Security Intelligence Operations

IPS signature event data from Cisco Remote Management Services is available for IPS signatures from October 8, 2009.

Contents

Introduction

Microsoft announced five security bulletins that contain eight vulnerabilities as part of the monthly security bulletin release on September 8, 2009. A summary of these bulletins is on the Microsoft website at http://www.microsoft.com/technet/security/bulletin/ms09-sep.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:

• MS09-045
• MS09-047
• MS09-049

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.

• MS09-046
• MS09-048

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

MS09-046, Vulnerability in DHTML Editing Component ActiveX Control Could Allow Remote Code Execution (956844): This vulnerability has been assigned CVE identifier CVE-2009-2519. This vulnerability can be exploited remotely without authentication and requires user interaction. Successful exploitation of this vulnerability may allow arbitrary code execution, which enables an attacker to learn information about the affected device. The attack vector for exploitation of CVE-2009-2519 is through HTTP packets, which typically use TCP port 80 but may also use TCP ports 3128, 8000, 8010, 8080, 8888, and 24326. This vulnerability can be exploited through client software, web-based threats (including ActiveX attacks, cross-site scripting, phishing, and web-based e-mail), e-mail attachments, and files stored on network shares.

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. Furthermore, information about ActiveX exploits and mitigations using Cisco firewall technologies is presented in the Cisco Whitepaper Preventing ActiveX Exploits with Cisco Firewall Application Layer Protocol Inspection.

MS09-048, Vulnerabilities in Windows TCP/IP Could Allow Remote Code Execution (967723): These vulnerabilities have been assigned CVE identifiers CVE-2008-4609, CVE-2009-1925, and CVE-2009-1926. These vulnerabilities can be exploited remotely without authentication and without user interaction.

Successful exploitation of the vulnerability for CVE-2008-4609 may cause the affected device to crash or reload resulting in a denial of service (DoS) condition. Repeated attempts to exploit this vulnerability could result in a sustained DoS condition. The attack vector for exploitation of CVE-2008-4609 is through TCP packets.

Successful exploitation of the vulnerability for CVE-2009-1925 may allow arbitrary code execution, cause the affected device to crash or reload resulting in a DoS condition, or allow information disclosure, which enables an attacker to learn information about the affected device. Repeated attempts to exploit this vulnerability could result in a sustained DoS condition. The attack vector for exploitation of CVE-2009-1925 is through TCP packets.

Successful exploitation of the vulnerability for CVE-2009-1926 may cause the affected device to stop responding, resulting in a DoS condition. Repeated attempts to exploit this vulnerability could result in a sustained DoS condition. The attack vector for exploitation of CVE-2009-1926 is through TCP packets.

For additional information about mitigating the vulnerabilities for CVE-2008-4609 and CVE-2009-1926 refer to the Cisco Applied Mitigation Bulletin, Cisco Applied Mitigation Bulletin: Identifying and Mitigating Exploitation of the TCP State Manipulation Denial of Service Vulnerabilities in Multiple Cisco Products and the corresponding Cisco Security Advisory: TCP State Manipulation Denial of Service Vulnerabilities in Multiple Cisco Products.

Information about vulnerable, unaffected, and fixed software is available in the Microsoft Security Bulletin Summary for September 2009, which is available at the following link: http://www.microsoft.com/technet/security/bulletin/ms09-sep.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:

• MS09-045
• MS09-047
• MS09-049

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.

• MS09-046
• MS09-048

Effective exploit prevention can also be provided by the Cisco ASA 5500 Series Adaptive Security Appliance, the Cisco PIX 500 Series Security Appliance, and the Firewall Services Module (FWSM) for Cisco Catalyst 6500 Series switches and Cisco 7600 Series routers using Application layer protocol inspection and the built in TCP Normalizer function.

These protection mechanisms filter and drop packets that are attempting to exploit the vulnerabilities that have a network attack vector.

Effective exploit prevention can also be provided by the Cisco ACE Application Control Engine Appliance and Module using Application Protocol Inspection.

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 records can provide visibility into network-based exploitation attempts.

Cisco IOS Software, Cisco ASA and Cisco PIX security appliances, FWSM firewalls, and Cisco ACE Application Control Engine Appliance and Module can provide visibility through syslog messages and 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 NetFlow
• Cisco ASA, PIX, and FWSM Firewalls
• Cisco ACE
• Cisco Intrusion Prevention System
• Cisco Security Monitoring, Analysis, and Response System

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 in MS09-046 and MS09-048 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  06 0984 00A1     1
Gi0/0         192.168.11.54   Gi0/1         192.168.60.158  06 0911 01BD     3
Gi0/1         192.168.150.60  Gi0/0         10.89.16.226    11 0016 12CA     1
Gi0/0         192.168.13.97   Gi0/1         192.168.60.28   06 0B3E 00A1     5
Gi0/0         192.168.10.17   Gi0/1         192.168.60.97   06 0B89 0017     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  06 0BD7 13C4     7
Gi0/0         10.89.16.226    Gi0/1         192.168.150.60  06 12CA 0016     1

In the preceding example, there are multiple flows for TCP traffic.

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 TCP traffic sent and also investigate the flows to determine whether they are sourced from untrusted hosts or networks.

router#show ip cache flow | include SrcIf|_06_

SrcIf         SrcIPaddress    DstIf         DstIPaddress    Pr SrcP DstP  Pkts
Gi0/0         192.168.10.201  Gi0/1         192.168.60.102  06 0984 00A1     1
Gi0/0         192.168.11.54   Gi0/1         192.168.60.158  06 0911 01BD     3
Gi0/0         192.168.13.97   Gi0/1         192.168.60.28   06 0B3E 00A1     5
Gi0/0         192.168.10.17   Gi0/1         192.168.60.97   06 0B89 0017     1
Gi0/0         192.168.12.185  Gi0/1         192.168.60.239  06 0BD7 13C4     7

Cisco ASA, PIX, and FWSM Firewalls

Mitigation: TCP Normalization

The TCP normalization feature identifies abnormal packets that the security appliance can act on when they are detected; for example, the security appliance can allow, drop, or clear the packets. The TCP normalizer includes non-configurable actions and configurable actions. Typically, non-configurable actions that drop or clear connections apply to packets that are considered malicious. TCP Normalization is available beginning in software release 7.0(1) for the Cisco ASA 5500 Series Adaptive Security Appliance and the Cisco PIX 500 Series Security Appliance and in software release 3.1(1) for the Firewall Services Module.

TCP normalization is enabled by default and drops packets that may exploit CVE-2009-1925. Protection against packets that may exploit CVE-2009-1925 is a non-configurable TCP normalization action; no configuration changes are required to enable this functionality.

Additional information about TCP Normalization is in the Configuring TCP Normalization section of the Cisco Security Appliance Command Line Configuration Guide.

Mitigation: Application Layer Protocol Inspection

Application layer protocol inspection is available beginning in software release 7.2(1) for the Cisco ASA 5500 Series Adaptive Security Appliance and the Cisco PIX 500 Series Security Appliance and in software release 4.0(1) for the Firewall Services Module. This advanced security feature performs deep packet inspection of traffic that transits 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.

Additional information about application layer protocol inspection is in the Applying Application Layer Protocol Inspection section of the Cisco Security Appliance Command Line Configuration Guide.

Caution: Application layer protocol inspection will decrease firewall performance. Administrators are advised to test performance impact in a lab environment before this feature is deployed in production environments.

HTTP Application Inspection
By using the HTTP inspection engine on the Cisco ASA 5500 Series Adaptive Security Appliances, the Cisco PIX 500 Series Security Appliances, and the Firewall Services Module, administrators can configure regular expressions (regexes) for pattern matching and construct inspect class maps and inspect policy maps. These methods can help protect against specific vulnerabilities, such as CVE-2009-2519, and other threats that may be associated with HTTP traffic. The following HTTP application inspection configuration uses the Cisco 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 ports for the Cisco IPS #WEBPORTS variable. The HTTP application inspection policy will drop connections where the HTTP response body contains any of the regexes that are configured to match the ActiveX control that is associated with this vulnerability.

Caution: The configured regexes can match text strings at any location 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 affected. Additional information about regex syntax is in Creating a Regular Expression.

For additional information, reference the Preventing ActiveX Exploits with Cisco Firewall Application Layer Protocol Inspection Applied Intelligence white paper.

 !
 !-- Configure regexes for the ActiveX Class ID 
 !-- "2D360201-FFF5-11D1-8D03-00A0C959BC0A" and Program ID
 !-- "DHTMLEdit1.LoadURL" that are associated
 !- with this vulnerability
 ! 
 regex CLSID_activeX "2[Dd]360201[-][Ff][Ff][Ff]5[-]11[Dd]1[-]8[Dd]03
[-]00[Aa]0[Cc]959[Bb][Cc]0[Aa]"
 regex ProgID_activeX "[Dd][Hh][Tt][Mm][Ll][Ee][Dd][Ii][Tt]1\.[Ll][Oo]
[Aa][Dd][Uu][Rr][Ll]"
 ! 
 !-- Configure a regex class to match on the regular  
 !-- expressions that are configured above
 ! 
 class-map type regex match-any vulnerable-activeX-Class
  match regex CLSID_activeX
  match regex ProgID_activeX
 !
 !-- Configure an object group for the default ports that 
 !-- are used by the Cisco IPS #WEBPORTS variable, which 
 !-- are TCP ports 80 (www), 3128, 8000, 8010, 8080, 8888, 
 !-- and 24326
 !

 object-group service WEBPORTS tcp
  port-object eq www 
  port-object eq 3128 
  port-object eq 8000 
  port-object eq 8010 
  port-object eq 8080 
  port-object eq 8888 
  port-object eq 24326 
 !
 !-- Configure an access list that uses the WEBPORTS object 
 !-- group, which will be used to match TCP packets that 
 !-- are destined to the #WEBPORTS variable that is used 
 !-- by a Cisco IPS device
 !
 access-list Webports-ACL extended permit tcp any any object-group WEBPORTS 
 !
 !-- Configure a class that uses the above-configured
 !-- access list to match TCP packets that are destined
 !-- to the ports that are used by the Cisco IPS #WEBPORTS
 !-- variable
 !
 class-map Webports-Class
  match access-list Webports-ACL
 !
 !-- Configure an HTTP application inspection policy that  
 !-- looks for and drops connections that contain HTTP  
 !-- protocol violations and looks for and drops connections   
 !-- that contain the regexes for the affected ActiveX Class
 !-- ID or Program ID that are configured above
 ! 
 policy-map type inspect http http-Policy
  parameters
 !
 !-- "protocol-violation" below is not required to
 !-- mitigate this vulnerability 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
  match response body regex class vulnerable-activeX-Class
   drop-connection log
 !
 !-- Add the above-configured "Webports-Class" that matches 
 !-- TCP packets that are destined to the default ports  
 !-- that are used by the Cisco IPS #WEBPORTS variable to  
 !-- the default policy  "global_policy" and use it to 
 !-- inspect HTTP traffic that transits the firewall
 ! 

 policy-map global_policy
  class Webports-Class
   inspect http http-Policy  
 !
 !-- By default, the policy "global_policy" is applied 
 !-- globally, which results in the inspection of 
 !-- traffic that enters the firewall from all interfaces 
 !
 service-policy global_policy global

For additional information about the configuration and use of object groups, reference the Cisco Security Appliance Command Reference for object-group.

Additional information about HTTP application inspection and the MPF is in the HTTP Inspection Overview section of the Cisco Security Appliance Command Line Configuration Guide.

Identification: TCP Normalization

For the Cisco ASA 5500 Series Adaptive Security Appliance and the Cisco PIX 500 Series Security Appliance the show asp drop command can identify the number of packets that the TCP normalization feature has dropped, as shown in the following example:

 


firewall# show asp drop frame


tcp-paws-fail 
TCP packet failed PAWS test (tcp-paws-fail) 15 

firewall#
  

In the preceding example, TCP normalization has dropped 15 TCP packets in which the timestamp header option fails the PAWS (Protect Against Wrapped Sequences) test. Absence of TCP packet failed PAWS test (tcp-paws-fail) output indicates that TCP normalization on the firewall has not dropped any TCP packets in which the timestamp header option fails the PAWS test.

Due to architectural differences, the show asp drop output is not available for the Firewall Services Module.

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

Identification: Application Layer Protocol Inspection

Firewall syslog message 415007 will be generated when an HTTP message body matches a user-defined regular expression. The syslog message will identify the corresponding HTTP class and HTTP policy and indicate the action applied to the HTTP connection. Additional information about this syslog message is in Cisco Security Appliance System Log Message - 415007.

Information about configuring syslog for the Cisco ASA 5500 Series Adaptive Security Appliance or the Cisco PIX 500 Series Security Appliance is in Monitoring the Security Appliance - Configuring and Managing Logs. 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 attempts to exploit this vulnerability. Administrators can 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.

HTTP Application Inspection

firewall#show logging | grep 415007
  Aug 31 2009 14:35:54: %ASA-5-415007: HTTP - matched response 
         body regex class vulnerable-activeX-Class in policy-map 
         http-Policy, Body matched - Dropping connection from 
         outside:192.0.2.117/4369 to inside:192.168.60.65/80
  Aug 31 2009 14:36:57: %ASA-5-415007: HTTP - matched response 
         body regex class vulnerable-activeX-Class in policy-map 
         http-Policy, Body matched - Dropping connection from 
         outside:192.0.2.150/4370 to inside:192.168.60.65/80 

With HTTP application inspection enabled, the show service-policy inspect protocol command will identify the number of HTTP packets that are inspected and dropped by this feature. The following example shows output for show service-policy inspect http:

firewall# show service-policy inspect http

Global policy: 
  Service-policy: global_policy
    Class-map: inspection_default
    Class-map: Webports-Class
      Inspect: http http-Policy, packet 5025, drop 20, reset-drop 0
        protocol violations
          packet 0
        match response body regex class vulnerable-activeX-Class
          drop-connection log, packet 20

Cisco ACE

Mitigation: TCP Normalization

TCP normalization is a Layer 4 feature that consists of a series of checks that the Cisco ACE performs at various stages of a flow, beginning with the initial connection setup through the closing of a connection.Many of the segment checks can be controlled or altered by configuring one or more advanced TCP connection settings. The ACE uses these TCP connection settings to decide which checks to perform and whether to discard a TCP segment based on the results of the checks. The ACE discards segments that appear to be abnormal or malformed.

TCP normalization is enabled by default and drops packets that may exploit CVE-2009-1925. Protection against packets that may exploit CVE-2009-1925 is a non-configurable TCP normalization action; no configuration changes are required to enable this functionality.

Additional information about TCP Normalization is in the Configuring TCP/IP Normalization and IP Reassembly Parameters section of the Cisco ACE 4700 Series Appliance Security Configuration Guide.

Mitigation: Application Protocol Inspection

Application layer protocol inspection is available for the Cisco ACE Application Control Engine Appliance and Module. This advanced security feature performs deep packet inspection of traffic that transits the Cisco ACE. Administrators can 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.

Additional information about application protocol inspection is in the Configuring Application Protocol Inspection section of the Application Control Engine Module Security Configuration Guide.

HTTP Deep Packet Inspection

To conduct HTTP deep packet inspection, administrators can configure regular expressions (regexes) for pattern matching and construct inspect class maps and inspect policy maps. These methods can help protect against specific vulnerabilities, such as CVE-2009-2519, and other threats that may be associated with HTTP traffic. The following HTTP application protocol inspection configuration inspects traffic on TCP ports 80, 3128, 8000, 8010, 8080, 8888, and 24326, which are the default ports for the Cisco IPS #WEBPORTS variable. The HTTP application protocol inspection policy will drop connections where the HTTP content contains any of the regexes that are configured to match the ActiveX control that is associated with this vulnerability.

Caution: The configured regexes can match text strings at any location in the content of an HTML packet. Care should be taken to ensure that legitimate business applications that use matching text strings without calling the ActiveX control are not affected.

 !
 !-- Configure an HTTP application inspection class that
 !-- looks HTTP packets that contain the regexes for the
 !-- ActiveX Class ID 
 !-- "2D360201-FFF5-11D1-8D03-00A0C959BC0A" 
 !-- and 
 !-- ActiveX Program ID
 !-- "DHTMLEdit1.LoadURL" 
 !-- that are associated with this vulnerability
 ! 

 class-map type http inspect match-any vulnerable-activeX-http-class
   match content ".*2[Dd]360201[-][Ff][Ff][Ff]5[-]11[Dd]1[-]8[Dd]03[-]
00[Aa]0[Cc]959[Bb][Cc]0[Aa].*"
   match content ".*[Dd][Hh][Tt][Mm][Ll][Ee][Dd][Ii][Tt]1\.[Ll][Oo][Aa]
[Dd][Uu][Rr][Ll].*"
 !
 !-- Configure an HTTP application inspection policy that
 !-- looks for and resets connections that contain
 !-- the regexes for the ActiveX Class ID  or 
 !-- Program ID that are configured above
 !

 policy-map type inspect http all-match vulnerable-activeX-http-policy
   class vulnerable-activeX-http-class
     reset
 !
 !-- Configure an access list that matches TCP packets
 !-- that are destined to the #WEBPORTS variable that is
 !-- used by a Cisco IPS device
 !
 access-list WEBPORTS line 8 extended permit tcp any any eq www 
 access-list WEBPORTS line 16 extended permit tcp any any eq 3128 
 access-list WEBPORTS line 24 extended permit tcp any any eq 8000 
 access-list WEBPORTS line 32 extended permit tcp any any eq 8010 
 access-list WEBPORTS line 40 extended permit tcp any any eq 8080 
 access-list WEBPORTS line 48 extended permit tcp any any eq 8888 
 access-list WEBPORTS line 56 extended permit tcp any any eq 24326 

 !
 !-- Configure a Layer 4 class that uses the above-configured
 !-- access list to match TCP packets that are destined
 !-- to the ports that are used by the Cisco IPS #WEBPORTS
 !-- variable
 !
 class-map match-all L4-http-class
   match access-list WEBPORTS
 !
 !-- Configure a Layer 4 policy that applies the HTTP application
 !-- inspection policy configured above to TCP packets that
 !-- are destined to the ports that are used by the Cisco IPS
 !-- #WEBPORTS variable
 !
 policy-map multi-match L4-http-inspect-policy
   class L4-http-class
     inspect http policy vulnerable-activeX-http-policy
 !
 !-- Apply the configuration to a specific vlan interface,
 !-- which results in the inspection of traffic that enters
 !-- the ACE from this interface only
 !
 !-- The configuration could also be applied globally
 !-- which is not shown here
 !

 interface vlan 200
   service-policy input L4-http-inspect-policy

Identification: TCP Normalization

The Cisco ACE Application Control Engine Appliance and Module does not provide show command output for packets dropped while attempting to exploit CVE-2009-1925.

Identification: Application Protocol Inspection

HTTP Deep Packet Inspection

When HTTP deep packet inspection is enabled, the show service-policy policynamedetail command will identify the number of HTTP connections that are inspected and dropped by this feature. The following example shows output for show service-policy L4-http-inspect-policy detail :

ACE/Admin# show service-policy L4-http-inspect-policy detail


Status     : ACTIVE
-----------------------------------------
Interface: vlan 200 
  service-policy: L4-http-inspect-policy
    class: L4-http-class
      inspect http:
        L7 inspect policy : vulnerable-activeX-http-policy

        Url Logging: DISABLED
        curr conns       : 0         , hit count        : 3
        dropped conns    : 0
        client pkt count : 1953      , client byte count: 383883
        server pkt count : 1839      , server byte count: 750891
        conn-rate-limit      : 0         , drop-count : 0
        bandwidth-rate-limit : 0         , drop-count : 0
        L4 policy stats:
          Total Req/Resp: 542        , Total Allowed: 539
          Total Dropped : 3          , Total Logged : 0  
        L7 Inspect policy : vulnerable-activeX-http-policy
          class/match : vulnerable-activeX-http-class
            Inspect action :
               reset
            Total Inspected      : 542        , Total Matched: 3
            Total Dropped OnError: 0 

In the preceding example, 542 HTTP connections have been inspected and 3 HTTP connections have been dropped.

Additional information about about HTTP Deep Packet Inspection and Application Protocol Inspection is in the Configuring Application Protocol Inspection section of the Application Control Engine Module Security Configuration Guide.

Cisco Intrusion Prevention System

Mitigation: Cisco IPS Signature Event Actions

Administrators can use the Cisco Intrusion Prevention System (IPS) appliances and services modules to 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.

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 that are deployed in inline protection mode provides threat prevention against an attack that is attempting to exploit the vulnerability that is described in this document. 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 S430 or greater. The purpose of this data is to provide visibility into attempts to exploit the vulnerabilities released as part of the Microsoft September Security Update released on September 8, 2009. This data was gathered from events triggered on October 8, 2009.

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 S430 dynamic signature update has been downloaded, using the following keywords for each of the respective IPS signatures and a query type of All Matching Event Raw Messages on the Cisco Security MARS appliance will provide a report that lists the incidents created by these IPS signatures.

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. Because MARS will not include these events in inspection rules, 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 dynamic signature updates 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 September 2009
• Cisco Applied Mitigation Bulletins
• Cisco Security Intelligence Operations
• Understanding Cross-Site Scripting (XSS) Threat Vectors
• Cisco IOS NetFlow - Home Page on Cisco.com
• Cisco IOS NetFlow White Papers
• NetFlow Performance Analysis
• Cisco Firewall Products - Home Page on Cisco.com
• Cisco ACE Application Control Engine Module Documentation
• Cisco 6.x Intrusion Prevention System
• Cisco IPS 6.x Signature Downloads
• Cisco IPS Signature Search Page
• Cisco Security Monitoring, Analysis, and Response System
• Common Vulnerabilities and Exposures (CVE)

Version 4, September 23, 2009, 9:46 AM: IPS signature event data from Cisco Remote Management Services is available for IPS signatures from September 22, 2009.

Version 3, September 16, 2009, 4:44 PM: IPS signature event data from Cisco Remote Management Services is available for IPS signatures from September 15, 2009.

Version 2, September 11, 2009, 4:56 PM: IPS signature event data from Cisco Remote Management Services is available for IPS signatures from September 9, 2009.

Version 1, September 8, 2009, 4:53 PM: This initial version of the Cisco Applied Mitigation Bulletin addresses the Microsoft Security Bulletin Release for September 2009.