Скачать презентацию Defense-in-Depth using Network Virtualization and Network Admission Control Скачать презентацию Defense-in-Depth using Network Virtualization and Network Admission Control

acc74f497048a75601a28c3b563c7979.ppt

  • Количество слайдов: 24

Defense-in-Depth using Network Virtualization and Network Admission Control Steven Carter – stevenca@cisco. com Susan Defense-in-Depth using Network Virtualization and Network Admission Control Steven Carter – [email protected] com Susan Stewart – [email protected] com Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential 1

Agenda § Background/Overview § Network Virtualization Techniques § Network Access Control § Securing the Agenda § Background/Overview § Network Virtualization Techniques § Network Access Control § Securing the Wild, West § Q&A Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential 2

Background § The term “Defense-in-Depth” refers to leveraging the defensive capability of every device Background § The term “Defense-in-Depth” refers to leveraging the defensive capability of every device in the network from the border of the network through the core, distribution, and access portions of the network and into the host itself. § This can be done by combining the following capabilities: – Firewall/IDS at the border to ward of threats before they enter the network – Network virtualization to segregate the physical network into multiple virtual networks to support multiple security levels and services – Network Access Control to authenticate user/hosts onto the network, check their security posture, and place them into the network that matches their requirements Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential 3

Agenda § Background/Overview § Network Virtualization Techniques § Network Access Control § Securing the Agenda § Background/Overview § Network Virtualization Techniques § Network Access Control § Securing the Wild, West § Q&A Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential 4

Network Virtualization § Provide several networks to support varying security postures, applications, etc. § Network Virtualization § Provide several networks to support varying security postures, applications, etc. § One physical network supports many virtual networks § End-user perspective is that of being connected to a dedicated network (independent security policies, routing decisions, etc. ) Visitor Virtual Network Internal Virtual Network Voice Virtual Network Actual Physical Infrastructure Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential 5

Network Device Virtualization § Switch Virtualization: – Data Plane – 802. 1 q VLANs Network Device Virtualization § Switch Virtualization: – Data Plane – 802. 1 q VLANs – Control Plane – Per VLAN Spanning Tree Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential 6

Network Device Virtualization (Cont. ) § Router Virtualization: – Data Plane - Virtual Routing/Forwarding Network Device Virtualization (Cont. ) § Router Virtualization: – Data Plane - Virtual Routing/Forwarding (VRFs) – Control Plane – Multiple instances of routing protocols (OSPF, EIGRP, etc) per routed plane. 802. 1 q, GRE, LSP, Physical Int, Others 802. 1 q or Others VRF Global Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential 7

Data Path Virtualization § Tags: Single Hop Data Path Virtualization 802. 1 q Tags Data Path Virtualization § Tags: Single Hop Data Path Virtualization 802. 1 q Tags Multi-Hop Data Path Virtualization © 2007 Cisco Systems, Inc. All rights reserved. Tags § Tunnels (connection oriented) GRE/m. GRE Label Switched Paths—LSP (MPLS) IP Presentation_ID 802. 1 q Cisco Confidential 8

Putting it Together Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential Putting it Together Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential 9

Agenda § Background/Overview § Network Virtualization Techniques § Network Access Control § Securing the Agenda § Background/Overview § Network Virtualization Techniques § Network Access Control § Securing the Wild, West § Q&A Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential 10

Network Access Control (NAC) § NAC can mean different things to different people, but Network Access Control (NAC) § NAC can mean different things to different people, but for the purposes of this presentation, it should provide three important functions: – User/Host Authentication – The network should be able to authenticate the user (or at least the host) onto the network. – Host Posture Verification – The ability to make sure that the host posture (virus definitions, patches, firewalls, etc. ) match the policy of the network for which it is destined. – Host Remediation – The placement of the host into the correct network § NAC provides that connection between Network Security and Host Security Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential 11

Network Access Control (NAC) (Cont. ) First, establish ACCESS POLICIES. Then: Authenticate & Authorize Network Access Control (NAC) (Cont. ) First, establish ACCESS POLICIES. Then: Authenticate & Authorize Quarantine & Enforce § Enforces authorization policies and privileges § Isolate non-compliant devices from rest of network § Supports multiple user roles § MAC and IP-based quarantine effective at a per-user level Scan & Evaluate § Agent scan for required versions of hotfixes, AV, etc § Network scan for virus and worm infections and port vulnerabilities Update & Remediate § Network-based tools for vulnerability and threat remediation § Help-desk integration LIMITED COMPLIANCE = LIMITED NETWORK ACCESS Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential 12

What about the exceptions? § Hosts that do not support the mechanisms can be What about the exceptions? § Hosts that do not support the mechanisms can be dealt with in various ways (external scanning, web authentication, etc. ), but in general garner a lower level of trust and can be segregated from the general population § Because of their very nature, Research and Education networks have a number of hosts (upwards of 25%) that do not fit a supported configuration § There must be a credible option for these hosts, otherwise, you diminish much of the effect of implementing NAC in the first place Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential 13

Addressing the Outliers § One option is to put a firewall in front of Addressing the Outliers § One option is to put a firewall in front of each and every host that cannot comply. This can be done with physical firewalls (i. e. a small firewall in front of every host): – Pros - Straight-forward and easy for the policy people to understand buy into; Depending on the situation, could be more cost-effective – Cons – Logistically difficult and hard to administer; not scalable to large number Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential 14

Addressing the Outliers (Cont. ) § You can also do it (yes, you guessed Addressing the Outliers (Cont. ) § You can also do it (yes, you guessed it) VIRTUALLY § Difficult to do with a standard 802. 1 q VLANs because it is not scalable and difficult to avoid needing proper subset addresses per VLAN § Difficult to do with ACLs because of the shear number needed. Also not scalable and is difficult to maintain § Solution: Use sufficient security techniques to obviate the need for real firewalls Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential 15

Agenda § Background/Overview § Network Virtualization Techniques § Network Access Control § Securing the Agenda § Background/Overview § Network Virtualization Techniques § Network Access Control § Securing the Wild, West § Q&A Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential 16

Securing the Wild, West § Overview: – Private VLANs to separate broadcast domains – Securing the Wild, West § Overview: – Private VLANs to separate broadcast domains – Port Security prevents MAC spoofing – DHCP snooping prevents client attack on the switch and server – Dynamic ARP Inspection adds security to ARP using DHCP snooping table – IP Source Guard adds security to IP source address using DHCP snooping table Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential 17

Securing the Wild, West (Cont. ) Primary VLAN § Private VLANs – PVLANs allow Securing the Wild, West (Cont. ) Primary VLAN § Private VLANs – PVLANs allow segregating broadcast segment into a nonbroadcast multi-access-like segment. – Traffic that comes to a switch from a promiscuous port is able to go out on all the ports that belong to the same primary VLAN. Secondary VLANs Distribution Access – Traffic that comes to a switch from a port mapped to a secondary VLAN (it can be either an isolated, a community, or a two -way community VLAN) can be forwarded to a promiscuous port or a port belonging to the same community VLAN. Secondary VLAN (isolated) Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential Secondary VLAN (community) 18

Securing the Wild, West (Cont. ) § Port Security – Restrict a port's ingress Securing the Wild, West (Cont. ) § Port Security – Restrict a port's ingress traffic by limiting the MAC addresses that are allowed to send traffic into the port – Number of address on the port is configurable Only 1 MAC Address Allowed on the Port: Shutdown – Dynamically learned MAC address cuts down on administrative overhead – “sticky” and non-”sticky” variants give the option of retaining learned address across port-down events Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential 19

Securing the Wild, West (Cont. ) § DHCP Snooping – Acts like a firewall Securing the Wild, West (Cont. ) § DHCP Snooping – Acts like a firewall between untrusted hosts and trusted DHCP servers – Validates and Rate-Limits DHCP messages received from untrusted sources and filters out invalid messages. – Builds and maintains the DHCP snooping binding database, which contains information about untrusted hosts with leased IP addresses to validate subsequent requests from untrusted hosts DHCP Snooping DHCP Requests Untrusted © 2007 Cisco Systems, Inc. All rights reserved. Trusted DHCP Server Unauthorized DHCP Response Presentation_ID DHCP Responses Cisco Confidential 20

Securing the Wild, West (Cont. ) § Dynamic Arp Inspection – Intercepts, logs, and Securing the Wild, West (Cont. ) § Dynamic Arp Inspection – Intercepts, logs, and discards ARP packets with invalid IP-to-MAC address bindings – Valid ARP packets based upon DHCP snooping binding database or from user-configured ARP access control lists (ACLs) – Configurable to drop ARP packets when either the IP address or the MAC address in the body does not match the Ethernet header DHCP Snooping DHCP Requests Untrusted Unauthorized DHCP Response Presentation_ID I’m your GW: 10. 1. 1. 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential DHCP Responses Trusted Not by my binding table DHCP Server 21

Securing the Wild, West (Cont. ) § IP Source Guard – IP source guard Securing the Wild, West (Cont. ) § IP Source Guard – IP source guard prevents IP spoofing by allowing only the IP addresses that are obtained through DHCP snooping on a particular port. –This process restricts the client IP traffic to those source IP addresses that are obtained from the DHCP server; any IP traffic with a source IP address other than that in the PACLs permit list is filtered out DHCP Snooping DHCP Requests Untrusted Unauthorized DHCP Response Presentation_ID I’m your GW: 10. 1. 1. 1 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential DHCP Responses Trusted Not by my Port ACL DHCP Server 22

The End Questions? Comments? Criticisms? For more information: Steven Carter – stevenca@cisco. com Susan The End Questions? Comments? Criticisms? For more information: Steven Carter – [email protected] com Susan Stewart – [email protected] com Presentation_ID © 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential 23