O-039: CISCO FWSM Vulnerabilities

[***** Start CISCO Security Advisory ID #47288 *****]


Cisco Security Advisory: Cisco FWSM Vulnerabilities
Document ID: 47288
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  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   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 
Revision 1.0
 2003-December-15
 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/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.

[***** End CISCO Security Advisory ID #47288 *****]

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