Security Intelligence Operations

IPS signature event data from Cisco Remote Management Services is available for IPS signatures from July 10, 2008.

Contents

Introduction

Microsoft announced seven security bulletins that contain ten vulnerabilities as part of the monthly security bulletin release on June 10, 2008. A summary of these bulletins is on the Microsoft website at http://www.microsoft.com/technet/security/bulletin/ms08-jun.mspx. This document highlights the vulnerabilities that can be effectively identified and/or mitigated using Cisco network devices.

The vulnerabilities that have a client software attack vector, require user interaction, or can be exploited through web-based attacks such as cross-site scripting or phishing are in the following list:

• MS08-031
• MS08-033
• MS08-034

MS08-030, Vulnerability in Bluetooth Stack Could Allow Remote Code Execution (951376), is exploited through the Bluetooth protocol, which is a short-range wireless protocol that does not transit network infrastructure equipment.

The vulnerabilities that have a network mitigation are in the following list. Cisco devices provide several countermeasures for the vulnerabilities that have a network attack vector, which will be discussed in detail later in this document.

• MS08-032
• MS08-035
• MS08-036

Information about affected and unaffected products is available in the respective Microsoft advisories and the IntelliShield alerts that are referenced in the following table. In addition, multiple Cisco products use Microsoft operating systems as their base operating system. Cisco products that may be affected by the vulnerabilities described in the referenced Microsoft advisories are detailed in the "Associated Products" table in the "Product Sets" section.

Vulnerability Characteristics

Three of the Microsoft Security Bulletins will be covered in this Applied Mitigation Bulletin. The following vulnerabilities are summarized in this document:

MS08-036, Vulnerabilities in Pragmatic General Multicast (PGM) Could Allow Denial of Service (950762): These vulnerabilities have been assigned CVE identifiers CVE-2008-1440 and CVE-2008-1441. These vulnerabilities can be exploited remotely without authentication and without end-user interaction.

Successful exploitation of the vulnerability for CVE-2008-1440 and CVE-2008-1441 may result in a denial of service (DoS) condition. The attack vector for exploitation of CVE-2008-1440 and CVE-2008-1441 is through the Pragmatic General Multicast (PGM) protocol which can be transported over IP protocol number 113. An attacker could exploit this vulnerability using spoofed packets.

Note: PGM is enabled only when Microsoft Message Queuing (MSMQ) 3.0 or 4.0 are installed. Microsoft Message Queuing (MSMQ) is not installed by default.

MS08-035,Vulnerability in Active Directory Could Allow Denial of Service (953235): This vulnerability has been assigned CVE identifier CVE-2008-1445. This vulnerability can be exploited remotely with authentication and without user interaction. Successful exploitation of this vulnerability may result in a DoS condition. The attack vector is through the following protocols:

• LDAP protocol using TCP port 389
• LDAPS protocol using TCP port 636
• Microsoft Global Catalog protocol using TCP port 3268
• Microsoft Global Catalog SSL protocol using TCP port 3269

MS08-032, Cumulative Security Update of ActiveX Kill Bits (950760): This vulnerability has been assigned CVE Identifier CVE-2007-0675. This vulnerability can be exploited remotely without authentication and requires user interaction. Successful exploitation of this vulnerability may allow arbitrary code execution. Cross-site scripting and phishing could be used to exploit this vulnerability. For additional information about cross-site scripting attacks and the methods used to exploit these vulnerabilities, refer to the Cisco Applied Mitigation Bulletin Understanding Cross-Site Scripting (XSS) Threat Vectors. The attack vector for exploitation of this vulnerability is through HTTP packets, which typically use the following ports:

• TCP port 80
• TCP port 3128
• TCP port 8000
• TCP port 8010
• TCP port 8080
• TCP port 8888
• TCP port 24326

Information about vulnerable, unaffected, and fixed software is available in the Microsoft Security Bulletin Summary for June 2008, which is available at the following link: http://www.microsoft.com/technet/security/bulletin/ms08-jun.mspx

Mitigation Technique Overview

The vulnerabilities that have a client software attack vector, require user interaction, or can be exploited through web-based attacks such as cross-site scripting or phishing are in the following list:

• MS08-031
• MS08-033
• MS08-034

MS08-030, Vulnerability in Bluetooth Stack Could Allow Remote Code Execution (951376), is exploited through the Bluetooth protocol, which is a short-range wireless protocol that does not transit network infrastructure equipment.

These vulnerabilities are best mitigated at the endpoint through software updates, user education, desktop administration best practices, and endpoint protection software such as Cisco Security Agent Host Intrusion Prevention System (HIPS) or antivirus products.

The vulnerabilities that have a network mitigation are in the following list. Cisco devices provide several countermeasures for these vulnerabilities. This section of the document provides an overview of these techniques.

• MS08-032
• MS08-035
• MS08-036

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

• Transit access control lists (tACLs)
• Unicast Reverse Path Forwarding (Unicast RPF)
• 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 the vulnerabilities that have a network attack vector.

The proper deployment and configuration of Unicast RPF provides an effective means of protection against attacks that use packets with spoofed source IP addresses. Unicast RPF 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 spoofed packets at the access layer.

Because the potential exists that a trusted networking client could become affected by a worm that does not use packets with spoofed source addresses, Unicast RPF and IPSG do not provide complete protection against these vulnerabilities.

Effective means of exploit prevention can also be provided by Cisco ASA 5500 Series Adaptive Security Appliance, Cisco PIX 500 Series Security Appliance, and the Firewall Services Module (FWSM) for Cisco Catalyst 6500 Series switches and Cisco 7600 Series routers using the following:

• tACLs
• Application layer protocol inspection
• Unicast Reverse Path Forwarding (Unicast RPF)
• Filtering ActiveX objects

These protection mechanisms filter and drop, as well as verify the source IP address of, packets that are attempting to exploit the vulnerabilities that have a network attack vector.

Effective use of Cisco Intrusion Prevention System (IPS) event actions provides visibility into and protection against attacks that attempt to exploit these vulnerabilities as discussed later in this document.

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

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

The Cisco Security Monitoring, Analysis, and Response System (Cisco Security MARS) appliance 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 these vulnerabilities. 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
• Cisco IOS NetFlow
• Cisco ASA, PIX, and FWSM Firewalls
• Cisco Intrusion Prevention System
• Cisco Security Monitoring, Analysis, and Response System

Cisco IOS Routers and Switches

Mitigation: Transit Access Control Lists

MS08-036, Vulnerabilities in Pragmatic General Multicast (PGM) Could Allow Denial of Service (950762)

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 these vulnerabilities that have a network attack vector when the attack comes from a trusted source address.

The tACL policy denies unauthorized PGM packets (IP Protocol 113) 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. Because PGM should be sent to multicast addresses on local segments and may be sent between segments to unicast IP addresses, filtering on the affected destination network address (which is 192.168.60.0/24) is not sufficient. Therefore, filtering for any destination network will, in effect, block multicast and unicast destinations. It should be noted that multicast addresses will not be routed unless the router is specifically configured to do so. Care should be taken to allow required traffic for routing and administrative access prior to denying all unauthorized traffic.

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

!-- Include any explicit permit statements for trusted sources
!-- that require access on the vulnerable protocol
!
access-list 150 permit 113 host 192.168.100.1 any 
!
!-- The following vulnerability-specific access control entries
!-- (ACEs) can aid in identification of attacks
!
access-list 150 deny 113 any any
!
!-- Permit/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
!
!-- Apply tACL to interfaces in the ingress direction
interface GigabitEthernet0/0
 ip access-group 150 in
!

MS08-035,Vulnerability in Active Directory Could Allow Denial of Service (953235)

The tACL policy denies unauthorized LDAP packets on TCP port 389, LDAP over TLS/SSL packets on TCP port 636, Microsoft Global Catalog packets on TCP port 3268, and Microsoft Global Catalog with LDAP/SSL packets on TCP port 3269 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.

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

!-- Include any explicit permit statements for trusted sources
!-- that require access on the vulnerable ports
!
access-list 150 permit tcp host 192.168.100.1 192.168.60.0 0.0.0.255 eq 389
access-list 150 permit tcp host 192.168.100.1 192.168.60.0 0.0.0.255 eq 3268
access-list 150 permit tcp host 192.168.100.1 192.168.60.0 0.0.0.255 eq 636
access-list 150 permit tcp host 192.168.100.1 192.168.60.0 0.0.0.255 eq 3269
!
!-- 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 389
access-list 150 deny tcp any 192.168.60.0 0.0.0.255 eq 3268
access-list 150 deny tcp any 192.168.60.0 0.0.0.255 eq 636
access-list 150 deny tcp any 192.168.60.0 0.0.0.255 eq 3269
!
!-- Permit/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
!
!-- Apply tACL to interfaces in the ingress direction
interface GigabitEthernet0/0
 ip access-group 150 in
!

Note: 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.

Mitigation: Spoofing Protection

Unicast Reverse Path Forwarding

MS08-036 has a network attack vector and can be exploited by spoofed IP packets. The proper deployment and configuration of Unicast Reverse Path Forwarding (Unicast RPF) can provide protection mechanisms for spoofing.

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

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

For additional information about the configuration and use of Unicast RPF, reference the Understanding Unicast Reverse Path Forwarding Applied Intelligence 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. The proper deployment and configuration of IPSG coupled with strict mode Unicast RPF can provide the most effective means of spoofing protection to help mitigate MS08-036.

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

Identification: Transit Access Control Lists

MS08-036, Vulnerabilities in Pragmatic General Multicast (PGM) Could Allow Denial of Service (950762)

After the administrator applies the tACL to an interface, the show ip access-lists command will identify the number of PGM packets that have been filtered. Administrators are advised to investigate filtered packets to determine whether they are attempts to exploit these vulnerabilities. Example output for show ip access-lists 150 follows:

router#show ip access-lists 150
Extended IP access list 150
    10 permit 113 host 192.168.100.1 any
    20 deny 113 any any (12 matches)
    30 deny ip any any
router#

In the preceding example, access list 150 has dropped 12 PGM packets (IP Protocol 113) for ACE line 20.

MS08-035,Vulnerability in Active Directory Could Allow Denial of Service (953235)

After the administrator applies the tACL to an interface, the show ip access-lists command will identify the number of LDAP packets on TCP port 389, Microsoft Global Catalog packets on TCP port 3268, LDAP over TLS/SSL packets on TCP port 636, and Microsoft Global Catalog with LDAP/SSL packets on TCP port 3269 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 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 389 (1065 matches)
    20 permit tcp host 192.168.100.1 192.168.60.0 0.0.0.255 eq 3268 (999 matches)
    30 permit tcp host 192.168.100.1 192.168.60.0 0.0.0.255 eq 636 (19 matches)
    40 permit tcp host 192.168.100.1 192.168.60.0 0.0.0.255 eq 3269 (43 matches)
    50 deny tcp any 192.168.60.0 0.0.0.255 eq 389 (268 matches)
    60 deny tcp any 192.168.60.0 0.0.0.255 eq 3268 (138 matches)
    70 deny tcp any 192.168.60.0 0.0.0.255 eq 636 (17 matches)
    80 deny tcp any 192.168.60.0 0.0.0.255 eq 3269 (37 matches)
    90 deny ip any any
router#

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

• 268 LDAP packets on TCP port 389 for ACE line 50
• 138 Microsoft Global Catalog packets on TCP port 3268 for ACE line 60
• 17 LDAP over TLS/SSL packets on TCP port 636 for ACE line 70
• 37 Microsoft Global Catalog with LDAP/SSL packets on TCP port 3269 for ACE line 80

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.

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 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 Applied Intelligence white paper.

Identification: Spoofing Protection Using Unicast Reverse Path Forwarding

With Unicast RPF 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, and show ip traffic commands to identify the number of packets that Unicast RPF has dropped.

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 available in the show command sections of the Cisco IOS Configuration Fundamentals Command Reference.

router#show cef interface GigabitEthernet 0/0 internal | include drop 

-- CLI Output Truncated --

ip verify: via=rx (allow default), acl=0, drop=27, 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

    --      CLI Output Truncated       --
  ip verify: via=rx (allow default), acl=0, drop=2128, sdrop=0
router#


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



router#show ip traffic
IP statistics:
  Rcvd:  44752535 total, 31742185 local destination
         0 format errors, 0 checksum errors, 36257 bad hop count
         0 unknown protocol, 18 not a gateway
         0 security failures, 0 bad options, 8624 with options
  Opts:  0 end, 0 nop, 0 basic security, 0 loose source route
         0 timestamp, 0 extended security, 0 record route
         0 stream ID, 0 strict source route, 8624 alert, 0 cipso, 0 ump
         0 other
  Frags: 0 reassembled, 0 timeouts, 0 couldn't reassemble
         0 fragmented, 0 fragments, 0 couldn't fragment
  Bcast: 28583 received, 0 sent
  Mcast: 470705 
received, 1183004 sent
  Sent:  
32428132 generated, 12967733 forwarded
  Drop:  62687 encapsulation failed, 0 unresolved, 0 no adjacency
         27 no route, 27 unicast RPF, 0 forced 
drop
         0 options denied
  Drop:  0 packets with source IP address zero
  Drop:  0 packets with internal loop back IP address
         0 physical broadcast
        --      CLI Output Truncated       --

router#  

In the preceding show cef drop and show ip traffic examples, Unicast RPF has dropped 27 IP packets received globally on all interfaces with Unicast RPF configured because of the inability to verify the source address of the IP packets within the Cisco Express Forwarding Forwarding Information Base.

Cisco IOS NetFlow

Identification: Traffic Flow Identification Using NetFlow Records

Administrators can configure Cisco IOS NetFlow on Cisco IOS routers and switches to aid in the identification of traffic flows that may be attempts to exploit the vulnerabilities described in this document that have a network attack vector. Administrators are advised to investigate flows to determine whether they are attempts to exploit the vulnerabilities or whether they are legitimate traffic flows.

router#show ip cache flow 
IP packet size distribution (154484930 total packets):
   1-32   64   96  128  160  192  224  256  288  320  352  384  416  448  480
   .000 .403 .093 .015 .030 .025 .018 .004 .011 .001 .003 .002 .002 .005 .007

    512  544  576 1024 1536 2048 2560 3072 3584 4096 4608
   .016 .002 .212 .067 .074 .000 .000 .000 .000 .000 .000

IP Flow Switching Cache, 4456704 bytes
  307 active, 65229 inactive, 7713523 added
  144439048 ager polls, 0 flow alloc failures
  Active flows timeout in 2 minutes
  Inactive flows timeout in 60 seconds
IP Sub Flow Cache, 336520 bytes
  0 active, 16384 inactive, 3108972 added, 3108972 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       14414      0.0        29    45      0.1       9.2      30.8
TCP-FTP            760      0.0         9    58      0.0      25.1      21.2
TCP-FTPD           262      0.0      2362   493      0.1      15.1      21.0
TCP-WWW          73766      0.0        14   539      0.2      10.5      38.8
TCP-SMTP          1486      0.0         7   129      0.0       7.2      10.4
TCP-X                4      0.0         1    46      0.0       0.0      60.6
TCP-BGP           1688      0.0         3    44      0.0      13.9      60.6
TCP-NNTP             4      0.0         1    46      0.0       0.0      60.5
TCP-other      5757793      1.3        24   325     32.9       2.3       7.0
UDP-DNS          93928      0.0         5    72      0.1      38.6      43.1
UDP-NTP         463761      0.1         1    76      0.1       5.4      58.3
UDP-TFTP           435      0.0         1    77      0.0       0.5      59.3
UDP-Frag        301039      0.0         6   569      0.4       0.0      15.6
UDP-other       903059      0.2         8   385      1.7       8.4      22.2
ICMP             95611      0.0         3   121      0.0      21.2      54.3
IPINIP               1      0.0         2    20      0.0       0.1      60.1
IPv6INIP             8      0.0         5   104      0.0       0.3      60.6
GRE               4942      0.0        47    52      0.0     119.6       0.8
IP-other           228      0.0         5   121      0.0      32.6      44.8
Total:         7713189      1.7        20   329     35.9       3.9      13.6

SrcIf         SrcIPaddress    DstIf         DstIPaddress    Pr SrcP DstP  Pkts
Gi0/0         192.168.208.63  Gi0/1         192.168.60.6    06 9A37 0185     1 
Gi0/0         192.168.208.63  Gi0/1         192.168.60.6    06 9A38 0CC4     1 
Gi0/0         192.18.104.132  Gi0/1         192.168.150.60  06 1A29 94E5     1 
Gi0/0         192.18.104.132  Gi0/1         192.168.150.60  06 1A29 94E4     1  
Gi0/0         198.18.9.66     Gi0/1         192.168.200.20  06 1291 04C2     3 
Gi0/0         198.18.9.66     Gi0/1         192.168.200.20  06 12AE 04C2     2 
Gi0/0         198.18.59.6     Gi0/1         192.168.200.20  06 12AC 04C2     3 
Gi0/0         192.168.28.13   Local         192.168.206.20  06 9389 0016    69 
Gi0/0         192.168.208.63  Gi0/1         192.168.150.60  06 F87A F879     1 
Gi0/0         192.168.208.63  Gi0/1         192.168.150.60  06 F879 F879     1 
Gi0/0         192.168.208.64  Null          192.168.208.255 11 0089 0089     3 
Gi0/0         192.168.208.63  Gi0/1         192.168.206.40  01 0000 0303    15 
Gi0/0         192.168.208.63  Gi0/1         224.0.0.44      71 3A05 0DC8     2 
Gi0/0         192.168.208.63  Gi0/1         224.0.0.44      71 20A7 0DC7     2 
Gi0/0         192.168.208.63  Gi0/1         224.0.0.44      71 3A49 0DC7     2 

In the preceding example, there are multiple flows for PGM packets using IP protocol 113 (hex value 0071), for LDAP on TCP port 389 (hex value 0185), and for Microsoft Global Catalog on TCP port 3268 (hex value 0CC4) . This traffic is 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 the vulnerabilities described in this document that have a network attack vector. Administrators are advised to compare these flows to baseline utilization for these Protocols and also investigate the flows to determine whether they are sourced from untrusted hosts or networks.

To view only the traffic flows for LDAP packets on TCP port 389 (hex value 0185), LDAP over TLS/SSL packets on TCP port 636 (hex value 027C), Microsoft Global Catalog packets on TCP port 3268 (hex value 0CC4), and Microsoft Global Catalog with LDAP/SSL packets on TCP port 3269 (hex value 0CC5, the command show ip cache flow | include SrcIf|_06_.*(0185|027C|0CC4|0CC5)_ will display the related TCP NetFlow records as shown here:

TCP Flows

router#show ip cache flow | include SrcIf|_06_.*(0185|027F|0CC4|0CC5)_
SrcIf         SrcIPaddress    DstIf         DstIPaddress    Pr SrcP DstP  Pkts
Gi0/0         192.168.208.63  Gi0/1         192.168.60.62   06 9A46 0185     1 
Gi0/0         192.168.208.63  Gi0/1         192.168.60.63   06 9A49 0CC4     1 
Gi0/0         192.168.208.63  Gi0/1         192.168.60.63   06 9A48 0CC5     1 
router#  

To view only the traffic flows for PGM packets on IP Protocol 113 (hex value 0071), the command show ip cache flow | include SrcIf|_71_ will display the related PGM NetFlow records as shown here:

PGM Flows

router#show ip cache flow | include SrcIf|_71_
SrcIf         SrcIPaddress    DstIf         DstIPaddress    Pr SrcP DstP  Pkts
Gi0/0         192.168.208.63  Gi0/1         224.0.0.44      71 20A7 0DC7     2 
Gi0/0         192.168.208.63  Gi0/1         224.0.0.44      71 3A49 0DC7     2 

Cisco ASA, PIX, and FWSM Firewalls

Mitigation: Transit Access Control Lists

MS08-036, Vulnerabilities in Pragmatic General Multicast (PGM) Could Allow Denial of Service (950762)

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 the vulnerabilities that have a network attack vector when the attack comes from a trusted source address.

The tACL policy denies unauthorized PGM packets on IP Protocol 113 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. Because PGM should be sent to multicast addresses on local segments and may be sent between segments to unicast IP addresses, filtering on the affected destination network address (which is 192.168.60.0/24) is not sufficient. Therefore, filtering for any destination network will, in effect, block multicast and unicast destinations. However the Cisco ASA, PIX, and FWSM firewalls will block multicast destination addresses by default unless they are specifically configured to forward multicast traffic. Care should be taken to allow required traffic for routing and administrative access prior to denying all unauthorized traffic.

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

!
!-- Include any explicit permit statements for trusted sources
!-- that require access on the vulnerable protocol
!
access-list Transit-ACL-Policy extended permit 113 host 
            192.168.100.1 any 
!
!-- The following vulnerability-specific access control entries
!-- (ACEs) can aid in identification of attacks
!
access-list Transit-ACL-Policy extended deny 113 any 
            any 
!
!-- Permit/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 Transit-ACL-Policy extended deny ip any any
!
!-- Apply tACL to interface(s) in the ingress direction
!
access-group Transit-ACL-Policy in interface outside
!

MS08-035,Vulnerability in Active Directory Could Allow Denial of Service (953235)

The tACL policy denies unauthorized LDAP packets on TCP port 389 (ldap), LDAP over TLS/SSL packets on TCP port 636, Microsoft Global Catalog packets on TCP port 3268, and Microsoft Global Catalog with LDAP/SSL packets on TCP port 3269 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.

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

!
!-- Include any explicit permit statements for trusted sources
!-- that require access on the vulnerable ports
!
access-list Transit-ACL-Policy extended permit tcp host 192.168.100.1 
            192.168.60.0 255.255.255.0 eq ldap
access-list Transit-ACL-Policy extended permit tcp host 192.168.100.1 
            192.168.60.0 255.255.255.0 eq 3268
access-list Transit-ACL-Policy extended permit tcp host 192.168.100.1 
            192.168.60.0 255.255.255.0 eq ldaps
access-list Transit-ACL-Policy extended permit tcp host 192.168.100.1 
            192.168.60.0 255.255.255.0 eq 3269
!
!-- The following vulnerability-specific access control entries
!-- (ACEs) can aid in identification of attacks
!
access-list Transit-ACL-Policy extended deny tcp any 192.168.60.0 
            255.255.255.0 eq ldap
access-list Transit-ACL-Policy extended deny tcp any 192.168.60.0 
            255.255.255.0 eq 3268
access-list Transit-ACL-Policy extended deny tcp any 192.168.60.0 
            255.255.255.0 eq ldaps
access-list Transit-ACL-Policy extended deny tcp any 192.168.60.0 
            255.255.255.0 eq 3269
!
!-- Permit/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 Transit-ACL-Policy extended deny ip any any
!
!-- Apply tACL to interface(s) in the ingress direction
!
access-group Transit-ACL-Policy in interface outside
!
 

Mitigation: Application Layer Protocol Inspection

MS08-032, Cumulative Security Update of ActiveX Kill Bits (950760)

Application layer protocol inspection is available beginning in software release 7.0 for the Cisco ASA 5500 Series Adaptive Security Appliance or the Cisco PIX 500 Series Security Appliance and in software release 3.1 for the Firewall Services Module. This advanced security feature performs deep packet inspection of traffic that is transiting through the firewall. Administrators may construct an inspection policy for applications that require special handling through the configuration of inspect class maps and inspect policy maps, which are applied via a global or interface service policy.

HTTP Inspection

Using the HTTP inspection engine on Cisco ASA 5500 Series Adaptive Security Appliances and Cisco PIX 500 Series Security Appliances, administrators can configure regular expressions for pattern matching, inspection class maps, and inspection policy maps that can protect against specific attacks such as MS08-032 and other threats that may be associated with HTTP traffic. The following HTTP inspection uses the Modular Policy Framework (MPF) to create a policy for inspection of traffic on TCP ports 80, 3128, 8000, 8010, 8080, 8888, and 24326, which are the default Cisco IPS WEBPORTS. The HTTP inspection policy will drop connections where the HTTP response body contains any of the two regular expressions that are configured to match the two ActiveX controls defined in MS08-032.

Additional information about application layer protocol inspection is available in Configuring Application Layer Protocol Inspection.

Caution: The configured regular expressions will match on any text strings in the body of an HTML response. Care should be taken to ensure that legitimate business applications that use matching text strings without calling the ActiveX control are not impacted.

Caution: Application layer protocol inspection will decrease firewall performance. Performance impact should be tested in a lab environment before deployment in production environments.

Note: The Firewall Services Module versions 3.1 and 3.2 do not support the regular expression capabilities necessary to perform the following application inspection. Instead, administrators may use filtering services as described later in this document in "Filtering ActiveX Objects."

This MPF policy inspects all HTTP traffic and will apply the configured actions and parameters:

! 
! Configure regular expressions for the ActiveX controls:
! 47206204-5eca-11d2-960f-00c04f8ee628, 
! 3b224890-4fe9-4a37-8c1e-5e7e12791c1f, 
! defined in MS08-032
!
regex CLSID_activeX1 "47206204[-]5[eE][cC][aA][-]11[dD]2[-]960[fF][-]00[cC]
      04[fF]8[eE][eE]628"
regex CLSID_activeX2 "3[bB]224890[-]4[fF][eE]9[-]4[aA]37[-]8[cC]1[eE][-]5[eE]7[eE]
      12791[cC]1[fF]"
! 
! Configure a regex class to match on the regular expressions configured above
!

class-map type regex match-any regex-class
 match regex CLSID_activeX1
 match regex CLSID_activeX2
!
! Configure an HTTP inspection class to search HTTP response bodies
! for the regular expressions contained in the regex class above
!
class-map type inspect http match-all http-class
 match response body regex class regex-class
!
! Configure an object group for the default Cisco IPS #WEBPORTS, which
! are TCP ports 80 (www), 3128, 8000, 8010, 8080, 8888, and 24326
!
object-group service WEBPORTS
 service-object tcp eq www 
 service-object tcp eq 3128 
 service-object tcp eq 8000 
 service-object tcp eq 8010 
 service-object tcp eq 8080 
 service-object tcp eq 8888 
 service-object tcp eq 24326 

!
! Configure an access list, using the WEBPORTS object group,
! which will be used to match TCP packets destined to #WEBPORTS
!
access-list WEBPORTS extended permit object-group WEBPORTS any any 
!
! Configure a class that uses the above-configured access list to
! match TCP packets destined to Cisco IPS #WEBPORTS, which are
! TCP ports 80 (www), 3128, 8000, 8010, 8080, 8888, and 24326
!
class-map webports
 match access-list WEBPORTS
!
! Configure an HTTP inspection policy that looks for and drops connections
! containing HTTP protocol violations and looks for and drops connections 
! that contain any of the two regular expressions for the two affected 
! ActiveX controls configured above
! 
policy-map type inspect http http-policy
 parameters
!
! protocol-violation below is not required to mitigate MS08-032,
! but is included to provide more robust protection against
! potential HTTP attacks. Care should be taken to ensure that
! legitimate applications that do not fully conform to HTTP 
! protocol standards are not dropped by this inspection.
!
  protocol-violation action drop-connection
 class http-class
  drop-connection log
!
! Add the above-configured class webports that match 
! TCP packets destined to default Cisco IPS #WEBPORTS 
! to the default policy global_policy and use it to
! inspect HTTP traffic transiting the firewall
! 

policy-map global_policy
 class webports
  inspect http http-policy 
!
! By default, the policy global_policy is applied globally, resulting in
! inspection of traffic entering the firewall from all interfaces 
!
service-policy global_policy global
  

Mitigation: Spoofing Protection Using Unicast Reverse Path Forwarding

MS08-036 has a network attack vector and can be exploited by spoofed IP packets. The proper deployment and configuration of Unicast Reverse Path Forwarding (Unicast RPF) can provide protection mechanisms for spoofing.

Unicast RPF is configured at the interface level and can detect and drop packets that lack a verifiable source IP address. Administrators should not rely on Unicast RPF to provide complete spoofing protection because spoofed packets may enter the network through a Unicast RPF-enabled interface if an appropriate return route to the source IP address exists. In an enterprise environment, Unicast RPF might 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 Unicast RPF, reference the Cisco Security Appliance Command Reference for ip verify reverse-path and the Understanding Unicast Reverse Path Forwarding Applied Intelligence white paper.

Mitigation: Filtering ActiveX Objects

MS08-032, Cumulative Security Update of ActiveX Kill Bits (950760)

To protect the network from malicious ActiveX objects that enter the network at ingress access points, which may include Internet connection points, partner and supplier connection points, or VPN connection points, administrators may deploy ActiveX filtering using the filter activex command. This command filters HTML object tags and replaces the tags with comments. Filtering applies only when the connection that is requesting the object originates from a higher security level interface (for example, the Inside interface) and the object to be filtered enters the firewall from a lower security level interface (for example, the Outside interface).

Caution: This command will also filter Java applets, image files, and multimedia objects that are embedded within object tags in HTML pages. This command will not filter HTML object tags that are split across packets.

In the following example, all source and destination IP addresses will be filtered on TCP ports 80, 3128, 8000, 8010, 8080, 8888, and 24326. HTML traffic that is encrypted using SSL or TLS can not be filtered by this feature.

More information is available in Applying Filtering Services.

!-- Filter ActiveX from all sources to all destinations on
!-- TCP ports 80, 3128, 8000, 8010, 8080, 8088, and 24326
!
filter activex 80 0 0 0 0
filter activex 3128 0 0 0 0
filter activex 8000 0 0 0 0
filter activex 8010 0 0 0 0
filter activex 8080 0 0 0 0
filter activex 8888 0 0 0 0
filter activex 24326 0 0 0 0
!

Identification: Transit Access Control Lists

MS08-036, Vulnerabilities in Pragmatic General Multicast (PGM) Could Allow Denial of Service (950762)

After the tACL has been applied to an interface, administrators can use the show access-list command to identify the number of PGM packets (IP Protocol 113) that have been filtered. Administrators are advised to investigate filtered packets to determine whether they are attempts to exploit these vulnerabilities. Example output for show access-list Transit-ACL-Policy follows:

firewall#show access-list Transit-ACL-Policy
access-list Transit-ACL-Policy; 3 elements
access-list Transit-ACL-Policy line 1 extended permit 113 
            host 192.168.100.1 any (hitcnt=0)
access-list Transit-ACL-Policy line 2 extended deny 113 any 
            any (hitcnt=89)
access-list Transit-ACL-Policy line 3 extended deny ip any any (hitcnt=406)
firewall#

In the preceding example, access list Transit-ACL-Policy has dropped 89 packets on IP Protocol 113 (PGM) received from an untrusted host or network.

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.

MS08-035,Vulnerability in Active Directory Could Allow Denial of Service (953235)

After the tACL has been applied to an interface, administrators can use the show access-list command to identify the number of LDAP packets on TCP port 389 (ldap), Microsoft Global Catalog packets on TCP port 3268, LDAP over TLS/SSL packets on TCP port 636 (ldaps), and Microsoft Global Catalog with LDAP/SSL packets on TCP port 3269 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 Transit-ACL-Policy follows:

firewall#show access-list Transit-ACL-Policy
access-list Transit-ACL-Policy; 9 elements
access-list Transit-ACL-Policy line 1 extended permit tcp host 192.168.100.1 
            192.168.60.0 255.255.255.0 eq ldap (hitcnt=5) 
access-list Transit-ACL-Policy line 2 extended permit tcp host 192.168.100.1 
            192.168.60.0 255.255.255.0 eq 3268 (hitcnt=3) 
access-list Transit-ACL-Policy line 3 extended permit tcp host 192.168.100.1 
            192.168.60.0 255.255.255.0 eq ldaps (hitcnt=4) 
access-list Transit-ACL-Policy line 4 extended permit tcp host 192.168.100.1 
            192.168.60.0 255.255.255.0 eq 3269 (hitcnt=8) 
access-list Transit-ACL-Policy line 5 extended deny tcp any 192.168.60.0 
            255.255.255.0 eq ldap (hitcnt=23)
access-list Transit-ACL-Policy line 6 extended deny tcp any 192.168.60.0 
            255.255.255.0 eq 3268 (hitcnt=19)
access-list Transit-ACL-Policy line 7 extended deny tcp any 192.168.60.0 
            255.255.255.0 eq ldaps (hitcnt=11) 
access-list Transit-ACL-Policy line 8 extended deny tcp any 192.168.60.0 
            255.255.255.0 eq 3269 (hitcnt=14)
access-list Transit-ACL-Policy line 9 extended deny ip any any (hitcnt=65)
firewall# 

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

• 23 LDAP packets on TCP port 389 (ldap) for ACE line 5
• 19 Microsoft Global Catalog packets on TCP port 3268 for ACE line 6
• 11 LDAP over TLS/SSL packets on TCP port 636 (ldaps) for ACE line 7
• 14 Microsoft Global Catalog with LDAP/SSL packets on TCP port 3269 for ACE line 8

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 available in Cisco Security Appliance System Log Message - 106023.

Information about configuring syslog for the Cisco ASA 5500 Series Adaptive Security Appliance or the Cisco PIX 500 Series Security Appliance is available in Configuring Logging on the Cisco Security Appliance. Information about configuring syslog on the FWSM for Cisco Catalyst 6500 Series switches and Cisco 7600 Series routers is available in Configuring Monitoring and Logging on the Cisco FWSM.

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 vulnerabilities described in this document that have a network attack vector. 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 available in Using the Command Line Interface.

MS08-036, Vulnerabilities in Pragmatic General Multicast (PGM) Could Allow Denial of Service (950762):

firewall#show logging | grep 106023
Jun 05 2008 17:13:52: %ASA-4-106023: Deny protocol 113 src outside:192.168.208.63
   dst inside:192.168.60.5 by access-group "Transit-ACL-Policy" 
Jun 05 2008 17:13:52: %ASA-4-106023: Deny protocol 113 src outside:192.168.208.63
   dst inside:192.168.60.6 by access-group "Transit-ACL-Policy" 
Jun 05 2008 17:14:54: %ASA-4-106023: Deny protocol 113 src outside:192.168.208.63 
   dst inside:192.168.60.7 by access-group "Transit-ACL-Policy" 
firewall#

In the preceding example, the messages logged for the tACL Transit-ACL-Policy show potentially spoofed PGM (IP Protocol 113) packets sent to the address block assigned to affected devices.

MS08-035,Vulnerability in Active Directory Could Allow Denial of Service (953235)

firewall#show logging | grep 106023
Jun 01 2008 15:09:06: %ASA-4-106023: Deny tcp src outside:192.168.50.1/1024 
    dst inside:192.168.60.1/389 by access-group "Transit-ACL-Policy"
Jun 01 2008 15:09:06: %ASA-4-106023: Deny tcp src outside:192.168.50.1/60104 
    dst inside:192.168.60.1/389 by access-group "Transit-ACL-Policy"
Jun 01 2008 15:09:06: %ASA-4-106023: Deny tcp src outside:192.168.50.1/43796 
    dst inside:192.168.60.11/389 by access-group "Transit-ACL-Policy"
Jun 01 2008 15:09:06: %ASA-4-106023: Deny tcp src outside:192.168.50.1/10338 
    dst inside:192.168.60.1/389 by access-group "Transit-ACL-Policy"
Jun 01 2008 15:09:44: %ASA-4-106023: Deny tcp src outside:192.168.50.1/1024 
    dst inside:192.168.60.89/3268 by access-group "Transit-ACL-Policy"
firewall#

In the preceding example, the messages logged for the tACL Transit-ACL-Policy show LDAP packets for TCP port 389 and Microsoft Global Catalog packets on TCP port 3268 sent to the address block assigned to affected devices.

MS08-032, Cumulative Security Update of ActiveX Kill Bits (950760)

Firewall syslog message 500001 will be generated for packets that have been modified using the filter activex command. Additional information about this syslog message is available in Cisco Security Appliance System Log Message - 500001.

Information about configuring syslog for the Cisco ASA 5500 Series Adaptive Security Appliance or the Cisco PIX 500 Series Security Appliance is available in Configuring Logging on the Cisco Security Appliance. Information about configuring syslog on the FWSM for Cisco Catalyst 6500 Series switches and Cisco 7600 Series routers is available in Configuring Monitoring and Logging on the Cisco FWSM.

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 modified packets that could indicate potential attempts to exploit this vulnerability. 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 available in Using the Command Line Interface.

firewall# show logging | grep 500001
Jun 05 2008 10:00:24: %ASA-5-500001: ActiveX content modified
   src 192.168.150.60 dest 192.168.60.63 on interface outside  

Additional information about syslog messages for ASA and PIX security appliances is available in Cisco Security Appliance System Log Messages. Additional information about syslog messages for the FWSM is available in Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Logging Configuration and System Log Messages.

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

Identification: Spoofing Protection Using Unicast Reverse Path Forwarding

Firewall syslog message 106021 will be generated for packets denied by Unicast RPF. Additional information about this syslog message is available in Cisco Security Appliance System Log Message - 106021.

Information about configuring syslog for the Cisco ASA 5500 Series Adaptive Security Appliance or the Cisco PIX 500 Series Security Appliance is available in Configuring Logging on the Cisco Security Appliance. Information about configuring syslog on the FWSM for Cisco Catalyst 6500 Series switches and Cisco 7600 Series routers is available in Configuring Monitoring and Logging on the Cisco FWSM.

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 vulnerabilities described in this document that have a network attack vector. 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 available in Using the Command Line Interface.

firewall#show logging | grep 106021
Jun 5 2008 00:15:13: %ASA-1-106021: Deny UDP reverse path check from
   192.168.60.1 to 192.168.60.100 on interface outside
Jun 5 2008 00:15:13: %ASA-1-106021: Deny UDP reverse path check from
   192.168.60.1 to 192.168.60.100 on interface outside
Jun 5 2008 00:15:13: %ASA-1-106021: Deny TCP reverse path check from
   192.168.60.1 to 192.168.60.100 on interface outside
firewall#

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

    firewall#show asp drop frame rpf-violated 
      Reverse-path verify failed                                 37  

In the preceding example, Unicast RPF has dropped 37 IP packets received on interfaces with Unicast RPF configured.

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

Cisco Intrusion Prevention System

Mitigation: Cisco IPS Signature Event Actions

Cisco Intrusion Prevention System (IPS) appliances and services modules can provide threat detection and help prevent attempts to exploit several of the vulnerabilities described in this document. The following table provides an overview of CVE identifiers and the respective Cisco IPS signatures that will trigger events on potential attempts to exploit these vulnerabilities.

* Fidelity is also referred to as Signature Fidelity Rating (SFR) and is the relative measure of the accuracy of the signature (predefined). The value ranges from 0 through 100 and is set by Cisco Systems, Inc.

Administrators can configure Cisco IPS sensors to perform an event action when an attack is detected. The configured event action performs preventive or deterrent controls to help protect against an attack that is attempting to exploit the vulnerabilities listed in the preceding table.

Exploits that are easily spoofed may cause a configured event action to inadvertently deny traffic from trusted sources.

Cisco IPS sensors are most effective when deployed in inline protection mode combined with the use of an event action. Automatic Threat Prevention for Cisco IPS 6.x sensors deployed in inline protection mode provides threat prevention against an attack that is attempting to exploit the vulnerabilities listed in the preceding IPS table. Threat prevention is achieved through a default override that performs an event action for triggered signatures with a riskRatingValue greater than 90.

Cisco IPS 5.x sensors that are deployed in inline protection mode require an event action configured on a per-signature basis. Alternatively, administrators can configure an override that can perform an event action for any signatures that are triggered and are calculated as a high-risk threat. Using an event action on sensors deployed in inline protection mode provides the most effective exploit prevention.

For additional information about the risk rating and threat rating calculation, reference Risk Rating and Threat Rating: Simplify IPS Policy Management.

IPS Signature Event Data

The following data has been compiled through remote monitoring services provided by the Cisco Remote Management Services team from a sample group of Cisco IPS sensors running Cisco IPS Signature Update version S338 or greater. The purpose of this data is to provide visibility into attempts to exploit the vulnerabilities released as part of the Microsoft June Security Update released on June 10, 2008. This data was gathered from events triggered on July 10, 2008.

Cisco Security Monitoring, Analysis, and Response System

Identification: Cisco Security Monitoring, Analysis, and Response System Incidents

The Cisco Security Monitoring, Analysis, and Response System (Cisco Security MARS) appliance can create incidents on events for the following Microsoft Security Bulletins. After the S338 dynamic signature update has been downloaded, using the following keywords for each of the respective IPS signatures and a query type of All Matching Events on the Cisco Security MARS appliance will provide a report that lists the incidents created by these IPS signatures.

The following screen shot shows the value(s) used to query for events created by IPS signatures related to these vulnerabilities:

The following screen shot shows the query results for these vulnerabilities created by the Cisco Security MARS appliance:

Beginning with the 4.3.1 and 5.3.1 releases of Cisco Security MARS appliances, support for the Cisco IPS dynamic signature updates feature has been added. This feature downloads new signatures from Cisco.com or from a local web server, correctly processes and categorizes received events that match those signatures, and includes them in inspection rules and reports. These updates provide event normalization and event group mapping, and they also enable the MARS appliance to parse new signatures from the IPS devices.

Caution: If dynamic signature updates are not configured, events that match these new signatures appear as unknown event type in queries and reports. MARS will not include these events in inspection rules, thus incidents may not be created for potential threats or attacks that occur within the network.

By default, this feature is enabled but requires configuration. If it is not configured, the following Cisco Security MARS rule will be triggered:

System Rule: CS-MARS IPS Signature Update Failure

When this feature is enabled and configured, administrators can determine the current signature version downloaded by MARS by selecting Help > About and reviewing the IPS Signature Version value.

Additional information about and instructions for configuring dynamic signature updates are available for the Cisco Security MARS 4.3.1 and 5.3.1 releases.

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/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.

Related Information

• Microsoft Security Bulletin Summary for June 2008
• Cisco Applied Mitigation Bulletins
• Understanding Cross-Site Scripting (XSS) Threat Vectors
• Protecting Your Core: Infrastructure Protection Access Control Lists
• Transit Access Control Lists: Filtering at Your Edge
• Cisco IOS NetFlow - Home Page on Cisco.com
• Cisco IOS NetFlow White Papers
• Understanding Access Control List Logging
• Understanding Unicast Reverse Path Forwarding
• Embedded Event Manager in a Security Context
• Identifying Incidents Using Firewall and IOS Router Syslog Events
• A Security-Oriented Approach to IP Addressing
• Cisco Firewall Products - Home Page on Cisco.com
• Understanding Unicast Reverse Path Forwarding
• Unicast Reverse Path Forwarding Loose Mode
• Unicast Reverse Path Forwarding Enhancements for the Internet Service Provider
• Cisco 6.x Intrusion Prevention System
• Cisco IPS 6.x Signature Downloads
• Cisco IPS Signature Search Page
• Risk Rating and Threat Rating: Simplify IPS Policy Management
• Cisco Security Monitoring, Analysis, and Response System
• Cisco Security Agent
• Integrating Cisco Security Agent with Cisco Intrusion Prevention System
• Common Vulnerabilities and Exposures (CVE)

Version 3, June 13, 2008, 5:32 PM: IPS signature event data from Cisco Remote Management Services is available for IPS signatures from June 12, 2008. Information about using the Cisco Security Monitoring, Analysis, and Response System to identify events related to the Microsoft Security Bulletin is also available.

Version 2, June 10, 2008, 5:00 PM: This version was caused by a tool issue and did not contain new information.

Version 1, June 10, 2008, 4:59 PM: This is the initial version of the Cisco Applied Mitigation Bulletin to address the Microsoft Security Bulletin for June 2008.