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A denial of service (DoS) vulnerability exists in the Cisco Content Services Gateway - Second Generation, that runs on the Cisco Service and Application Module for IP (SAMI). An unauthenticated, remote attacker could exploit this vulnerability by sending a series of crafted ICMP packets to an affected device. Exploitation could cause the device to reload.
There are no workarounds available to mitigate exploitation of this vulnerability other than blocking ICMP traffic destined to the affected device.
This advisory is posted at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110706-csg.
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Vulnerable Products
All versions of the Cisco IOS Software for the Content Services Gateway: Second Generation prior to the first fixed release are affected, as indicated in the "Software Versions and Fixes" section of this advisory.
Determining Cisco CSG Software Versions
To determine the version of Cisco IOS Software that is running on the Cisco CSG2, issue the "show module" command from Cisco IOS Software on the switch on which the Cisco CSG2 module is installed to identify what modules and sub-modules are installed on the system.
Cisco Content Services Gateway: Second Generation runs on the Cisco Service and Application Module for IP (SAMI) card, and is identified in the following example in slot 2 via the WS-SVC-SAMI-BB-K9 identification:
C7600#show module Mod Ports Card Type Model Serial No. --- ----- -------------------------------------- ------------------ ----------- 1 2 Supervisor Engine 720 (Active) WS-SUP720-3BXL JAF1226ARQS 2 1 SAMI Module (csgk9) WS-SVC-SAMI-BB-K9 SAD113906P1 4 48 CEF720 48 port 10/100/1000mb Ethernet WS-X6748-GE-TX SAL1127T6XY Mod MAC addresses Hw Fw Sw Status --- ---------------------------------- ------ ------------ ------------ ------- 1 001e.be6e.a018 to 001e.be6e.a01b 5.6 8.5(2) 12.2(33)SRC5 Ok 2 001d.45f8.f3dc to 001d.45f8.f3e3 2.1 8.7(0.22)FW1 12.4(2010040 Ok 4 001c.587a.ef20 to 001c.587a.ef4f 2.6 12.2(14r)S5 12.2(33)SRC5 Ok Mod Sub-Module Model Serial Hw Status ---- --------------------------- ------------------ ----------- ------- ------- 1 Policy Feature Card 3 WS-F6K-PFC3BXL JAF1226BNQM 1.8 Ok 1 MSFC3 Daughterboard WS-SUP720 JAF1226BNMC 3.1 Ok 2 SAMI Daughterboard 1 SAMI-DC-BB SAD114400L9 1.1 Other 2 SAMI Daughterboard 2 SAMI-DC-BB SAD114207FU 1.1 Other 4 Centralized Forwarding Card WS-F6700-CFC SAL1029VGFK 2.0 Ok Mod Online Diag Status ---- ------------------- 1 Pass 2 Pass 4 Pass C7600#
After locating the correct slot, issue the "session slot <module number> processor <3-9>" command to open a console connection to the respective Cisco Content Services Gateway: Second Generation. For example: session slot 2 processor 3. The number 3 is the control processor (CP) number for the CSG2. Always session into CP 3 when configuring or monitoring the Cisco Content Services Gateway: Second Generation. Once connected to the Cisco Content Services Gateway: Second Generation, perform the "show version" command:
The following example shows that the Cisco Content Services Gateway: Second Generation is running software Release 12.4(24)MD1:
CSG2#show version Cisco IOS Software, SAMI Software (SAMI-CSGK9-M), Version 12.4(24)MD1, RELEASE SOFTWARE (fc2) Technical Support: http://www.cisco.com/techsupport Copyright (c) 1986-2010 by Cisco Systems, Inc. Compiled Wed 07-Apr-10 09:50 by prod_rel_team --- output truncated ---
Products Confirmed Not Vulnerable
Content Services Gateway: First Generation is not affected by this vulnerability.
Note: Other SAMI-based applications are not affected. The Cisco Gateway GPRS Support Node (GGSN), the Cisco Mobile Wireless Home Agent (HA), the Cisco Wireless Security Gateway (WSG), the Cisco Broadband Wireless Gateway and Cisco IP Transfer Point (ITP), and the Cisco Long Term Evolution (LTE) Gateway are not affected.
The Cisco 7600 Series Router is not affected by this vulnerability, only the Cisco CSG (2nd generation) module is affected.
No other Cisco products are currently known to be affected by this vulnerability.
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The Cisco Content Services Gateway: Second Generation provides intelligent network capabilities such as flexible policy management and billing based on deep-packet inspection, as well as subscriber and application awareness capabilities that enable mobile operators to quickly and easily offer value-added, differentiated services over their mobile data networks.
A DoS vulnerability exists in the Cisco Content Services Gateway: Second Generation could allow an unauthenticated attacker to cause a device reload by sending crafted ICMP messages to the affected device.
Note: The Cisco Gateway GPRS Support Node (GGSN), the Cisco Mobile Wireless Home Agent (HA), the Cisco Wireless Security Gateway (WSG), the Cisco Broadband Wireless Gateway and Cisco IP Transfer Point (ITP), and the Cisco Long Term Evolution (LTE) Gateway are not affected.
This vulnerability is documented in Cisco bug ID CSCtl79577 ( registered customers only) and has been assigned CVE ID CVE-2011-2064.
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There are no available workarounds to mitigate this vulnerability other than applying infrastructure access control lists (iACLs) on the Cisco 7600 router to block ICMP traffic destined to the IP address of the Cisco CSG. Administrators can construct an iACL by explicitly permitting only authorized traffic to enter the network at ingress access points or permitting authorized traffic to transit the network in accordance with existing security policies and configurations. An iACL workaround cannot provide complete protection against these vulnerabilities when the attack originates from a trusted source address.
The iACL policy denies unauthorized ICMP packet types, including echo request, echo-reply, host-unreachable, traceroute, packet-too-big, time-exceeded, and unreachable, that are sent to affected devices. In the following example, 192.168.60.0/24 is the IP address space that is used by the affected devices, and the host at 192.168.100.1 is considered a trusted source that requires access to the affected devices. Care should be taken to allow required traffic for routing and administrative access prior to denying all unauthorized traffic. Whenever possible, infrastructure address space should be distinct from the address space used for user and services segments. Using this addressing methodology will assist with the construction and deployment of iACLs.
Additional information about iACLs is in Protecting Your Core: Infrastructure Protection Access Control Lists.
ip access-list extended Infrastructure-ACL-Policy ! !-- Include explicit permit statements for trusted sources !-- that require access on the vulnerable protocol ! permit icmp host 192.168.100.1 192.168.60.0 0.0.0.255 echo permit icmp host 192.168.100.1 192.168.60.0 0.0.0.255 echo-reply permit icmp host 192.168.100.1 192.168.60.0 0.0.0.255 host-unreachable permit icmp host 192.168.100.1 192.168.60.0 0.0.0.255 traceroute permit icmp host 192.168.100.1 192.168.60.0 0.0.0.255 packet-too-big permit icmp host 192.168.100.1 192.168.60.0 0.0.0.255 time-exceeded permit icmp host 192.168.100.1 192.168.60.0 0.0.0.255 unreachable ! !-- The following vulnerability-specific access control entries !-- (ACEs) can aid in identification of attacks ! deny icmp any 192.168.60.0 0.0.0.255 echo deny icmp any 192.168.60.0 0.0.0.255 echo-reply deny icmp any 192.168.60.0 0.0.0.255 host-unreachable deny icmp any 192.168.60.0 0.0.0.255 traceroute deny icmp any 192.168.60.0 0.0.0.255 packet-too-big deny icmp any 192.168.60.0 0.0.0.255 time-exceeded deny icmp any 192.168.60.0 0.0.0.255 unreachable ! !-- Explicit deny ACE for traffic sent to addresses configured within !-- the infrastructure address space ! deny ip any 192.168.60.0 0.0.0.255 ! !-- Permit or deny all other Layer 3 and Layer 4 traffic in accordance !-- with existing security policies and configurations ! !-- Apply iACL to interfaces in the ingress direction ! interface GigabitEthernet0/0 ip access-group Infrastructure-ACL-Policy in
Additional mitigations that can be deployed on Cisco devices within the network are available in the Cisco Applied Mitigation Bulletin companion document for this advisory, which is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoAppliedMitigationBulletin/cisco-amb-20110706-csg
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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 vulnerability 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 Release
Availability of Repaired Releases
Affected 12.x-Based Releases
First Fixed Release
12.0 - 12.3
12.0 through 12.3 based releases are not affected
Affected 12.4-Based Releases
First Fixed Release
12.4MD
Not vulnerable
12.4MDA
All 12.4MDA releases prior to 12.4(24)MDA5 are affected. First fixed in 12.4(24)MDA5
12.4MDB
Not vulnerable
Affected 15.X-Based Releases
First Fixed Release
15.0 - 15.1
15.0 through 15.1 based releases are not affected
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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.
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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.
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Revision 1.0
2011-July-06
Initial public release.
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