FYI. Mark.
---------- Forwarded Message ----------
Subject: [c-nsp] Cisco Security Advisory: Vulnerability in
Cisco IOS with OSPF, MPLS VPN, and Supervisor 32,
Supervisor 720, or Route Switch Processor 720
Date: Thursday 27 March 2008
From: Cisco Systems Product Security Incident Response Team
<[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Cisco Security Advisory: Vulnerability in Cisco IOS with
OSPF, MPLS
VPN, and Supervisor 32, Supervisor
720, or
Route Switch Processor 720
Advisory ID: cisco-sa-20080326-queue
http://www.cisco.com/warp/public/707/cisco-sa-20080326-queue.shtml
Revision 1.0
For Public Release 2008 March 26 1600 UTC (GMT)
Summary
=======
Certain Cisco Catalyst 6500 Series and Cisco 7600 Router
devices that
run branches of Cisco IOS based on 12.2 can be vulnerable to
a denial
of service vulnerability that can prevent any traffic from
entering
an affected interface. For a device to be vulnerable, it
must be
configured for Open Shortest Path First (OSPF) Sham-Link and
Multi
Protocol Label Switching (MPLS) Virtual Private Networking
(VPN).
This vulnerability only affects Cisco Catalyst 6500 Series
or
Catalyst 7600 Series devices with the Supervisor Engine 32
(Sup32),
Supervisor Engine 720 (Sup720) or Route Switch Processor 720
(RSP720)
modules. The Supervisor 32, Supervisor 720, Supervisor
720-3B,
Supervisor 720-3BXL, Route Switch Processor 720, Route
Switch
Processor 720-3C, and Route Switch Processor 720-3CXL are
all
potentially vulnerable.
The OSPF and MPLS VPNs are not enabled by default.
This advisory is posted at
http://www.cisco.com/warp/public/707/cisco-sa-20080326-queue.shtml
Note: The March 26, 2008 publication includes five Security
Advisories. The Advisories all affect Cisco IOS. Each
Advisory lists
the releases that correct the vulnerability described in the
Advisory, and the Advisories also detail the releases that
correct
the vulnerabilities in all five Advisories. Please reference
the
following software table to find a release which fixes all
published
Security Advisories as of March 26th, 2008.
* March 26th bundled IOS Advisory Table
http://www.cisco.com/warp/public/707/cisco-sa-20080326-bundle.shtml
Individual publication links are listed below:
* Cisco IOS Virtual Private Dial-up Network Denial of
Service
Vulnerability
http://www.cisco.com/warp/public/707/cisco-sa-20080326-pptp.shtml
* Multiple DLSw Denial of Service Vulnerabilities in Cisco
IOS
http://www.cisco.com/warp/public/707/cisco-sa-20080326-dlsw.shtml
* Cisco IOS User Datagram Protocol Delivery Issue For
IPv4/IPv6
Dual-stack Routers
http://www.cisco.com/warp/public/707/cisco-sa-20080326-IPv4IPv6.shtml
* Vulnerability in Cisco IOS with OSPF, MPLS VPN, and
Supervisor
32, Supervisor 720, or Route Switch Processor 720
http://www.cisco.com/warp/public/707/cisco-sa-20080326-queue.shtml
* Cisco IOS Multicast Virtual Private Network (MVPN) Data
Leak
http://www.cisco.com/warp/public/707/cisco-sa-20080326-mvpn.shtml
Affected Products
================
Vulnerable Products
+------------------
All Cisco products based on the Supervisor Engine 32
(Sup32),
Supervisor Engine 720 (Sup720) or Route Switch Processor 720
(RSP720)
are potentially vulnerable. Cisco Sup720 and RSP720 products
have
support for daughter cards that enhance their functionality.
These
daughter cards attach directly to the Sup720 or RSP720 and
have names
like PFC-3B, PFC-3BXL, PFC-3C, and PFC-3CXL. The product
number of
the Sup720 or RSP720 can change to reflect the daughter card
that is
installed, such as RSP720-3CXL.
Because the vulnerability affects the Sup720 and RSP720, all
versions
of the Sup720 or RSP720 are vulnerable, regardless of the
daughter
card that is installed.
* Cisco Catalyst 6500 Series devices with the Sup32,
Sup720,
Sup720-3B, or Sup720-3BXL
* Cisco 7600 Series devices with the Sup32, Sup720,
Sup720-3B, or
Sup720-3BXL
* Cisco 7600 Series devices with the RSP720, RSP720-3C, or
RSP720-3CXL
* Cisco ME 6524 Ethernet Switch
Products Confirmed Not Vulnerable
+--------------------------------
No other Cisco products are currently known to be affected
by this
vulnerability.
Cisco Bug ID CSCsf12082 was integrated into additional IOS
releases
that do not run on the vulnerable hardware, but only the
platforms
mentioned in the Vulnerable Products section above are
affected by
this vulnerability.
Details
=======
Vulnerable Cisco devices, when configured for Multi Protocol
Label
Switching (MPLS) Virtual Private Networking (VPN) and Open
Shortest
Path First (OSPF) sham-link, can suffer from a blocked
queue,
memory leak and/or restart of the device
This vulnerability is documented in Cisco bug ID CSCsf12082,
and has
been assigned CVE ID CVE-2008-0057.
The following combination of hardware and software
configuration must
be present for the device to be vulnerable:
* Cisco Catalyst Sup32, Sup720, or RSP720 is present
* MPLS VPN is configured
* OSPF sham-link is configured
In order to determine whether you are running this feature,
use the
show running-config command and search for the
address-family vpnv4
and area sham-link router configuration commands. The
following
command displays all configuration lines that meet the
following
criteria:
* Begins with the word "router," OR
* Includes "address-family vpnv4," OR
* Includes "sham-link"
Router# show run | include ^router |address-family
vpnv4|sham-link
router bgp 1
address-family vpnv4
router ospf 1 vrf VRFNAME
area 0 sham-link 192.168.1.1 192.168.100.1
Router#
For customers that run versions of IOS that support the
section
modifier, an additional option is available to view the
relevant
sections of the running configuration:
Router# show run | section ^router
router bgp 1
[snip]
address-family vpnv4
router ospf 1 vrf VRFNAME
area 0 sham-link 192.168.1.1 192.168.100.1
[snip]
If certain packets are received by a device that meets the
above
requirements, the input queue of the interface that receives
these
packets can become blocked, which can prohibit additional
traffic
from entering the interface and cause a denial of service
condition.
In addition to a potential blocked interface queue, the
device can
also suffer a memory leak or restart. In the event of a
memory leak,
the device is unable to forward traffic once available
memory is
depleted.
For more information on MPLS VPNs, please reference the
following
document:
http://www.cisco.com/en/US/docs/net_mgmt/vpn_solutions_center/1.1/user/guide/VPN_UG1.html
For more information on OSPF sham-links, please reference
the
following document:
http://www.cisco.com/en/US/docs/ios/12_2t/12_2t8/feature/guide/ospfshmk.html
Identifying a Memory Leak
+------------------------
This vulnerability can manifest as a leak in the I/O memory
pool. The
following is an example of a system message that indicates
an
exhaustion of the I/O pool:
006029: Aug 10: %SYS-2-MALLOCFAIL: Memory allocation of
808 bytes failed from 0x41613238, alignment 32
Pool: I/O Free: 176 Cause: Not enough free memory
Alternate Pool: None Free: 0 Cause: No Alternate pool
Note that in the above output, the affected memory pool is
Pool: I/O,
and the cause is Cause: Not enough free memory. This output
indicates
that the I/O memory pool has been exhausted.
Additionally, a user with enable-level access can check the
device
through the show buffers command to identify buffer
allocation
failures.
Router#show buffers
Buffer elements:
496 in free list (500 max allowed)
77298300 hits, 0 misses, 0 created
Public buffer pools:
Small buffers, 104 bytes (total 148654, permanent 1024,
peak 148654 @ 1d12h):
0 in free list (128 min, 2048 max allowed)
24688031 hits, 4023203 misses, 0 trims, 147630 created
3243434 failures (3182828 no memory)
The above output shows that buffer allocation failed due to
insufficient memory.
Identifying a Blocked Interface
+------------------------------
A symptom of this type of blocked queue is the failure of
control-plane protocols such as routing protocols (OSPF,
Enhanced
Interior Gateway Routing Protocol (EIGRP), Border Gateway
Protocol
(BGP), Intermediate System to Intermediate System (ISIS),
etc.) and
MPLS TDP/LDP to properly establish connections over an
affected
interface.
In order to identify a blocked input interface, issue the
show
interfaces command, and search for the Input Queue line. The
size of
the input queue can continue to increase. If the current
size, which
is 76 in the example below, is larger than the maximum size
(75), the
input queue is blocked.
It is possible that a device receives a high rate of traffic
destined
to the control plane, and the full queue is only a transient
event.
In order to verify if the interface is actually blocked,
shut down
the interface with the shutdown interface configuration
command and
examine the input queue. If the input queue does not display
0
packets, the interface is blocked.
Router#show interface ethernet 0/0
Ethernet0/0 is up, line protocol is up
Hardware is AmdP2, address is 0050.500e.f1e0 (bia
0050.500e.f1e0)
Internet address is 172.16.1.9/24
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, rely
255/255, load 1/255
Encapsulation ARPA, loopback not set, keepalive set
(10 sec)
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:41, output 00:00:07, output hang
never
Last clearing of "show interface" counters 00:07:18
Input queue: 76/75/1091/0 (size/max/drops/flushes);
Total output drops: 0
!--- The 76/75 shows that this is blocked
Vulnerability Scoring Details
=============================
Cisco has provided scores for the vulnerabilities in this
advisory
based on the Common Vulnerability Scoring System (CVSS). The
CVSS
scoring in this Security Advisory is done in accordance with
CVSS
Version 2.0.
CVSS is a standards-based scoring method that conveys
vulnerability
severity and helps determine urgency and priority of
response.
Cisco has provided a base and temporal score. Customers can
then
compute environmental scores to assist in determining the
impact of
the vulnerability in individual networks.
Cisco has provided an FAQ to answer additional questions
regarding
CVSS at
http://www.cisco.com/web/about/security/intelligence/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/cvss
CSCsf12082 - SUP720 facing small buffer leak and crashes
CVSS Base Score - 7.8
Access Vector: Network
Access Complexity: Low
Authentication: None
Confidentiality Impact: None
Integrity Impact: None
Availability Impact: Complete
CVSS Temporal Score - 6.1
Exploitability: Proof-of-Concept
Remediation Level: Official-Fix
Report Confidence: Confirmed
Impact
======
Exploitation of this vulnerability may result in a blocked
interface
input queue, memory leak, and/or restart of the device.
Repeated
exploitation of this vulnerability may result in an extended
denial
of service.
Software Versions 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.
Each row of the Cisco IOS software table (below) names a
Cisco IOS
release train. If a given release train is vulnerable, then
the
earliest possible releases that contain the fix (along with
the
anticipated date of availability for each, if applicable)
are listed
in the "First Fixed Release" column of the table.
The "Recommended
Release" column indicates the releases which have fixes for
all the
published vulnerabilities at the time of this Advisory. A
device
running a release in the given train that is earlier than
the release
in a specific column (less than the First Fixed Release) is
known to
be vulnerable. Cisco recommends upgrading to a release equal
to or
later than the release in the "Recommended Releases" column
of the
table.
+----------------------------------------+
| Major | Availability of Repaired |
| Release | Releases |
|------------+---------------------------|
| Affected | First Fixed | Recommended |
| 12.0-Based | Release | Release |
| Releases | | |
|----------------------------------------|
| There are no affected 12.0 based |
| releases |
|----------------------------------------|
| Affected | First Fixed | Recommended |
| 12.1-Based | Release | Release |
| Releases | | |
|----------------------------------------|
| There are no affected 12.1 based |
| releases |
|----------------------------------------|
| Affected | First Fixed | Recommended |
| 12.2-Based | Release | Release |
| Releases | | |
|------------+-------------+-------------|
| 12.2 | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2B | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2BC | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2BW | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2BY | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2BZ | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2CX | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2CY | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2CZ | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2DA | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2DD | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2DX | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2EU | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2EW | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2EWA | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2EX | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2EY | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2EZ | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2FX | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2FY | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2FZ | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2IXA | Vulnerable; | |
| | contact TAC | |
|------------+-------------+-------------|
| 12.2IXB | Vulnerable; | |
| | contact TAC | |
|------------+-------------+-------------|
| 12.2IXC | Vulnerable; | |
| | contact TAC | |
|------------+-------------+-------------|
| 12.2IXD | Vulnerable; | |
| | contact TAC | |
|------------+-------------+-------------|
| | Vulnerable; | 12.2(18) |
| | migrate to | IXF; |
| 12.2IXE | any release | Available |
| | in 12.2IXF | on |
| | | 31-MAR-2008 |
|------------+-------------+-------------|
| 12.2JA | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2JK | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2MB | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2MC | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2S | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SB | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SBC | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SCA | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SE | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SEA | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SEB | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SEC | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SED | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SEE | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SEF | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SEG | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SG | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SGA | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SL | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SM | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SO | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SRA | 12.2(33) | 12.2(33) |
| | SRA4 | SRA7 |
|------------+-------------+-------------|
| 12.2SRB | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SRC | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SU | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SV | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SVA | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SVC | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SVD | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SW | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SX | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| | Vulnerable; | 12.2(18) |
| 12.2SXA | first fixed | SXF13 |
| | in 12.2SXF | |
|------------+-------------+-------------|
| | Vulnerable; | 12.2(18) |
| 12.2SXB | first fixed | SXF13 |
| | in 12.2SXF | |
|------------+-------------+-------------|
| | Vulnerable; | 12.2(18) |
| 12.2SXD | first fixed | SXF13 |
| | in 12.2SXF | |
|------------+-------------+-------------|
| | Vulnerable; | 12.2(18) |
| 12.2SXE | first fixed | SXF13 |
| | in 12.2SXF | |
|------------+-------------+-------------|
| 12.2SXF | 12.2(18) | 12.2(18) |
| | SXF6 | SXF13 |
|------------+-------------+-------------|
| 12.2SXH | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SY | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2SZ | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2T | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2TPC | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2UZ | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XA | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XB | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XC | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XD | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XE | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XF | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XG | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XH | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XI | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XJ | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XK | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XL | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XM | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XN | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XO | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XQ | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XR | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XS | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XT | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XU | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XV | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2XW | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YA | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YB | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YC | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YD | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YE | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YF | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YG | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YH | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YJ | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YK | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YL | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YM | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YN | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YO | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YP | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YQ | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YR | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YS | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YT | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YU | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YV | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YW | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YX | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YY | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2YZ | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2ZA | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2ZB | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2ZC | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2ZD | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2ZE | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2ZF | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2ZG | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2ZH | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2ZJ | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2ZL | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| 12.2ZP | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| | Vulnerable; | |
| 12.2ZU | migrate to | 12.2(33) |
| | any release | SXH2 |
| | in 12.2SXH | |
|------------+-------------+-------------|
| 12.2ZY | Not | |
| | Vulnerable | |
|------------+-------------+-------------|
| Affected | First Fixed | Recommended |
| 12.3-Based | Release | Release |
| Releases | | |
|----------------------------------------|
| There are no affected 12.3 based |
| releases |
|----------------------------------------|
| Affected | First Fixed | Recommended |
| 12.4-Based | Release | Release |
| Releases | | |
|----------------------------------------|
| There are no affected 12.4 based |
| releases |
+----------------------------------------+
Workarounds
===========
Once a device interface queue has been exhausted, only a
device
restart can clear OSPF packets in the blocked queue.
Due to the manner in which these packets are processed, the
queue
block occurs prior to the OSPF MD5 check. The OSPF MD5
configuration
does not protect a device from this vulnerability.
Increasing the Selective Packet Discard (SPD) Headroom
+-----------------------------------------------------
At the most basic level, the Selective Packet Discard (SPD)
provides
extended buffering for control plane traffic. Known as the
SPD
headroom, this additional queue depth is typically reserved
for
traffic with IP Precedence equal to 6 (such as BGP), the
Connectionless Network Service (CLNS) based routing protocol
Intermediate System-to-Intermediate System (IS-IS), OSPF,
and Layer 2
keepalives.
Increasing the SPD headroom provides additional buffering
for OSPF
packets. In the event of a blocked queue, the SPD headroom
can be
increased to allow more control plane traffic buffer space.
More information on SPD can be found in the following white
paper:
http://www.cisco.com/web/about/security/intelligence/spd.html
It is possible to expand the queue size to accommodate more
packets,
but packets can still accumulate until the expanded queue is
exhausted. As a temporary workaround that allows traffic to
continue
to flow, the input hold queue can be increased. Any
additional
malformed packets still fill the queue, but increasing the
input
queue depth can extend the amount of time before the input
queue
fills and traffic ceases flowing. The following example
demonstrates
how to set the input queue size from the default of 75 to
the maximum
of 4096:
Router# configure terminal
Router(configure)# interface FastEthernet 0/0
Router(config-if)# hold-queue 4096 in
Removing OSPF Sham-Link Configuration
+------------------------------------
Because OSPF Sham-Link configuration is required for the
vulnerability to be present, removing Sham-Link
functionality
eliminates exposure to this vulnerability. In order to
remove the
OSPF Sham-Link configuration from a device, the OSPF
configuration
must be changed on each interface where Sham-Link is
configured.
For configuration information on OSPF Sham-Link, please
consult the
following document:
http://www.cisco.com/en/US/docs/ios/12_2t/12_2t8/feature/guide/ospfshmk.html
Cisco IOS Embedded Event Manager
+-------------------------------
Cisco IOS Embedded Event Manager (EEM) provides event
detection and
reaction capabilities on a Cisco IOS device. It is possible
to detect
blocked interface queues with an EEM policy. EEM can alert
administrators of blocked interfaces with email, a syslog
message, or
a Simple Network Management Protocol (SNMP) trap.
A sample EEM policy that uses syslog to alert administrators
of
blocked interfaces is available at Cisco Beyond, an online
community
dedicated to EEM. A sample script is available at the
following link:
http://forums.cisco.com/eforum/servlet/EEM?page=eem&fn=script&scriptId=981
More information about EEM is available from Cisco.com at
the
following link:
http://www.cisco.com/en/US/products/ps6815/products_ios_protocol_group_home.html
Obtaining Fixed Software
========================
Cisco has released free software updates that address this
vulnerability. 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/products/prod_warranties_item09186a008088e31f.html
or as otherwise set forth at Cisco.com Downloads at
http://www.cisco.com/public/sw-center/sw-usingswc.shtml.
Do not contact [EMAIL PROTECTED] or [EMAIL PROTECTED]
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 agreements 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 do not hold a
Cisco
service contract, and customers who purchase through
third-party
vendors but are unsuccessful in obtaining fixed software
through
their point of sale should acquire 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: [EMAIL PROTECTED]
Customers should have their product serial number available
and be
prepared to give the URL of this notice as evidence of
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 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.
This vulnerability was reported to Cisco by a customer.
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-20080326-queue.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.
* [EMAIL PROTECTED]
* [EMAIL PROTECTED]
* [EMAIL PROTECTED]
* [EMAIL PROTECTED]
* [EMAIL PROTECTED]
* [EMAIL PROTECTED]
* [EMAIL PROTECTED]
* [EMAIL PROTECTED]
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 | 2008-March-26 | 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/products/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/go/psirt.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.8 (Darwin)
iEYEARECAAYFAkfqb/IACgkQ86n/Gc8U/uDSVQCcD/eTXkZUyMzZERQXt+d9DhGD
dKgAnjQ+Gsmkh4/x1l5K8q2E9QKUJN1d
=xTuf
-----END PGP SIGNATURE-----
_______________________________________________
cisco-nsp mailing list [EMAIL PROTECTED]
https://puck.nether.net/mailman/listinfo/cisco-nsp
archive at http://puck.nether.net/pipermail/cisco-nsp/
-------------------------------------------------------
signature.asc
Description: This is a digitally signed message part.
_______________________________________________ LUG mailing list [email protected] http://kym.net/mailman/listinfo/lug %LUG is generously hosted by INFOCOM http://www.infocom.co.ug/ The above comments and data are owned by whoever posted them (including attachments if any). The List's Host is not responsible for them in any way. ---------------------------------------
