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Cisco Security Advisory: Cisco ONS15454 IP TOS Bit Vulnerability
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Revision 1.0
For Public Release 2002 June 19 at 1500 UTC
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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
Distribution
Revision History
Cisco Security Procedures
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Summary
The Cisco ONS15454 optical transport platform is vulnerable when IP
packets, with the Type Of Service (TOS) bit set, are sent to the Timing
Control Card (TCC) LAN interface. Cisco ONS software releases 3.1.0 to
3.2.0, both inclusive, are vulnerable.
This vulnerability is documented as Cisco bug ID CSCdx48853. There are
workarounds available to mitigate the effects of this vulnerability.
This advisory will be posted at
http://www.cisco.com/warp/public/707/ons-tos-vuln-pub.shtml.
Affected Products
All Cisco ONS15454 hardware running Cisco ONS release 3.1.0 to 3.2.0, both
inclusive, is affected by this vulnerability.
Hardware not affected includes the Cisco ONS15327 edge optical transport
platform, Cisco ONS15540 extended service platform, ONS15800 series,
ONS15200 series metro DWDM systems and the ONS15194 IP transport
concentrator.
No other Cisco product is currently known to be affected by this
vulnerability.
To determine your software revision, view the help-about window on the
CTC.
Details
When an IP packet with non-zero TOS bits in its header is received by the
TCC on its LAN interface, this causes software versions 3.1.0 and later to
reset the TCC. When the crafted packets are sent repeatedly, both TCCs
reset leaving no active TCC in the platform.
In order to exploit this vulnerability, an attacker must be able to
establish an IP connection to the TCC's LAN interface.
This vulnerability is documented as Cisco bug ID CSCdx48853, which
requires a CCO account to view, and can be viewed after 2002 June 20 at
1500 UTC.
Impact
When both TCCs are reset simultaneously, the E100 cards and E1000 cards
stop passing traffic. The G1000 cards traffic would not be affected. TDM
traffic may be compromised because timing is not synchronized anymore. The
protection switching feature is compromised.
Software Versions and Fixes
This vulnerability is fixed in Cisco ONS software release 3.2.1 and later.
Cisco ONS software release 3.2.1 is the maintenance release fix version
for this vulnerability. Cisco ONS software version 3.3.0 is currently
available as an interim fix release for this vulnerability until Cisco ONS
software version 3.2.1 is released at the end of July 2002.
The procedure to upgrade to the fixed software version on the Cisco ONS
15454 is detailed at:
http://www.cisco.com/univercd/cc/td/doc/product/ong/15400/r33docs/sftuprgd/index.htm.
Obtaining Fixed Software
Cisco is offering free software upgrades to address this vulnerability for
all affected customers. Customers may only install and expect support for
the feature sets they have purchased.
Customers with service contracts should contact their regular update
channels to obtain the free software upgrade identified via this advisory.
For most customers with service contracts, 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 a 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 free software
upgrade(s).
Customers who purchased directly 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 obtain fixed software 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: tacat_private
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
advisory as evidence of your entitlement to a free upgrade.
Please do not contact either "psirtat_private" or
"security-alertat_private" for software upgrades.
Workarounds
Restrict IP traffic to the gateway node(s) with a router configured to
change the TOS to zero for all out-bound packets going to the TCC.
Sample Cisco router configuration:
class-map match-all MY_LAN
match any !--- Matches all packets
!
!
policy-map SET_TOS
class MY_LAN
set ip dscp default
!--- Sets all packets to "00000000" (Best effort)
!
interface FastEthernet0/0
service-policy output SET_TOS
!--- Modifies outbound packets
Exploitation and Public Announcements
This defect was reported by a Cisco customer. The Cisco PSIRT is not aware
of any public announcements or malicious use of the vulnerability
described in this advisory.
Status of This Advisory: 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/ons-tos-vuln-pub.shtml.
In addition to worldwide website posting, a text version of this advisory
is clear-signed with the Cisco PSIRT PGP keyID 0x1A88BFC5 with fingerprint
17E6 4AC4 4DD5 F889 1560 919D 3FC6 EA52 1A88 BFC5 and is posted to the
following e-mail and Usenet news recipients:
* cust-security-announceat_private
* bugtraqat_private
* firewallsat_private
* first-teamsat_private (includes CERT/CC)
* ciscoat_private
* cisco-nspat_private
* comp.dcom.sys.cisco
* 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
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| Revision 1.0 | 2002-Jun-19 | Initial public release. |
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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/go/psirt. This includes instructions for
press inquiries regarding Cisco security advisories.
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This advisory is copyright 2002 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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