A vulnerability exists in the Cisco Firewall Services Module (FWSM) for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers that may cause the Cisco FWSM to reload after processing a malformed Skinny Client Control Protocol (SCCP) message. Devices are affected when SCCP inspection is enabled. Cisco has released software updates that address this vulnerability. This advisory is posted at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110223-fwsm. Note: Cisco ASA 5500 Series Adaptive Security Appliances are affected by the vulnerability described in this advisory. A separate Cisco Security Advisory has been published to disclose this and other vulnerabilities that affect the Cisco ASA 5500 Series Adaptive Security Appliances. The advisory is available at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110223-asa.
A vulnerability exists in the Cisco Firewall Services Module (FWSM) for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers that may cause the Cisco FWSM to reload after processing a malformed Skinny Client Control Protocol (SCCP) message. Devices are affected when SCCP inspection is enabled.
Cisco has released software updates that address this vulnerability.
This advisory is posted at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110223-fwsm.
Note: Cisco ASA 5500 Series Adaptive Security Appliances are affected by the vulnerability described in this advisory. A separate Cisco Security Advisory has been published to disclose this and other vulnerabilities that affect the Cisco ASA 5500 Series Adaptive Security Appliances. The advisory is available at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110223-asa.
Versions 3.1.x, 3.2.x, 4.0.x, and 4.1.x of Cisco FWSM software are affected by this vulnerability if SCCP inspection is enabled. SCCP inspection is enabled by default.
To determine whether SCCP inspection is enabled, issue the show service-policy | include skinny command and confirm that the command returns output. Example output follows:
Vulmon
fwsm#show service-policy | include skinny
Inspect: skinny , packet 0, drop 0, reset-drop 0
Alternatively, a device that has SCCP inspection enabled has a configuration similar to the following:
class-map inspection_default match default-inspection-traffic ! policy-map global_policy class inspection_default ... inspect skinny ... ! service-policy global_policy global
Note: The service policy could also be applied to a specific interface. (Global application is shown in the previous example.)
To determine the version of Cisco FWSM software that is running, issue the show module command from Cisco IOS Software or Cisco Catalyst Operating System Software to identify what modules and submodules are installed on the system.
The following example shows a system with a Cisco FWSM (WS-SVC-FWM-1) installed in slot 2:
switch>show module Mod Ports Card Type Model Serial No. --- ----- -------------------------------------- ------------------ ----------- 1 16 SFM-capable 16 port 1000mb GBIC WS-X6516-GBIC SAL06334NS9 2 6 Firewall Module WS-SVC-FWM-1 SAD10360485 3 8 Intrusion Detection System WS-SVC-IDSM-2 SAD0932089Z 4 4 SLB Application Processor Complex WS-X6066-SLB-APC SAD093004BD 5 2 Supervisor Engine 720 (Active) WS-SUP720-3B SAL0934888E Mod MAC addresses Hw Fw Sw Status --- ---------------------------------- ------ ------------ ------------ ------- 1 0009.11e3.ade8 to 0009.11e3.adf7 5.1 6.3(1) 8.5(0.46)RFW Ok 2 0018.ba41.5092 to 0018.ba41.5099 4.0 7.2(1) 3.2(2)10 Ok 3 0014.a90c.9956 to 0014.a90c.995d 5.0 7.2(1) 5.1(6)E1 Ok 4 0014.a90c.66e6 to 0014.a90c.66ed 1.7 4.2(3) Ok 5 0013.c42e.7fe0 to 0013.c42e.7fe3 4.4 8.1(3) 12.2(18)SXF1 Ok [...]
After locating the correct slot, issue the show module
switch>show module 2 Mod Ports Card Type Model Serial No. --- ----- -------------------------------------- ------------------ ----------- 2 6 Firewall Module WS-SVC-FWM-1 SAD10360485 Mod MAC addresses Hw Fw Sw Status --- ---------------------------------- ------ ------------ ------------ ------- 2 0018.ba41.5092 to 0018.ba41.5099 4.0 7.2(1) 3.2(2)10 Ok [...]
The preceding example shows that the FWSM is running software version 3.2(2)10 as indicated by the Sw column.
Note: Recent versions of Cisco IOS Software will show the software version
of each module in the output from the show module
command; therefore, executing the show module
If a Virtual Switching System (VSS) is used to allow two physical Cisco
Catalyst 6500 Series Switches to operate as a single logical virtual switch,
the show module switch all command can display the
software version of all FWSMs that belong to switch 1 and switch 2. The output
from this command will be similar to the output from show module
Alternatively, version information can be obtained directly from the FWSM through the show version command, as shown in the following example:
FWSM> show version FWSM Firewall Version 3.2(2)10 [...]
Customers who use the Cisco Adaptive Security Device Manager (ASDM) to manage their devices can find the version of the software displayed in the table in the login window or in the upper left corner of the ASDM window. The version notation is similar to the following example:
FWSM Version: 3.2(2)10
With the exception of Cisco ASA 5500 Series Adaptive Security Appliances, no other Cisco products are currently known to be affected by this vulnerability.
The Cisco FWSM is a high-speed, integrated firewall module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers. The FWSM offers firewall services with stateful packet filtering and deep packet inspection.
The Cisco FWSM is affected by a vulnerability that may cause the device to reload during the processing of a malformed SCCP message when SCCP inspection is enabled.
This vulnerability is triggered only by transit traffic; traffic that is destined to the device does not trigger this vulnerability.
This vulnerability is documented in Cisco bug ID CSCtl84952 ( registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2011-0394.
If SCCP inspection is not required, it can be disabled so the device is no longer affected by the vulnerability. Administrators can disable SCCP inspection by issuing the no inspect skinny command in class configuration submode in the policy map configuration. If SCCP inspection is required, there are no workarounds.
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 following Cisco FWSM software table describes a major Cisco FWSM software train and the earliest possible release in that train that contains the fix (the "First Fixed Release") and the anticipated date of availability (if not currently available) in the First Fixed Release column. A device that is running a release that is earlier than the release in a specific column (earlier than the First Fixed Release) is known to be vulnerable. The release should be upgraded at least to the indicated release or a later version (later than or equal to the First Fixed Release label).
|
Major Release |
First Fixed Release |
|---|---|
|
3.1 |
3.1(20) |
|
3.2 |
3.2(20) |
|
4.0 |
4.0(15) |
|
4.1 |
4.1(5) |
Fixed Cisco FWSM software can be downloaded from the Software Center on Cisco.com by visiting http://www.cisco.com/cisco/software/navigator.html ( registered customers only) and navigating to Products > Security > Firewall > Firewall Integrated Switch/Router Services > Cisco Catalyst 6500 Series Firewall Services Module > Firewall Services Module (FWSM) Software.
The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory.
This vulnerability was found during internal testing.
To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
|
Revision 1.0 |
2011-February-23 |
Initial public release. |
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