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Cisco Applied Mitigation Bulletin

Identifying and Mitigating Exploitation of the Cisco Unified Communications Manager and Cisco IOS Software Session Initiation Protocol Denial of Service Vulnerability

 
Threat Type:IntelliShield: Applied Mitigation Bulletin
IntelliShield ID:26765
Version:1
First Published:2012 September 26 16:13 GMT
Last Published:2012 September 26 16:13 GMT
Port: 5060, 5061
CVE:CVE-2012-3949
Urgency:Probable Use
Credibility:Confirmed
Severity:Mild Damage
 
Version Summary:Cisco Applied Mitigation Bulletin initial public release.
 

Cisco Response

This Applied Mitigation Bulletin is a companion document to the following PSIRT Security Advisories:

  • Advisory ID: cisco-sa-20120926-sip
  • Advisory ID: cisco-sa-20120926-cucm

This document provides identification and mitigation techniques that administrators can deploy on Cisco network devices.

Vulnerability Characteristics

There is a vulnerability in Cisco products that process the Session Initiation Protocol (SIP). The following subsections summarize the vulnerability:

Vulnerability in the Cisco Unified Communications Manager Session Initiation Protocol (SIP) implementation: This vulnerability can be exploited remotely without authentication and without end-user interaction. Successful exploitation of this vulnerability could cause a denial of service (DoS) condition. Repeated attempts to exploit this vulnerability could result in a sustained DoS condition. The attack vectors for exploitation are through IPv4 and IPv6 packets using the following TCP and UDP ports:

  • SIP using TCP port 5060
  • SIP Transport Layer Security (TLS) using TCP port 5061
  • SIP using UDP port 5060

An attacker could exploit the vulnerability using spoofed packets.

Vulnerability in the Session Initiation Protocol (SIP) implementation in Cisco IOS Software and Cisco IOS XE Software: This vulnerability can be exploited remotely without authentication and without end-user interaction. Successful exploitation of this vulnerability could cause a DoS condition. Repeated attempts to exploit this vulnerability could result in a sustained DoS condition. The attack vectors for exploitation are through IPv4 and IPv6 packets using the following protocols and ports:

  • SIP using TCP port 5060
  • SIP TLS using TCP port 5061
  • SIP using UDP port 5060

An attacker could exploit the vulnerability using spoofed packets.

Mitigation Technique Overview

Cisco devices provide several countermeasures for this vulnerability. Administrators are advised to consider these protection methods to be general security best practices for infrastructure devices and the traffic that transits the network. This section of the document provides an overview of these techniques.

Cisco IOS Software can provide effective means of exploit prevention using the following methods:

  • Infrastructure access control lists (iACLs)
  • Transit access control lists (tACLs)
  • Unicast Reverse Path Forwarding (uRPF)
  • IP source guard (IPSG)

These protection mechanisms filter and drop, as well as verify the source IP address of, packets that are attempting to exploit this vulnerability.

The proper deployment and configuration of uRPF provides an effective means of protection against attacks that use packets with spoofed source IP addresses. uRPF should be deployed as close to all traffic sources as possible.

The proper deployment and configuration of IPSG provides an effective means of protection against spoofing attacks at the access layer.

Effective means of exploit prevention can also be provided by the Cisco ASA 5500 Series Adaptive Security Appliance, Cisco Catalyst 6500 Series ASA Services Module (ASASM), and the Firewall Services Module (FWSM) for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers using the following:

  • iACLs
  • tACLs
  • uRPF

These protection mechanisms filter and drop, as well as verify the source IP address of, packets that are attempting to exploit this vulnerability.

Cisco IOS NetFlow records can provide visibility into network-based exploitation attempts.

Cisco IOS Software, Cisco ASA, Cisco ASASM, and Cisco FWSM firewalls can provide visibility through syslog messages and counter values displayed in the output from show commands.

Effective use of Cisco Intrusion Prevention System (IPS) event actions provides visibility into and protection against attacks that attempt to exploit this vulnerability.

The Cisco Security Manager can also provide visibility through incidents, queries, and event reporting.

Risk Management

Organizations are advised to follow their standard risk evaluation and mitigation processes to determine the potential impact of this vulnerability. Triage refers to sorting projects and prioritizing efforts that are most likely to be successful. Cisco has provided documents that can help organizations develop a risk-based triage capability for their information security teams. Risk Triage for Security Vulnerability Announcements and Risk Triage and Prototyping can help organizations develop repeatable security evaluation and response processes.

Device-Specific Mitigation and Identification

Caution: The effectiveness of any mitigation technique depends on specific customer situations such as product mix, network topology, traffic behavior, and organizational mission. As with any configuration change, evaluate the impact of this configuration prior to applying the change.

Specific information about mitigation and identification is available for these devices:

Cisco IOS Routers and Switches

Mitigation: Infrastructure Access Control Lists

To protect infrastructure devices and minimize the risk, impact, and effectiveness of direct infrastructure attacks, administrators are advised to deploy infrastructure access control lists (iACLs) to perform policy enforcement of traffic sent to infrastructure equipment. Administrators can construct an iACL by explicitly permitting only authorized traffic sent to infrastructure devices in accordance with existing security policies and configurations. For the maximum protection of infrastructure devices, deployed iACLs should be applied in the ingress direction on all interfaces to which an IP address has been configured. An iACL workaround cannot provide complete protection against this vulnerability when the attack originates from a trusted source address.

The iACL policy denies unauthorized SIP packets on TCP and UDP ports 5060 and SIP-TLS on TCP port 5061 that are sent to affected devices. In the following example, 192.168.60.0/24 and 2001:DB8:1:60::/64 represent the IP address space that is used by the affected devices, and the hosts at 192.168.100.1 and 2001:DB8:1:100::1 are considered trusted sources that require 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 TCP and UDP ports
!
permit tcp host 192.168.100.1 192.168.60.0 0.0.0.255 eq 5060 permit tcp host 192.168.100.1 192.168.60.0 0.0.0.255 eq 5061 permit udp host 192.168.100.1 192.168.60.0 0.0.0.255 eq 5060 !
!-- The following vulnerability-specific access control entries
!-- (ACEs) can aid in identification of attacks
!
deny tcp any 192.168.60.0 0.0.0.255 eq 5060 deny tcp any 192.168.60.0 0.0.0.255 eq 5061 deny udp any 192.168.60.0 0.0.0.255 eq 5060 !
!-- 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
!
!
!-- Create the corresponding IPv6 tACL
!
ipv6 access-list IPv6-Infrastructure-ACL-Policy !
!-- Include explicit permit statements for trusted sources
!-- that require access on the vulnerable protocols and ports
!
permit tcp host 2001:DB8:1:100::1 2001:DB8:1:60::/64 eq 5060 permit tcp host 2001:DB8:1:100::1 2001:DB8:1:60::/64 eq 5061 permit udp host 2001:DB8:1:100::1 2001:DB8:1:60::/64 eq 5060 !
!-- The following vulnerability-specific access control entries
!-- (ACEs) can aid in identification of attacks to global and
!-- link local addresses
!
deny tcp any 2001:DB8:1:60::/64 eq 5060 deny tcp any 2001:DB8:1:60::/64 eq 5061 deny udp any 2001:DB8:1:60::/64 eq 5060 !
!-- Permit other required traffic to the infrastructure address
!-- range and allow IPv6 Neighbor Discovery packets, which
!-- include Neighbor Solicitation packets and Neighbor
!-- Advertisement packets
!
permit icmp any any nd-ns permit icmp any any nd-na !
!-- Explicit deny for all other IPv6 traffic to the global
!-- infrastructure address range
!
deny ipv6 any 2001:DB8:1:60::/64 !
!-- Permit or deny all other Layer 3 and Layer 4 traffic
!-- in accordance with existing security policies and configurations
!
!
!-- Apply tACLs to interfaces in the ingress direction
!
interface GigabitEthernet0/0 ip access-group Infrastructure-ACL-Policy in ipv6 traffic-filter IPv6-Infrastructure-ACL-Policy in

Note that filtering with an interface access list will elicit the transmission of ICMP unreachable messages back to the source of the filtered traffic. Generating these messages could have the undesired effect of increasing CPU utilization on the device. In Cisco IOS Software, ICMP unreachable generation is limited to one packet every 500 milliseconds by default. ICMP unreachable message generation can be disabled using the interface configuration command no ip unreachables. ICMP unreachable rate limiting can be changed from the default using the global configuration command ip icmp rate-limit unreachable interval-in-ms.

Identification: Infrastructure Access Control Lists

After the administrator applies the iACL to an interface, the show ip access-lists and show ipv6 access-list commands will identify the number of SIP packets on TCP and UDP port 5060 and SIP-TLS on TCP and UDP port 5061 that have been filtered on interfaces on which the iACL is applied. Administrators should investigate filtered packets to determine whether they are attempts to exploit this vulnerability. Example output for show ip access-lists Infrastructure-ACL-Policy follows:

router#show ip access-lists Infrastructure-ACL-Policy
Extended IP access list Infrastructure-ACL-Policy
    10 permit tcp host 192.168.100.1 192.168.60.0 0.0.0.255 eq 5060 (60 matches)
    20 permit tcp host 192.168.100.1 192.168.60.0 0.0.0.255 eq 5061 (41 matches)
    30 permit udp host 192.168.100.1 192.168.60.0 0.0.0.255 eq 5060 (188 matches)
    40 deny tcp any 192.168.60.0 0.0.0.255 eq 5060 (9 matches)
    50 deny tcp any 192.168.60.0 0.0.0.255 eq 5061 (18 matches)
    60 deny udp any 192.168.60.0 0.0.0.255 eq 5060 (34 matches)
    70 deny ip any 192.168.60.0 0.0.0.255 (17 matches)
router#

In the preceding example, access list Infrastructure-ACL-Policy has dropped the following packets that are received from an untrusted host or network:

  • 9 SIP packets on TCP port 5060 for ACE line 40
  • 18 SIP packets on TCP port 5061 for ACE line 50
  • 34 SIP packets on UDP port 5060 for ACE line 60
router#show ipv6 access-list IPv6-Infrastructure-ACL-Policy 
IPv6 access list IPv6-Infrastructure-ACL-Policy
    permit tcp host 2001:DB8:1:100::1 2001:DB8:1:60::/64 eq 5060 
      (71 matches) sequence 10
    permit tcp host 2001:DB8:1:100::1 2001:DB8:1:60::/64 eq 5061 
      (85 matches) sequence 20
    permit udp host 2001:DB8:1:100::1 2001:DB8:1:60::/64 eq 5060 
      (512 matches) sequence 30
    deny tcp any 2001:DB8:1:60::/64 eq 5060 (58 matches) sequence 40
    deny tcp any 2001:DB8:1:60::/64 eq 5061 (81 matches) sequence 50
    deny udp any 2001:DB8:1:60::/64 eq 5060 (216 matches) sequence 60
    permit icmp any any nd-ns (80 matches) sequence 70
    permit icmp any any nd-na (80 matches) sequence 80
    deny ipv6 any 2001:DB8:1:60::/64 (5 matches) sequence 90

In the preceding example, access list IPv6-Infrastructure-ACL-Policy has dropped the following

  • 58 SIP packets on TCP port 5060 for ACE line 40
  • 81 SIP packets on TCP port 5061 for ACE line 50
  • 216 SIP packets on UDP port 5060 for ACE line 60

For additional information about investigating incidents using ACE counters and syslog events, reference the Identifying Incidents Using Firewall and IOS Router Syslog Events Applied Intelligence white paper.

Administrators can use Embedded Event Manager to provide instrumentation when specific conditions are met, such as ACE counter hits. The Applied Intelligence white paper Embedded Event Manager in a Security Context provides additional details about how to use this feature.

Mitigation: Transit Access Control Lists

To protect the network from traffic that enters the network at ingress access points, which may include Internet connection points, partner and supplier connection points, or VPN connection points, administrators are advised to deploy transit access control lists (tACLs) to perform policy enforcement. Administrators can construct a tACL 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. A tACL workaround cannot provide complete protection against this vulnerability when the attack originates from a trusted source address.

The tACL policy denies unauthorized SIP IPv4 and IPv6 packets on TCP ports 5060 and 5061 and UDP port 5060 that are sent to affected devices. In the following example, 192.168.60.0/24 and 2001:DB8:1:60::/64 represent the IP address space that is used by the affected devices, and the hosts at 192.168.100.1 and 2001:DB8::100:1 are considered trusted sources that require access to the affected devices. Care should be taken to allow required traffic for routing and administrative access prior to denying all unauthorized traffic.

Additional information about tACLs is in Transit Access Control Lists: Filtering at Your Edge.

!
!-- Include explicit permit statements for trusted sources
!-- that require access on the vulnerable TCP and UDP ports

!

access-list 150 permit tcp host 192.168.100.1 192.168.60.0 0.0.0.255 eq 5060 access-list 150 permit tcp host 192.168.100.1 192.168.60.0 0.0.0.255 eq 5061 access-list 150 permit udp host 192.168.100.1 192.168.60.0 0.0.0.255 eq 5060 !
!-- The following vulnerability-specific access control entries
!-- (ACEs) can aid in identification of attacks
!
access-list 150 deny tcp any 192.168.60.0 0.0.0.255 eq 5060 access-list 150 deny tcp any 192.168.60.0 0.0.0.255 eq 5061 access-list 150 deny udp any 192.168.60.0 0.0.0.255 eq 5060 !
!-- Permit or deny all other Layer 3 and Layer 4 traffic in accordance
!-- with existing security policies and configurations
!
!-- Explicit deny for all other IP traffic
!

access-list 150 deny ip any any !
!-- Create the corresponding IPv6 tACL
!
ipv6 access-list IPv6-Transit-ACL-Policy !
!-- Include explicit permit statements for trusted sources
!-- that require access on the vulnerable TCP and UDP ports
!
permit tcp host 2001:DB8::100:1 2001:DB8:1:60::/64 eq 5060  permit tcp host 2001:DB8::100:1 2001:DB8:1:60::/64 eq 5061  permit udp host 2001:DB8::100:1 2001:DB8:1:60::/64 eq 5060
 !
 !-- The following vulnerability-specific ACEs can
!-- aid in identification of attacks to global and
!-- link-local addresses
!
 deny tcp any 2001:DB8:1:60::/64 eq 5060  deny tcp any 2001:DB8:1:60::/64 eq 5061  deny udp any 2001:DB8:1:60::/64 eq 5060
 !
 !-- Permit or deny all other Layer 3 and Layer 4 traffic in
!-- accordance with existing security policies and configurations
 !-- and allow IPv6 neighbor discovery packets, which
 !-- include neighbor solicitation packets and neighbor
 !-- advertisement packets
 !
 permit icmp any any nd-ns  permit icmp any any nd-na  !
!-- Explicit deny for all other IPv6 traffic
 !

deny ipv6 any any  !
!
!-- Apply tACLs to interfaces in the ingress direction
!
interface GigabitEthernet0/0  ip access-group 150 in  ipv6 traffic-filter IPv6-Transit-ACL-Policy in

Note that filtering with an interface access list will elicit the transmission of ICMP unreachable messages back to the source of the filtered traffic. Generating these messages could have the undesired effect of increasing CPU utilization on the device. In Cisco IOS Software, ICMP unreachable generation is limited to one packet every 500 milliseconds by default. ICMP unreachable message generation can be disabled using the interface configuration commands no ip unreachables and no ipv6 unreachables. ICMP unreachable rate limiting can be changed from the default using the global configuration commands ip icmp rate-limit unreachable interval-in-ms and ipv6 icmp error-interval interval-in-ms.

Identification: Transit Access Control Lists

After the administrator applies the tACL to an interface, the show ip access-lists and show ipv6 access-list commands will identify the number of SIP IPv4 and IPv6 packets on TCP ports 5060 and 5061 and UDP port 5060 that have been filtered. Administrators are advised to investigate filtered packets to determine whether they are attempts to exploit this vulnerability. Example output for show ip access-lists 150 and show ipv6 access-list IPv6-Transit-ACL-Policy follows:

router#show ip access-lists 150
Extended IP access list 150
    10 permit tcp host 192.168.100.1 192.168.60.0 0.0.0.255 eq 5060
    20 permit tcp host 192.168.100.1 192.168.60.0 0.0.0.255 eq 5061
    30 permit udp host 192.168.100.1 192.168.60.0 0.0.0.255 eq 5060
    40 deny tcp any 192.168.60.0 0.0.0.255 eq 5060 (57 matches)
    50 deny tcp any 192.168.60.0 0.0.0.255 eq 5061 (40 matches)
    60 deny udp any 192.168.60.0 0.0.0.255 eq 5060 (18 matches)
    70 deny ip any any
router#

In the preceding example, access list 150 has dropped the following packets received from an untrusted host or network:

  • 57 SIP packets on TCP port 5060 for ACE line 40
  • 40 SIP packets on TCP port 5061 for ACE line 50
  • 18 SIP packets on UDP port 5060 for ACE line 60
router#show ipv6 access-list IPv6-Transit-ACL-Policy 
IPv6 access list IPv6-Transit-ACL-Policy
    permit tcp host 2001:DB8::100:1 2001:DB8:1:60::/64 eq 5060 (55 matches) sequence 10
    permit tcp host 2001:DB8::100:1 2001:DB8:1:60::/64 eq 5061 (38 matches) sequence 20
    permit udp host 2001:DB8::100:1 2001:DB8:1:60::/64 eq 5060 (210 matches) sequence 30
    deny tcp any 2001:DB8:1:60::/64 eq 5060 (18 matches) sequence 40
    deny tcp any 2001:DB8:1:60::/64 eq 5061 (21 matches) sequence 50
    deny udp any 2001:DB8:1:60::/64 eq 5060 (87 matches) sequence 60
    permit icmp any any nd-ns (41 matches) sequence 70
    permit icmp any any nd-na (41 matches) sequence 80
    deny ipv6 any any (21 matches) sequence 90

In the preceding example, access list IPv6-Transit-ACL-Policy has dropped the following packets received from an untrusted host or network:

  • 18 SIP packets on TCP port 5060 for ACE line 40
  • 21 SIP packets on TCP port 5061 for ACE line 50
  • 87 SIP packets on UDP port 5060 for ACE line 60

For additional information about investigating incidents using ACE counters and syslog events, reference the Identifying Incidents Using Firewall and IOS Router Syslog Events Cisco Security Intelligence Operations white paper.

Administrators can use Embedded Event Manager to provide instrumentation when specific conditions are met, such as ACE counter hits. The Cisco Security Intelligence Operations white paper Embedded Event Manager in a Security Context provides additional details about how to use this feature.

Identification: Access List Logging

The log and log-input access control list (ACL) option will cause packets that match specific ACEs to be logged. The log-input option enables logging of the ingress interface in addition to the packet source and destination IP addresses and ports.

Caution: Access control list logging can be very CPU intensive and must be used with extreme caution. Factors that drive the CPU impact of ACL logging are log generation, log transmission, and process switching to forward packets that match log-enabled ACEs.

For Cisco IOS Software, the ip access-list logging interval interval-in-ms command can limit the effects of process switching induced by IPv4 ACL logging. The logging rate-limit rate-per-second [except loglevel] command limits the impact of log generation and transmission.

The CPU impact from ACL logging can be addressed in hardware on the Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers with Supervisor Engine 720 or Supervisor Engine 32 using optimized ACL logging.

For additional information about the configuration and use of ACL logging, reference the Understanding Access Control List Logging Cisco Security Intelligence Operations white paper.

Mitigation: Spoofing Protection

Unicast Reverse Path Forwarding

The vulnerability that is described in this document can be exploited by spoofed IP packets. Administrators can deploy and configure Unicast Reverse Path Forwarding (uRPF) as a protection mechanism against spoofing.

uRPF is configured at the interface level and can detect and drop packets that lack a verifiable source IP address. Administrators should not rely on uRPF to provide complete spoofing protection because spoofed packets may enter the network through a uRPF-enabled interface if an appropriate return route to the source IP address exists. Administrators are advised to take care to ensure that the appropriate uRPF mode (loose or strict) is configured during the deployment of this feature because it can drop legitimate traffic that is transiting the network. In an enterprise environment, uRPF may be enabled at the Internet edge and the internal access layer on the user-supporting Layer 3 interfaces.

Identification: Spoofing Protection Using Unicast Reverse Path Forwarding

With uRPF properly deployed and configured throughout the network infrastructure, administrators can use the show cef interface type slot/port internal, show ip interface, show cef drop, show ip cef switching statistics feature, and show ip traffic commands to identify the number of packets that uRPF has dropped.

Note: Beginning with Cisco IOS Software Release 12.4(20)T, the command show ip cef switching has been replaced by show ip cef switching statistics feature.

Note: The show command | begin regex and show command | include regex command modifiers are used in the following examples to minimize the amount of output that administrators will need to parse to view the desired information. Additional information about command modifiers is in the show command sections of the Cisco IOS Configuration Fundamentals Command Reference.

router#show cef interface GigabitEthernet 0/0 internal | include drop
ip verify: via=rx (allow default), acl=0, drop=18, sdrop=0
router#

Note: show cef interface type slot/port internal is a hidden command that must be fully entered at the command-line interface. Command completion is not available for it.

router#show ip interface GigabitEthernet 0/0 | begin verify
  IP verify source reachable-via RX, allow default, allow self-ping
  18 verification drops
  0 suppressed verification drops
router#

router#show cef drop
CEF Drop Statistics
Slot  Encap_fail  Unresolved Unsupported    No_route      No_adj  ChkSum_Err
RP            27           0           0          18           0           0
router#

router#show ip cef switching statistics feature IPv4 CEF input features:
Path Feature Drop Consume Punt Punt2Host Gave route
RP PAS uRPF 18 0 0 0 0
Total 18 0 0 0 0 -- CLI Output Truncated -- router# router#show ip traffic | include RPF 18 no route, 18 unicast RPF, 0 forced drop router#

In the preceding show cef interface GigabitEthernet 0/0 internal, show ip interface GigabitEthernet 0/0, show cef drop, show ip cef switching statistics feature, and show ip traffic examples, uRPF has dropped 18 IP packets received globally on all interfaces with uRPF configured because of the inability to verify the source address of the IP packets within the forwarding information base of Cisco Express Forwarding.

Additional information is in the Unicast Reverse Path Forwarding Loose Mode Feature Guide.

For additional information about the configuration and use of uRPF, reference the Understanding Unicast Reverse Path Forwarding Cisco Security Intelligence Operations white paper.

IP Source Guard

IP source guard (IPSG) is a security feature that restricts IP traffic on nonrouted, Layer 2 interfaces by filtering packets based on the DHCP snooping binding database and manually configured IP source bindings. Administrators can use IPSG to prevent attacks from an attacker who attempts to spoof packets by forging the source IP address and/or the MAC address. When properly deployed and configured, IPSG coupled with strict mode uRPF provides the most effective means of spoofing protection for the vulnerability that is described in this document.

Additional information about the deployment and configuration of IPSG is in Configuring DHCP Features and IP Source Guard.

Cisco IOS NetFlow and Cisco IOS Flexible NetFlow

Identification: IPv4 Traffic Flow Identification Using Cisco IOS NetFlow

Administrators can configure Cisco IOS NetFlow on Cisco IOS routers and switches to aid in the identification of IPv4 traffic flows that may be attempts to exploit this vulnerability. Administrators are advised to investigate flows to determine whether they are attempts to exploit this vulnerability or whether they are legitimate traffic flows.

router#show ip cache flow
IP packet size distribution (90784136 total packets):
   1-32   64   96  128  160  192  224  256  288  320  352  384  416  448  480
   .000 .698 .011 .001 .004 .005 .000 .004 .000 .000 .003 .000 .000 .000 .000
    512  544  576 1024 1536 2048 2560 3072 3584 4096 4608
   .000 .001 .256 .000 .010 .000 .000 .000 .000 .000 .000

IP Flow Switching Cache, 4456704 bytes 1885 active, 63651 inactive, 59960004 added 129803821 ager polls, 0 flow alloc failures Active flows timeout in 30 minutes Inactive flows timeout in 15 seconds IP Sub Flow Cache, 402056 bytes 0 active, 16384 inactive, 0 added, 0 added to flow 0 alloc failures, 0 force free 1 chunk, 1 chunk added last clearing of statistics never Protocol Total Flows Packets Bytes Packets Active(Sec) Idle(Sec) -------- Flows /Sec /Flow /Pkt /Sec /Flow /Flow TCP-Telnet 11393421 2.8 1 48 3.1 0.0 1.4 TCP-FTP 236 0.0 12 66 0.0 1.8 4.8 TCP-FTPD 21 0.0 13726 1294 0.0 18.4 4.1 TCP-WWW 22282 0.0 21 1020 0.1 4.1 7.3 TCP-X 719 0.0 1 40 0.0 0.0 1.3 TCP-BGP 1 0.0 1 40 0.0 0.0 15.0 TCP-Frag 70399 0.0 1 688 0.0 0.0 22.7 TCP-other 47861004 11.8 1 211 18.9 0.0 1.3 UDP-DNS 582 0.0 4 73 0.0 3.4 15.4 UDP-NTP 287252 0.0 1 76 0.0 0.0 15.5 UDP-other 310347 0.0 2 230 0.1 0.6 15.9 ICMP 11674 0.0 3 61 0.0 19.8 15.5 IPv6INIP 15 0.0 1 1132 0.0 0.0 15.4 GRE 4 0.0 1 48 0.0 0.0 15.3 Total: 59957957 14.8 1 196 22.5 0.0 1.5

SrcIf SrcIPaddress DstIf DstIPaddress Pr SrcP DstP Pkts
Gi0/0 192.168.10.201 Gi0/1 192.168.60.102 11 0984 13C4 1
Gi0/0 192.168.11.54 Gi0/1 192.168.60.158 06 0911 13C5 3
Gi0/1 192.168.150.60 Gi0/0 10.89.16.226 06 0016 12CA 1
Gi0/0 192.168.13.97 Gi0/1 192.168.60.28 06 0B3E 13C4 5

Gi0/0 192.168.10.17 Gi0/1 192.168.60.97 11 0B89 13C5 1 Gi0/0 10.88.226.1 Gi0/1 192.168.202.22 11 007B 007B 1
Gi0/0 192.168.12.185 Gi0/1 192.168.60.239 11 0BD7 13C4 1
Gi0/0 10.89.16.226 Gi0/1 192.168.150.60 06 12CA 0016 1 router#

In the preceding example, there are multiple flows for SIP on TCP ports 5060 (hex value 13C4) and 5061 (hex value 13C5) and UDP port 5060 (hex value 13C4).

This traffic is sourced from and sent to addresses within the 192.168.60.0/24 address block, which is used by affected devices. The packets in these flows may be spoofed and may indicate an attempt to exploit this vulnerability. Administrators are advised to compare these flows to baseline utilization for SIP traffic sent on UDP port 5060 and also investigate the flows to determine whether they are sourced from untrusted hosts or networks.

As shown in the following example, to view only the SIP packets on TCP port 5060 (hex value 13C4) and TCP port 5061 (hex value 13C5), use the show ip cache flow | include SrcIf|_06_.*(13C4|13C5)_ command to display the related Cisco NetFlow records:

TCP Flows
router#show ip cache flow | include SrcIf|_06_.*(13C4|13C5)_
SrcIf         SrcIPaddress     DstIf         DstIPaddress    Pr SrcP DstP  Pkts
Gi0/0 192.168.12.110 Gi0/1 192.168.60.163 06 092A 13C5 6
Gi0/0 192.168.11.230 Gi0/1 192.168.60.20 06 0C09 13C4 1
Gi0/0 192.168.11.131 Gi0/1 192.168.60.245 06 0B66 13C4 18
Gi0/0 192.168.13.7 Gi0/1 192.168.60.162 06 0914 13C5 1
Gi0/0 192.168.41.86 Gi0/1 192.168.60.27 06 0B7B 13C5 2
router#

As shown in the following example, to view only the SIP packets on UDP port 5060 (hex value 13C4), use the show ip cache flow | include SrcIf|_11_.*(13C4)_ command to display the related Cisco NetFlow records:

UDP Flows
router#show ip cache flow | include SrcIf|_11_.*(13C4)_
SrcIf         SrcIPaddress     DstIf         DstIPaddress    Pr SrcP DstP  Pkts
Gi0/0 192.168.12.110 Gi0/1 192.168.60.183 11 392A 13C4 6
Gi0/0 192.168.11.230 Gi0/1 192.168.60.220 11 2809 13C4 1
Gi0/0 192.168.13.7 Gi0/1 192.168.60.12 11 1914 13C4 1
Gi0/0 192.168.41.86 Gi0/1 192.168.60.127 11 3B7B 13C4 2
router#

Identification: IPv6 Traffic Flow Identification Using Cisco IOS NetFlow

Administrators can configure Cisco IOS NetFlow on Cisco IOS routers and switches to aid in the identification of IPv6 traffic flows that may be attempts to exploit the vulnerability that is described in this document. Administrators are advised to investigate flows to determine whether they are attempts to exploit this vulnerability or whether they are legitimate traffic flows.

The following output is from a Cisco IOS device running Cisco IOS Software 12.4 mainline train. The command syntax will vary for different Cisco IOS Software trains.

router#show ipv6 flow cache
IP packet size distribution (50078919 total packets):
   1-32  64   96  128  160  192  224  256  288  320  352  384  416  448  480
   .000 .990 .001 .008 .000 .000 .000 .000 .000 .000 .000 .000 .000 .000 .000
    512  544  576 1024 1536 2048 2560 3072 3584 4096 4608
   .000 .000 .000 .000 .000 .000 .000 .000 .000 .000 .000

IP Flow Switching Cache, 475168 bytes 8 active, 4088 inactive, 6160 added 1092984 ager polls, 0 flow alloc failures Active flows timeout in 30 minutes Inactive flows timeout in 15 seconds

IP Sub Flow Cache, 33928 bytes 16 active, 1008 inactive, 12320 added, 6160 added to flow 0 alloc failures, 0 force free 1 chunk, 1 chunk added

SrcAddress InpIf DstAddress OutIf Prot SrcPrt DstPrt Packets 2001:DB...06::201 Gi0/0 2001:DB...28::20 Local 0x11 0x16C4 0x13C4 1464 2001:DB...6A:5BA6 Gi0/0 2001:DB...28::21 Gi0/1 0x3A 0x0000 0x8000 1191 2001:DB...6A:5BA6 Gi0/0 2001:DB...134::3 Gi0/1 0x3A 0x0000 0x8000 1191 2001:DB...6A:5BA6 Gi0/0 2001:DB...128::4 Gi0/1 0x3A 0x0000 0x8000 1192
2001:DB...6A:5BA6 Gi0/0 2001:DB...128::2 Gi0/1 0x06 0x160A 0x13C4 1597 2001:DB...06::201 Gi0/0 2001:DB...128::3 Gi0/1 0x06 0x1610 0x13C5 1001 2001:DB...06::201 Gi0/0 2001:DB...128::4 Gi0/1 0x11 0x1634 0x13C4 1292
2001:DB...6A:5BA6 Gi0/0 2001:DB...128::3 Gi0/1 0x3A 0x0000 0x8000 1155 2001:DB...6A:5BA6 Gi0/0 2001:DB...146::3 Gi0/1 0x3A 0x0000 0x8000 1092 2001:DB...6A:5BA6 Gi0/0 2001:DB...144::4 Gi0/1 0x3A 0x0000 0x8000 1193

To permit display of the full 128-bit IPv6 address, use the terminal width 132 exec mode command.

In the preceding example, there are multiple IPv6 flows for SIP on TCP ports 5060 (hex value 13C4) and 5061 (hex value 13C5) and UDP port 5060 (hex value 13C4).

The SIP packets on UDP port 5060 are sourced from and sent to addresses within the 2001:DB8:1:60::/64 address block that is used by affected devices. The packets in the UDP flows may be spoofed and could indicate an attempt to exploit this vulnerability. Administrators are advised to compare these flows to baseline utilization for SIP traffic on UDP port 5060 and also investigate the flows to determine whether they are sourced from untrusted hosts or networks.

As shown in the following example, to view only the SIP packets on TCP ports 5060 (hex value 13C4) and 5061 (hex value 13C5), use the show ipv6 flow cache | include SrcIf|_06_.*(13C4|13C5)_ command to display the related Cisco NetFlow records:

TCP Flows

router#show ipv6 flow cache | include SrcIf|_06_.*(13C4|13C5)_
SrcAddress        InpIf    DstAddress       OutIf    Prot SrcPrt DstPrt Packets
2001:DB...6A:5BA6 Gi0/0    2001:DB...128::2 Gi0/1    0x06 0x160A 0x13C5 1597
2001:DB...06::201 Gi0/0 2001:DB...128::3 Gi0/1 0x06 0x1610 0x13C4 1001
router#

As shown in the following example, to view only the SIP packets on UDP ports 5060 (hex value 13C4), use the show ipv6 flow cache | include SrcIf|_11_.*(13C4)_ command to display the related Cisco NetFlow records:

UDP Flows

router#show ipv6 flow cache | include SrcIf|_11_.*(13C4)_
SrcAddress        InpIf    DstAddress       OutIf    Prot SrcPrt DstPrt Packets
2001:DB...06::201 Gi0/0    2001:DB...28::20 Local    0x11 0x16C4 0x13C4 1464 
2001:DB...06::201 Gi0/0 2001:DB...128::3 Gi0/1 0x11 0x1610 0x13C5 1001
2001:DB...06::201 Gi0/0 2001:DB...128::4 Gi0/1 0x11 0x1634 0x13C4 1292
router#

Identification: IPv4 Traffic Flow Identification Using Cisco Flexible NetFlow

Introduced in Cisco IOS Software Releases 12.2(31)SB2 and 12.4(9)T, Cisco IOS Flexible NetFlow improves original Cisco NetFlow by adding the capability to customize the traffic analysis parameters for the administrator's specific requirements. Original Cisco NetFlow uses a fixed seven tuples of IP information to identify a flow, whereas Cisco IOS Flexible NetFlow allows the flow to be user defined. It facilitates the creation of more complex configurations for traffic analysis and data export by using reusable configuration components.

The following example output is from a Cisco IOS device that is running a version of Cisco IOS Software in the 15.1T train. Although the syntax will be almost identical for the 12.4T and 15.0 trains, it may vary slightly depending on the actual Cisco IOS release being used. In the following configuration, Cisco IOS Flexible NetFlow will collect information on interface GigabitEthernet0/0 for incoming IPv4 flows based on source IPv4 address, as defined by the match ipv4 source address key field statement. Cisco IOS Flexible NetFlow will also include nonkey field information about source and destination IPv4 addresses, protocol, ports (if present), ingress and egress interfaces, and packets per flow.

!
!-- Configure key and nonkey fields
!-- in the user-defined flow record
!
flow record FLOW-RECORD-ipv4 match ipv4 source address collect ipv4 protocol collect ipv4 destination address collect transport source-port collect transport destination-port collect interface input collect interface output collect counter packets !
!-- Configure the flow monitor to
!-- reference the user-defined flow
!-- record
!
flow monitor FLOW-MONITOR-ipv4 record FLOW-RECORD-ipv4 !
!-- Apply the flow monitor to the interface
!-- in the ingress direction
!
interface GigabitEthernet0/0 ip flow monitor FLOW-MONITOR-ipv4 input

The Cisco IOS Flexible NetFlow flow output is as follows:

router#show flow monitor FLOW-MONITOR-ipv4 cache format table
  Cache type:                               Normal
  Cache size:                                 4096
  Current entries:                               6
  High Watermark:                                1
  Flows added:                                   9181
  Flows aged:                                    9175
    - Active timeout      (  1800 secs)          9000
    - Inactive timeout    (    15 secs)           175
    - Event aged                                    0
    - Watermark aged                                0
    - Emergency aged                                0

IPV4 SRC ADDR     ipv4 dst addr trns src port trns dst port intf input intf output   pkts ip prot
=============== =============== ============= ============= ========== ===========  ===== =======
 192.168.10.201  192.168.60.102          1456          5060      Gi0/0       Gi0/1   1128       6
  192.168.11.54  192.168.60.158          4123          5061      Gi0/0       Gi0/1   2212      17
 192.168.150.60    10.89.16.226          2567           443      Gi0/0       Gi0/1     13       6
  192.168.13.97   192.168.60.28          3451          5061      Gi0/0       Gi0/1      1       6
  192.168.10.17   192.168.60.97          4231          5060      Gi0/0       Gi0/1    146      17
    10.88.226.1  192.168.202.22          2678           443      Gi0/0       Gi0/1  10567       6
   10.89.16.226  192.168.150.60          3562            80      Gi0/0       Gi0/1  30012       6

To view only SIP on TCP ports 5060 and 5061, use the show flow monitor FLOW-MONITOR-ipv4 cache format table | include IPV4 DST ADDR |_6_.*(5060|5061)_ command to display the related NetFlow records.

To view only SIP on UDP ports 5060, use the show flow monitor FLOW-MONITOR-ipv4 cache format table | include IPV4 DST ADDR |_17_.*(5060)_ command to display the related NetFlow records.

For more information about Cisco IOS Flexible NetFlow, refer to Flexible Netflow Configuration Guide, Cisco IOS Release 15.1M&T and Cisco IOS Flexible NetFlow Configuration Guide, Release 12.4T.

Identification: IPv6 Traffic Flow Identification Using Cisco IOS Flexible NetFlow

The following example output is from a Cisco IOS device that is running a version of Cisco IOS Software in the 15.1T train. Although the syntax will be almost identical for the 12.4T and 15.0 trains, it may vary slightly depending on the actual Cisco IOS release being used. In the following configuration, Cisco IOS Flexible NetFlow will collect information on interface GigabitEthernet0/0 for incoming IPv6 flows based on the source IPv6 address, as defined by the match ipv6 source address key field statement. Cisco IOS Flexible NetFlow will also include nonkey field information about source and destination IPv6 addresses, protocol, ports (if present), ingress and egress interfaces, and packets per flow.
!
!-- Configure key and nonkey fields
!-- in the user-defined flow record
!
flow record FLOW-RECORD-ipv6 match ipv6 source address collect ipv6 protocol collect ipv6 destination address collect transport source-port collect transport destination-port collect interface input collect interface output collect counter packets !
!-- Configure the flow monitor to
!-- reference the user-defined flow
!-- record
!
flow monitor FLOW-MONITOR-ipv6 record FLOW-RECORD-ipv6 !
!-- Apply the flow monitor to the interface
!-- in the ingress direction
!
interface GigabitEthernet0/0 ipv6 flow monitor FLOW-MONITOR-ipv6 input

The Cisco IOS Flexible NetFlow flow output is as follows:

router#show flow monitor FLOW-MONITOR-ipv6 cache format table
  Cache type:                               Normal
  Cache size:                                 4096
  Current entries:                               6
  High Watermark:                                2
  Flows added:                                   539
  Flows aged:                                    532
    - Active timeout      (  1800 secs)          350
    - Inactive timeout    (    15 secs)          182
    - Event aged                                   0
    - Watermark aged                               0
    - Emergency aged                               0

IPV6 SRC ADDR          ipv6 dst addr trns src port trns dst port intf input intf output  pkts ip prot
==================  ================ ============= ============= ========== ===========  ==== =======
 2001:DB...06::201  2001:DB...28::20           123           123      Gi0/0       Gi0/0    17      17
 2001:DB...06::201  2001:DB...28::20          1265          5061      Gi0/0       Gi0/0  1237       6
 2001:DB...06::201  2001:DB...28::20          1441          5061      Gi0/0       Gi0/0  2346       6
 2001:DB...06::201  2001:DB...28::20          1890          5060      Gi0/0       Gi0/0  5009       6
 2001:DB...06::201  2001:DB...28::20          2856          5060      Gi0/0       Gi0/0   486      17
 2001:DB...06::201  2001:DB...28::20          3012            53      Gi0/0       Gi0/0  1016      17
 2001:DB...06::201  2001:DB...28::20          2477          5061      Gi0/0       Gi0/0  1563      17

To permit display of the full 128-bit IPv6 address, use the terminal width 132 exec mode command.

To view only SIP on TCP ports 5060 and 5061, use the show flow monitor FLOW-MONITOR-ipv6 cache format table | include IPV6 DST ADDR|_6_.*(5060|5061)_ command to display the related Cisco IOS Flexible NetFlow records.

To view only SIP on UDP ports 5060, use the show flow monitor FLOW-MONITOR-ipv6 cache format table | include IPV6 DST ADDR|_17_.*(5060)_ command to display the related Cisco IOS Flexible NetFlow records.

Cisco ASA, Cisco ASASM, and Cisco FWSM Firewalls

Mitigation: Transit Access Control Lists

To protect the network from traffic that enters the network at ingress access points, which may include Internet connection points, partner and supplier connection points, or VPN connection points, administrators are advised to deploy tACLs to perform policy enforcement. Administrators can construct a tACL 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. A tACL workaround cannot provide complete protection against this vulnerability when the attack originates from a trusted source address.

The tACL policy denies unauthorized SIP IPv4 and IPv6 packets on TCP ports 5060 and 5061 and UDP port 5060 that are sent to affected devices. In the following example, 192.168.60.0/24 and 2001:DB8:1:60::/64 represent the IP address space that is used by the affected devices, and the hosts at 192.168.100.1 and 2001:DB8::100:1 are considered trusted sources that require access to the affected devices. Care should be taken to allow required traffic for routing and administrative access prior to denying all unauthorized traffic.

Additional information about tACLs is in Transit Access Control Lists: Filtering at Your Edge.

!
!-- Include explicit permit statements for trusted sources
!-- that require access on the vulnerable TCP and UDP ports
!

access-list tACL-Policy extended permit tcp host 192.168.100.1 192.168.60.0 255.255.255.0 eq 5060 access-list tACL-Policy extended permit tcp host 192.168.100.1 192.168.60.0 255.255.255.0 eq 5061 access-list tACL-Policy extended permit udp host 192.168.100.1 192.168.60.0 255.255.255.0 eq 5060 !
!-- The following vulnerability-specific access control entries
!-- (ACEs) can aid in identification of attacks
!

access-list tACL-Policy extended deny tcp any 192.168.60.0 255.255.255.0 eq 5060 access-list tACL-Policy extended deny tcp any 192.168.60.0 255.255.255.0 eq 5061 access-list tACL-Policy extended deny udp any 192.168.60.0 255.255.255.0 eq 5060 !
!-- Permit or deny all other Layer 3 and Layer 4 traffic in accordance
!-- with existing security policies and configurations
!
!-- Explicit deny for all other IP traffic
!

access-list tACL-Policy extended deny ip any any !
!-- Create the corresponding IPv6 tACL
!
!-- Include explicit permit statements for trusted sources
!-- that require access on the vulnerable TCP and UDP ports
!
ipv6 access-list IPv6-tACL-Policy permit tcp host 2001:DB8::100:1 2001:db8:1:60::/64 eq 5060 ipv6 access-list IPv6-tACL-Policy permit tcp host 2001:DB8::100:1 2001:db8:1:60::/64 eq 5061 ipv6 access-list IPv6-tACL-Policy permit udp host 2001:DB8::100:1 2001:db8:1:60::/64 eq 5060 !
!-- The following vulnerability-specific access control entries
!-- (ACEs) can aid in identification of attacks
!
ipv6 access-list IPv6-tACL-Policy deny tcp any 2001:db8:1:60::/64 eq 5060 ipv6 access-list IPv6-tACL-Policy deny tcp any 2001:db8:1:60::/64 eq 5061 ipv6 access-list IPv6-tACL-Policy deny udp any 2001:db8:1:60::/64 eq 5060 !
!-- Permit or deny all other Layer 3 and Layer 4 traffic in accordance
!-- with existing security policies and configurations
!
!-- Explicit deny for all other IP traffic
!
ipv6 access-list IPv6-tACL-Policy deny ip any any !
!-- Apply tACLs to interfaces in the ingress direction
!
access-group tACL-Policy in interface outside access-group IPv6-tACL-Policy in interface outside

Identification: Transit Access Control Lists

After the tACL has been applied to an interface, administrators can use the show access-list command to identify the number of SIP IPv4 and IPv6 packets on TCP ports 5060 and 5061 and UDP port 5060 that have been filtered. Administrators are advised to investigate filtered packets to determine whether they are attempts to exploit this vulnerability. Example output for show access-list tACL-Policy and show access-list IPv6-tACL-Policy follows:

firewall#show access-list tACL-Policy
access-list tACL-Policy; 7 elements; name hash: 0x3452703d
access-list tACL-Policy line 1 extended permit tcp host 192.168.100.1 
     192.168.60.0 255.255.255.0 eq sip (hitcnt=31)
access-list tACL-Policy line 2 extended permit tcp host 192.168.100.1 
     192.168.60.0 255.255.255.0 eq 5061 (hitcnt=61)
access-list tACL-Policy line 3 extended permit udp host 192.168.100.1 
     192.168.60.0 255.255.255.0 eq sip (hitcnt=131)
access-list tACL-Policy line 4 extended deny tcp any 192.168.60.0 
     255.255.255.0 eq sip (hitcnt=8)
access-list tACL-Policy line 5 extended deny tcp any 192.168.60.0 
     255.255.255.0 eq 5061 (hitcnt=14)
access-list tACL-Policy line 6 extended deny udp any 192.168.60.0 
     255.255.255.0 eq sip (hitcnt=30)
access-list tACL-Policy line 7 extended deny ip any any (hitcnt=8)

In the preceding example, access list tACL-Policy has dropped the following packets received from an untrusted host or network:

  • 8 SIP packets on TCP port 5060 for ACE line 4
  • 14 SIP packets on TCP port 5061 for ACE line 5
  • 30 SIP packets on UDP port 5060 for ACE line 6
firewall#show access-list IPv6-tACL-Policy                 
ipv6 access-list IPv6-tACL-Policy; 7 elements; name hash: 0x566a4229
ipv6 access-list IPv6-tACL-Policy line 1 permit tcp host 2001:db8:1:100::1 
     2001:db8:1:60::/64 eq sip (hitcnt=59) 
ipv6 access-list IPv6-tACL-Policy line 2 permit tcp host 2001:db8:1:100::1 
     2001:db8:1:60::/64 eq 5061 (hitcnt=28) 
ipv6 access-list IPv6-tACL-Policy line 3 permit udp host 2001:db8:1:100::1 
     2001:db8:1:60::/64 eq sip (hitcnt=124) 
ipv6 access-list IPv6-tACL-Policy line 4 deny tcp any 
     2001:db8:1:60::/64 eq sip (hitcnt=47)
ipv6 access-list IPv6-tACL-Policy line 5 deny tcp any 
     2001:db8:1:60::/64 eq 5061 (hitcnt=33) 
ipv6 access-list IPv6-tACL-Policy line 6 deny udp any 
     2001:db8:1:60::/64 eq sip (hitcnt=216) 
ipv6 access-list IPv6-tACL-Policy line 7 deny ip any any (hitcnt=27)

In the preceding example, access list IPv6-tACL-Policy has dropped the following packets received from an untrusted host or network:

  • 47 SIP packets on TCP port 5060 for ACE line 4
  • 33 SIP packets on TCP port 5061 for ACE line 5
  • 216 SIP packets on UDP port 5060 for ACE line 6

In addition, syslog message 106023 can provide valuable information, which includes the source and destination IP address, the source and destination port numbers, and the IP protocol for the denied packet.

Identification: Firewall Access List Syslog Messages

Firewall syslog message 106023 will be generated for packets denied by an access control entry (ACE) that does not have the log keyword present. Additional information about this syslog message is in Cisco ASA 5500 Series System Log Message, 8.2 - 106023.

Information about configuring syslog for the Cisco ASA 5500 Series Adaptive Security Appliance is in Monitoring - Configuring Logging. Information about configuring syslog on the Cisco Catalyst 6500 Series ASA Services Module is in Configuring Logging. Information about configuring syslog on the FWSM for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers is in Monitoring the Firewall Services Module.

In the following example, the show logging | grep regex command extracts syslog messages from the logging buffer on the firewall. These messages provide additional information about denied packets that could indicate potential attempts to exploit the vulnerability that is described in this document. It is possible to use different regular expressions with the grep keyword to search for specific data in the logged messages.

Additional information about regular expression syntax is in Creating a Regular Expression.

firewall#show logging | grep 106023
  Sep 26 2012 00:15:13: %ASA-4-106023: Deny udp src outside:192.0.2.200/2945 
         dst inside:192.168.60.33/5060 by access-group "tACL-Policy"
  Sep 26 2012 00:15:13: %ASA-4-106023: Deny tcp src outside:192.0.2.88/2949 
         dst inside:192.168.60.38/5060 by access-group "tACL-Policy"
  Sep 26 2012 00:15:13: %ASA-4-106023: Deny tcp src outside:192.0.2.175/2950 
         dst inside:192.168.60.250/5060 by access-group "tACL-Policy"
  Sep 26 2012 00:15:13: %ASA-4-106023: Deny udp src outside:2001:db8:2::2:172/2951
         dst inside:2001:db8:1:60::23/5060 by access-group "IPv6-tACL-Policy"
  Sep 26 2012 00:15:13: %ASA-4-106023: Deny tcp src outside:2001:db8:d::a85e:172/2952
         dst inside:2001:db8:1:60::134/5061 by access-group "IPv6-tACL-Policy"
firewall#

In the preceding example, the messages logged for the tACL tACL-Policy show potentially spoofed SIP packets for UDP port 5060 sent to the address block assigned to affected devices.

Additional information about syslog messages for Cisco ASA Series Adaptive Security Appliances is in Cisco ASA 5500 Series System Log Messages, 8.2. Additional information about syslog messages for Cisco Catalyst 6500 Series ASA Services Module is in the Analyzing Syslog Messages section of the Cisco ASASM CLI Configuration Guide. Additional information about syslog messages for the Cisco FWSM is in Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Logging System Log Messages.

For additional information about investigating incidents using syslog events, reference the Identifying Incidents Using Firewall and IOS Router Syslog Events Cisco Security Intelligence Operations white paper.

Mitigation: Spoofing Protection Using Unicast Reverse Path Forwarding

The vulnerability that is described in this document can be exploited by spoofed IP packets. Administrators can deploy and configure uRPF as a protection mechanism against spoofing.

uRPF is configured at the interface level and can detect and drop packets that lack a verifiable source IP address. Administrators should not rely on uRPF to provide complete spoofing protection because spoofed packets may enter the network through a uRPF-enabled interface if an appropriate return route to the source IP address exists. In an enterprise environment, uRPF may be enabled at the Internet edge and at the internal access layer on the user-supporting Layer 3 interfaces.

For additional information about the configuration and use of uRPF, reference the Cisco Security Appliance Command Reference for ip verify reverse-path and the Understanding Unicast Reverse Path Forwarding Cisco Security Intelligence Operations white paper.

Identification: Spoofing Protection Using Unicast Reverse Path Forwarding

Firewall syslog message 106021 will be generated for packets denied by uRPF. Additional information about this syslog message is in Cisco ASA 5500 Series System Log Message, 8.2 - 106021.

Information about configuring syslog for the Cisco ASA 5500 Series Adaptive Security Appliance is in Monitoring - Configuring Logging. Information about configuring syslog for the Cisco Catalyst 6500 Series ASA Services Module is in Configuring Logging. Information about configuring syslog on the FWSM for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers is in Monitoring the Firewall Services Module.

In the following example, the show logging | grep regex command extracts syslog messages from the logging buffer on the firewall. These messages provide additional information about denied packets that could indicate potential attempts to exploit the vulnerability that is described in this document. It is possible to use different regular expressions with the grep keyword to search for specific data in the logged messages.

Additional information about regular expression syntax is in Creating a Regular Expression.

firewall#show logging | grep 106021
  Sep 26 2012 00:15:13: %ASA-1-106021: Deny UDP reverse path check from
         192.168.60.1 to 192.168.60.100 on interface outside
  Sep 26 2012 00:15:13: %ASA-1-106021: Deny UDP reverse path check from
         192.168.60.1 to 192.168.60.100 on interface outside
  Sep 26 2012 00:15:13: %ASA-1-106021: Deny TCP reverse path check from
         192.168.60.1 to 192.168.60.100 on interface outside

The show asp drop command can also identify the number of packets that the uRPF feature has dropped, as shown in the following example:

firewall#show asp drop frame rpf-violated
Reverse-path verify failed 11
firewall#

In the preceding example, uRPF has dropped 11 IP packets received on interfaces with uRPF configured. Absence of output indicates that the uRPF feature on the firewall has not dropped packets.

For additional information about debugging accelerated security path dropped packets or connections, reference the Cisco Security Appliance Command Reference for show asp drop.

Cisco Security Manager

Identification: Cisco Security Manager

Cisco Security Manager, Event Viewer

Beginning in software version 4.0, Cisco Security Manager can collect syslogs from Cisco firewalls and Cisco IPS devices and provides the Event Viewer, which can query for events that are related to the vulnerability that is described in this document.

Using the following filters in the Firewall Denied Events predefined view in the Event Viewer provides all captured Cisco firewall access list deny syslog messages that could indicate potential attempts to exploit the vulnerability that is described in this document.

  • Use the Destination event filter to filter network objects that contain the IP address space that is used by the affected devices (for example, IPv4 address range 192.168.60.0/24 and IPv6 address range 2001:DB8:1:60::/64)
  • Use the Destination Service event filter to filter objects that contain TCP ports 5060 and 5061 and UDP port 5060

An Event Type ID filter can be used with the Firewall Denied Events predefined view in the Event Viewer to filter the syslog IDs shown in the following list to provide all captured Cisco firewall deny syslog messages that could indicate potential attempts to exploit the vulnerability that is described in this document:

  • ASA-4-106021 (uRPF spoofing)
  • ASA-4-106023 (ACL deny)

For more information about Cisco Security Manager Events, refer to the Filtering and Querying Events section of the Cisco Security Manager User Guide.

Identification: Event Management System Partner Events

Cisco works with industry-leading Security Information and Event Management (SIEM) companies through the Cisco Developer Network. This partnership helps Cisco deliver validated and pretested SIEM systems that address business concerns such as long-term log archiving and forensics, heterogeneous event correlation, and advanced compliance reporting. Security Information and Event Management partner products can be leveraged to collect events from Cisco devices and then query the collected events for the incidents created by a deny syslog messages from firewalls that could indicate potential attempts to exploit the vulnerability that is described in this document. The queries can be made by Syslog ID as shown in the following list:

  • ASA-4-106021 (uRPF spoofing)
  • ASA-4-106023 (ACL deny)

For more information about SIEM partners, refer to the Security Management System website.

Additional Information

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.

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/web/about/security/psirt/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.

Related Information

 
Alert History
 
Initial Release


Product Sets
 
The security vulnerability applies to the following combinations of products.

Primary Products:
CiscoCisco Unified Communications Manager 6.1 (1), (1a), (1b), (2), (2)SU1, (2)SU1a, (3), (4), (5) | 7.0 Base, (1), (2) | 7.1 Base, (3), (5), (5b) | 8.0 Base, (2c), (3) | 8.5 Base | 8.6 Base
CiscoIOS 12.2B 12.2(15)B, 12.2(15)B1, 12.2(16)B, 12.2(16)B1, 12.2(16)B2, 12.2(16)B3 | 12.2BX 12.2(16)BX, 12.2(16)BX1, 12.2(16)BX2, 12.2(16)BX3 | 12.2CZ 12.2(15)CZ, 12.2(15)CZ1, 12.2(15)CZ2, 12.2(15)CZ3 | 12.2MC 12.2(15)MC1a, 12.2(15)MC1b, 12.2(15)MC1c, 12.2(15)MC2 | 12.2T 12.2(11)T, 12.2(11)T1, 12.2(11)T10, 12.2(11)T11, 12.2(11)T2, 12.2(11)T3, 12.2(11)T4, 12.2(11)T5, 12.2(11)T6, 12.2(11)T7, 12.2(11)T8, 12.2(11)T9, 12.2(13)T, 12.2(13)T1, 12.2(13)T1a, 12.2(13)T10, 12.2(13)T11, 12.2(13)T12, 12.2(13)T13, 12.2(13)T14, 12.2(13)T15, 12.2(13)T16, 12.2(13)T17, 12.2(13)T2, 12.2(13)T3, 12.2(13)T4, 12.2(13)T5, 12.2(13)T6, 12.2(13)T7, 12.2(13)T8, 12.2(13)T8a, 12.2(13)T9, 12.2(15)T, 12.2(15)T1, 12.2(15)T1a, 12.2(15)T10, 12.2(15)T11, 12.2(15)T12, 12.2(15)T12a, 12.2(15)T13, 12.2(15)T14, 12.2(15)T15, 12.2(15)T16, 12.2(15)T17, 12.2(15)T2, 12.2(15)T3, 12.2(15)T4, 12.2(15)T4a, 12.2(15)T4c, 12.2(15)T4d, 12.2(15)T4e, 12.2(15)T5, 12.2(15)T5a, 12.2(15)T6, 12.2(15)T7, 12.2(15)T8, 12.2(15)T9, 12.2(15)T9a | 12.2YC 12.2(2)YC, 12.2(2)YC1, 12.2(2)YC2, 12.2(2)YC3, 12.2(2)YC4 | 12.2YH 12.2(4)YH | 12.2YJ 12.2(8)YJ, 12.2(8)YJ1 | 12.2YL 12.2(8)YL | 12.2YM 12.2(8)YM | 12.2YN 12.2(8)YN, 12.2(8)YN1 | 12.2YT 12.2(11)YT, 12.2(11)YT1, 12.2(11)YT2 | 12.2YU 12.2(11)YU | 12.2YV 12.2(11)YV | 12.2ZC 12.2(11)ZC, 12.2(13)ZC | 12.2ZD 12.2(13)ZD, 12.2(13)ZD1, 12.2(13)ZD2, 12.2(13)ZD3, 12.2(13)ZD4 | 12.2ZE 12.2(13)ZE | 12.2ZF 12.2(13)ZF, 12.2(13)ZF1, 12.2(13)ZF2 | 12.2ZH 12.2(13)ZH, 12.2(13)ZH10, 12.2(13)ZH2, 12.2(13)ZH3, 12.2(13)ZH4, 12.2(13)ZH5, 12.2(13)ZH6, 12.2(13)ZH7, 12.2(13)ZH8, 12.2(13)ZH9 | 12.2ZJ 12.2(15)ZJ, 12.2(15)ZJ1, 12.2(15)ZJ2, 12.2(15)ZJ3, 12.2(15)ZJ4, 12.2(15)ZJ5 | 12.2ZK 12.2(15)ZK, 12.2(15)ZK1, 12.2(15)ZK2, 12.2(15)ZK3, 12.2(15)ZK4, 12.2(15)ZK5, 12.2(15)ZK6 | 12.2ZL 12.2(15)ZL, 12.2(15)ZL1 | 12.2ZN 12.2(15)ZN | 12.2ZO 12.2(15)ZO | 12.2ZP 12.2(13)ZP, 12.2(13)ZP1, 12.2(13)ZP2, 12.2(13)ZP3, 12.2(13)ZP4 | 12.2ZR 12.2(15)ZR | 12.2ZS 12.2(15)ZS1, 12.2(15)ZS2, 12.2(15)ZS3, 12.2(15)ZS4, 12.2(15)ZS5 | 12.2ZT 12.2(13)ZT | 12.3 12.3(1), 12.3(1a), 12.3(3), 12.3(3a), 12.3(3b), 12.3(3c), 12.3(3d), 12.3(3e), 12.3(3f), 12.3(3g), 12.3(3h), 12.3(3i), 12.3(5), 12.3(5a), 12.3(5b), 12.3(5c), 12.3(5d), 12.3(5e), 12.3(5f), 12.3(6), 12.3(6a), 12.3(6b), 12.3(6c), 12.3(6d), 12.3(6e), 12.3(6f), 12.3(9), 12.3(9a), 12.3(9b), 12.3(9c), 12.3(9d), 12.3(9e), 12.3(10), 12.3(10a), 12.3(10b), 12.3(10c), 12.3(10d), 12.3(10e), 12.3(10f), 12.3(12), 12.3(12a), 12.3(12b), 12.3(12c), 12.3(12d), 12.3(12e), 12.3(13), 12.3(13a), 12.3(13b), 12.3(15), 12.3(15a), 12.3(15b), 12.3(16), 12.3(16a), 12.3(17), 12.3(17a), 12.3(17b), 12.3(17c), 12.3(18), 12.3(18a), 12.3(19), 12.3(19a), 12.3(20), 12.3(20a), 12.3(21), 12.3(21a), 12.3(21b), 12.3(22), 12.3(22a), 12.3(23), 12.3(24), 12.3(24a), 12.3(25), 12.3(26) | 12.3B 12.3(1a)B, 12.3(3)B, 12.3(3)B1, 12.3(5a)B, 12.3(5a)B0a, 12.3(5a)B1, 12.3(5a)B2, 12.3(5a)B3, 12.3(5a)B4, 12.3(5a)B5 | 12.3M 12.3(9)M0, 12.3(9)M1, 12.3(10a)M0 | 12.3T 12.3(2)T, 12.3(2)T1, 12.3(2)T2, 12.3(2)T3, 12.3(2)T4, 12.3(2)T5, 12.3(2)T6, 12.3(2)T7, 12.3(2)T8, 12.3(2)T9, 12.3(4)T, 12.3(4)T1, 12.3(4)T10, 12.3(4)T11, 12.3(4)T12, 12.3(4)T2, 12.3(4)T2a, 12.3(4)T3, 12.3(4)T4, 12.3(4)T5, 12.3(4)T6, 12.3(4)T7, 12.3(4)T8, 12.3(4)T9, 12.3(7)T, 12.3(7)T1, 12.3(7)T10, 12.3(7)T11, 12.3(7)T12, 12.3(7)T2, 12.3(7)T3, 12.3(7)T4, 12.3(7)T5, 12.3(7)T6, 12.3(7)T7, 12.3(7)T8, 12.3(7)T9, 12.3(8)T, 12.3(8)T1, 12.3(8)T10, 12.3(8)T11, 12.3(8)T2, 12.3(8)T3, 12.3(8)T4, 12.3(8)T5, 12.3(8)T6, 12.3(8)T7, 12.3(8)T8, 12.3(8)T9, 12.3(11)T, 12.3(11)T1, 12.3(11)T10, 12.3(11)T11, 12.3(11)T12, 12.3(11)T2, 12.3(11)T2a, 12.3(11)T3, 12.3(11)T4, 12.3(11)T5, 12.3(11)T6, 12.3(11)T7, 12.3(11)T8, 12.3(11)T9, 12.3(14)T, 12.3(14)T1, 12.3(14)T2, 12.3(14)T3, 12.3(14)T4, 12.3(14)T5, 12.3(14)T6, 12.3(14)T7 | 12.3TPC 12.3(4)TPC11b | 12.3XA 12.3(2)XA, 12.3(2)XA1, 12.3(2)XA4, 12.3(2)XA6 | 12.3XB 12.3(2)XB, 12.3(2)XB1, 12.3(2)XB3 | 12.3XC 12.3(2)XC, 12.3(2)XC1, 12.3(2)XC2, 12.3(2)XC3, 12.3(2)XC5 | 12.3XD 12.3(4)XD, 12.3(4)XD1, 12.3(4)XD2, 12.3(4)XD3, 12.3(4)XD4 | 12.3XE 12.3(2)XE, 12.3(2)XE1, 12.3(2)XE5 | 12.3XF 12.3(2)XF | 12.3XG 12.3(4)XG, 12.3(4)XG1, 12.3(4)XG2, 12.3(4)XG3, 12.3(4)XG4, 12.3(4)XG5 | 12.3XH 12.3(4)XH, 12.3(4)XH1 | 12.3XI 12.3(7)XI, 12.3(7)XI10a, 12.3(7)XI2, 12.3(7)XI2b, 12.3(7)XI3, 12.3(7)XI4, 12.3(7)XI5, 12.3(7)XI6, 12.3(7)XI7, 12.3(7)XI7a, 12.3(7)XI7b, 12.3(7)XI8, 12.3(7)XI8bc, 12.3(7)XI8g | 12.3XJ 12.3(7)XJ, 12.3(7)XJ1, 12.3(7)XJ2 | 12.3XK 12.3(4)XK, 12.3(4)XK1, 12.3(4)XK2, 12.3(4)XK3, 12.3(4)XK4 | 12.3XL 12.3(7)XL, 12.3(11)XL, 12.3(11)XL1, 12.3(11)XL2, 12.3(11)XL3 | 12.3XM 12.3(7)XM | 12.3XN 12.3(4)XN, 12.3(4)XN1, 12.3(4)XN2 | 12.3XQ 12.3(4)XQ, 12.3(4)XQ1 | 12.3XR 12.3(7)XR, 12.3(7)XR3, 12.3(7)XR4, 12.3(7)XR5, 12.3(7)XR6, 12.3(7)XR7 | 12.3XU 12.3(8)XU2, 12.3(8)XU3, 12.3(8)XU4, 12.3(8)XU5 | 12.3XW 12.3(8)XW, 12.3(8)XW1, 12.3(8)XW1a, 12.3(8)XW1b, 12.3(8)XW2, 12.3(8)XW3 | 12.3XX 12.3(8)XX, 12.3(8)XX1, 12.3(8)XX2d, 12.3(8)XX2e | 12.3XY 12.3(8)XY, 12.3(8)XY1, 12.3(8)XY2, 12.3(8)XY3, 12.3(8)XY4, 12.3(8)XY5, 12.3(8)XY6, 12.3(8)XY7 | 12.3XZ 12.3(2)XZ1, 12.3(2)XZ2 | 12.3YB 12.3(7)YB, 12.3(7)YB1 | 12.3YC 12.3(8)YC, 12.3(8)YC1, 12.3(8)YC2, 12.3(8)YC3 | 12.3YE 12.3(4)YE, 12.3(4)YE1 | 12.3YF 12.3(11)YF, 12.3(11)YF1, 12.3(11)YF2, 12.3(11)YF3, 12.3(11)YF4 | 12.3YG 12.3(8)YG, 12.3(8)YG2, 12.3(8)YG3, 12.3(8)YG4, 12.3(8)YG6 | 12.3YK 12.3(11)YK, 12.3(11)YK1, 12.3(11)YK2 | 12.3YL 12.3(11)YL, 12.3(11)YL1, 12.3(11)YL2 | 12.3YM 12.3(14)YM1, 12.3(14)YM10, 12.3(14)YM11, 12.3(14)YM12, 12.3(14)YM13, 12.3(14)YM2, 12.3(14)YM3, 12.3(14)YM4, 12.3(14)YM5, 12.3(14)YM6, 12.3(14)YM7, 12.3(14)YM8, 12.3(14)YM9 | 12.3YN 12.3(11)YN | 12.3YQ 12.3(14)YQ, 12.3(14)YQ1, 12.3(14)YQ2, 12.3(14)YQ3, 12.3(14)YQ4, 12.3(14)YQ5, 12.3(14)YQ6, 12.3(14)YQ7, 12.3(14)YQ8 | 12.3YR 12.3(11)YR, 12.3(11)YR1 | 12.3YS 12.3(11)YS2 | 12.3YT 12.3(14)YT, 12.3(14)YT1 | 12.3YU 12.3(14)YU, 12.3(14)YU1 | 12.3YX 12.3(14)YX, 12.3(14)YX1, 12.3(14)YX10, 12.3(14)YX11, 12.3(14)YX12, 12.3(14)YX13, 12.3(14)YX14, 12.3(14)YX15, 12.3(14)YX16, 12.3(14)YX17, 12.3(14)YX2, 12.3(14)YX3, 12.3(14)YX4, 12.3(14)YX7, 12.3(14)YX8, 12.3(14)YX9 | 12.3YZ 12.3(11)YZ, 12.3(11)YZ1, 12.3(11)YZ2 | 12.3ZA 12.3(8)ZA, 12.3(8)ZA1 | 12.3ZB 12.3(11)ZB, 12.3(11)ZB1, 12.3(11)ZB2 | 12.4 12.4(1), 12.4(1a), 12.4(1b), 12.4(1c), 12.4(3), 12.4(3a), 12.4(3b), 12.4(3c), 12.4(3d), 12.4(3e), 12.4(3f), 12.4(3g), 12.4(3h), 12.4(3i), 12.4(3j), 12.4(5), 12.4(5a), 12.4(5b), 12.4(5c), 12.4(7), 12.4(7a), 12.4(7b), 12.4(7c), 12.4(7d), 12.4(7e), 12.4(7f), 12.4(7g), 12.4(7h), 12.4(8), 12.4(8a), 12.4(8b), 12.4(8c), 12.4(8d), 12.4(10), 12.4(10a), 12.4(10b), 12.4(10c), 12.4(12), 12.4(12a), 12.4(12b), 12.4(12c), 12.4(13), 12.4(13a), 12.4(13b), 12.4(13c), 12.4(13d), 12.4(13e), 12.4(13f), 12.4(16), 12.4(16a), 12.4(16b), 12.4(17), 12.4(17a), 12.4(17b), 12.4(18), 12.4(18a), 12.4(18b), 12.4(18c), 12.4(18d), 12.4(18e), 12.4(19), 12.4(21), 12.4(21a), 12.4(23), 12.4(23a), 12.4(23b), 12.4(23c), 12.4(23d), 12.4(23e), 12.4(25), 12.4(25a), 12.4(25b), 12.4(25c), 12.4(25d), 12.4(25e), 12.4(25f) | 12.4GC 12.4(22)GC1, 12.4(22)GC1a, 12.4(24)GC1, 12.4(24)GC3, 12.4(24)GC3a, 12.4(24)GC4 | 12.4M 12.4(5a)M0, 12.4(21a)M1, 12.4(23b)M1 | 12.4MR 12.4(2)MR, 12.4(2)MR1, 12.4(4)MR, 12.4(4)MR1, 12.4(6)MR, 12.4(6)MR1, 12.4(9)MR, 12.4(11)MR, 12.4(12)MR, 12.4(12)MR1, 12.4(12)MR2, 12.4(16)MR, 12.4(16)MR1, 12.4(16)MR2, 12.4(19)MR, 12.4(19)MR1, 12.4(19)MR2, 12.4(20)MR, 12.4(20)MR2 | 12.4MRA 12.4(20)MRA, 12.4(20)MRA1 | 12.4MRB 12.4(20)MRB, 12.4(20)MRB1 | 12.4T 12.4(2)T, 12.4(2)T1, 12.4(2)T2, 12.4(2)T3, 12.4(2)T4, 12.4(2)T5, 12.4(2)T6, 12.4(4)T, 12.4(4)T1, 12.4(4)T2, 12.4(4)T3, 12.4(4)T4, 12.4(4)T5, 12.4(4)T6, 12.4(4)T7, 12.4(4)T8, 12.4(6)T, 12.4(6)T1, 12.4(6)T10, 12.4(6)T11, 12.4(6)T12, 12.4(6)T2, 12.4(6)T3, 12.4(6)T4, 12.4(6)T5, 12.4(6)T5a, 12.4(6)T5b, 12.4(6)T6, 12.4(6)T7, 12.4(6)T8, 12.4(6)T9, 12.4(9)T, 12.4(9)T0a, 12.4(9)T1, 12.4(9)T2, 12.4(9)T3, 12.4(9)T4, 12.4(9)T5, 12.4(9)T6, 12.4(9)T7, 12.4(11)T, 12.4(11)T1, 12.4(11)T2, 12.4(11)T3, 12.4(11)T4, 12.4(15)T, 12.4(15)T1, 12.4(15)T10, 12.4(15)T11, 12.4(15)T12, 12.4(15)T13, 12.4(15)T13b, 12.4(15)T14, 12.4(15)T15, 12.4(15)T16, 12.4(15)T2, 12.4(15)T3, 12.4(15)T4, 12.4(15)T5, 12.4(15)T6, 12.4(15)T6a, 12.4(15)T7, 12.4(15)T8, 12.4(15)T9, 12.4(20)T, 12.4(20)T1, 12.4(20)T2, 12.4(20)T3, 12.4(20)T4, 12.4(20)T5, 12.4(20)T5a, 12.4(20)T6, 12.4(22)T, 12.4(22)T1, 12.4(22)T2, 12.4(22)T3, 12.4(22)T4, 12.4(22)T5, 12.4(24)T, 12.4(24)T1, 12.4(24)T2, 12.4(24)T3, 12.4(24)T4, 12.4(24)T5, 12.4(24)T6 | 12.4XA 12.4(2)XA, 12.4(2)XA1, 12.4(2)XA2 | 12.4XB 12.4(2)XB, 12.4(2)XB1, 12.4(2)XB10, 12.4(2)XB11, 12.4(2)XB2, 12.4(2)XB3, 12.4(2)XB4, 12.4(2)XB5, 12.4(2)XB6, 12.4(2)XB7, 12.4(2)XB8, 12.4(2)XB9 | 12.4XC 12.4(4)XC, 12.4(4)XC1, 12.4(4)XC2, 12.4(4)XC3, 12.4(4)XC4, 12.4(4)XC5, 12.4(4)XC6, 12.4(4)XC7 | 12.4XD 12.4(4)XD, 12.4(4)XD1, 12.4(4)XD10, 12.4(4)XD11, 12.4(4)XD12, 12.4(4)XD2, 12.4(4)XD3, 12.4(4)XD4, 12.4(4)XD5, 12.4(4)XD6, 12.4(4)XD7, 12.4(4)XD8, 12.4(4)XD9 | 12.4XE 12.4(6)XE, 12.4(6)XE1, 12.4(6)XE2, 12.4(6)XE3 | 12.4XG 12.4(9)XG2 | 12.4XJ 12.4(11)XJ, 12.4(11)XJ1, 12.4(11)XJ2, 12.4(11)XJ3, 12.4(11)XJ4, 12.4(11)XJ5, 12.4(11)XJ6 | 12.4XL 12.4(15)XL, 12.4(15)XL1, 12.4(15)XL2, 12.4(15)XL3, 12.4(15)XL4, 12.4(15)XL5 | 12.4XM 12.4(15)XM1, 12.4(15)XM2 | 12.4XP 12.4(6)XP | 12.4XT 12.4(6)XT, 12.4(6)XT1, 12.4(6)XT2 | 12.4XV 12.4(11)XV, 12.4(11)XV1 | 12.4XW 12.4(11)XW, 12.4(11)XW1, 12.4(11)XW10, 12.4(11)XW2, 12.4(11)XW3, 12.4(11)XW4, 12.4(11)XW5, 12.4(11)XW6, 12.4(11)XW7, 12.4(11)XW8, 12.4(11)XW9 | 12.4XY 12.4(15)XY, 12.4(15)XY1, 12.4(15)XY2, 12.4(15)XY3, 12.4(15)XY4, 12.4(15)XY5 | 12.4XZ 12.4(15)XZ, 12.4(15)XZ1, 12.4(15)XZ2 | 12.4YA 12.4(20)YA, 12.4(20)YA1, 12.4(20)YA2, 12.4(20)YA3 | 12.4YB 12.4(22)YB, 12.4(22)YB1, 12.4(22)YB4, 12.4(22)YB5, 12.4(22)YB6, 12.4(22)YB7, 12.4(22)YB8 | 15.0M 15.0(1)M, 15.0(1)M1, 15.0(1)M2, 15.0(1)M3, 15.0(1)M4, 15.0(1)M5, 15.0(1)M6, 15.0(1)M7 | 15.0XA 15.0(1)XA, 15.0(1)XA1, 15.0(1)XA2, 15.0(1)XA3, 15.0(1)XA4, 15.0(1)XA5 | 15.1GC 15.1(2)GC, 15.1(2)GC1 | 15.1T 15.1(1)T, 15.1(1)T1, 15.1(1)T2, 15.1(1)T3, 15.1(2)T, 15.1(2)T0a, 15.1(2)T1, 15.1(2)T2, 15.1(2)T2a, 15.1(2)T3, 15.1(2)T4, 15.1(3)T, 15.1(3)T1 | 15.1XB 15.1(1)XB, 15.1(1)XB1, 15.1(1)XB2, 15.1(1)XB3

Associated Products:
N/A




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