Cisco FWSM's "cut-through proxy" feature.
* CSCeb88419 (SNMPv3)
The Cisco FWSM crashes and reloads while processing a received SNMPv3
message when snmp-server host <ip_addr> is configured on the Cisco
FWSM. This happens even though the Cisco FWSM does not support SNMPv3.
The Internetworking Terms and Cisco Systems Acronyms online guides can be
found at http://www.cisco.com/univercd/cc/td/doc/cisintwk/.
These vulnerabilities are documented in the Cisco Bug Toolkit as Bug ID
CSCeb16356 (HTTP Auth) and CSCeb88419 (SNMPv3). To access this tool, you
must be a registered user and you must be logged in.
Impact
* CSCeb16356 (HTTP Auth)
This vulnerability can be exploited to initiate a Denial of Service
attack on the Cisco FWSM.
* CSCeb88419 (SNMPv3)
This vulnerability can be exploited to initiate a Denial of Service
attack on the Cisco FWSM.
Software Versions and Fixes
* CSCeb16356 (HTTP Auth)
1.1.3 and later.
* CSCeb88419 (SNMPv3)
1.1.3 and later.
The procedure to upgrade to the fixed software version is detailed at
http://www.cisco.com/en/US/products/hw/routers/ps368/products_module_configuration_guide_chapter09186a0080159caa.html#1047362.
Obtaining Fixed Software
Cisco is offering free software upgrades to address these vulnerabilities
for all affected customers.
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 the Cisco Connection Online Software Center at
http://www.cisco.com/public/sw-center/sw-usingswc.shtml.
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/tacpage/sw-center/lan/catalyst/crypto/. To
access the software download URL, you must be a registered user and you
must be logged in.
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 assistance with obtaining the software
upgrade(s).
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) using the contact information listed below. In
these cases, customers are entitled to obtain an upgrade to a later
version of the same release or as indicated by the applicable corrected
software version in the Software Versions and Fixes section (noted above).
Cisco 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
See 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.
Please have your product serial number available and give the URL of this
notice as evidence of your entitlement to a upgrade. Upgrades for
non-contract customers must be requested through the TAC.
Please do not contact either "psirt@cisco.com" or
"security-alert@cisco.com" for software upgrades.
Workarounds
* CSCeb16356 (HTTP Auth)
No workaround. Please upgrade.
* CSCeb88419 (SNMPv3)
There are two workarounds available.
* Restrict access to only allow trusted hosts on specific
interfaces to poll the SNMP server on the FWSM.
snmp-server host <if_name> <ip_addr> poll
* Disable the SNMP server on the FWSM as follows:
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
Note: The Cisco FWSM does not allow one to remove the community
string altogether. It will always be either public or a user
configured string. show snmp will still show snmp-server
community public, but this does not mean SNMP is enabled.
More details at
http://www.cisco.com/univercd/cc/td/doc/product/iaabu/pix/pix_62/cmdref/s.htm#1026423.
The Cisco PSIRT recommends that affected users upgrade to a fixed software
version of code.
Exploitation and Public Announcements
The Cisco PSIRT is not aware of any public announcements or malicious use
of the vulnerabilities described in this advisory.
Status of This Notice: Final
This is a final advisory. Although Cisco cannot guarantee the accuracy of
all statements in this advisory, all of the facts have been checked to the
best of our ability. Cisco does not anticipate issuing updated versions of
this advisory unless there is some material change in the facts. Should
there be a significant change in the facts, Cisco may update this
advisory.
A stand-alone copy or paraphrase of the text of this security advisory
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 will be posted on Cisco's worldwide website at
http://www.cisco.com/warp/public/707/cisco-sa-20031215-fwsm.shtml.
In addition to worldwide web posting, a text version of this notice is
clear-signed with the Cisco PSIRT PGP key having the fingerprint 8C82 5207
0CA9 ED40 1DD2 EE2A 7B31 A8CF 32B6 B590, and is posted to the following
e-mail and Usenet news recipients.
* cust-security-announce@cisco.com
* first-teams@first.org (includes CERT/CC)
* bugtraq@securityfocus.com
* vulnwatch@vulnwatch.org
* cisco@spot.colorado.edu
* cisco-nsp@puck.nether.net
* full-disclosure@lists.netsys.com
* comp.dcom.sys.cisco@newsgate.cisco.com
* 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.
Revision History
+------------------------------------------+
| | |Initial |
|Revision 1.0|2003-December-15|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/warp/public/707/sec_incident_response.shtml. This
includes instructions for press inquiries regarding Cisco security
notices. All Cisco security advisories are available at
http://www.cisco.com/go/psirt.
This advisory is copyright 2003 by Cisco Systems, Inc. This advisory may
be redistributed freely after the release date given at the top of the
text, provided that redistributed copies are complete and unmodified,
including all date and version information.
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