S E C U R E C O M P U T I N G Intrusion Tolerant Server Infrastructure Dick O’Brien, Tammy Kappel, Clint Bitzer OASIS PI Meeting March 14, 2002

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, Outline OverviewOverview New TechnologiesNew Technologies –Load Distribution –PEN Alerts –Automated Response

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, ITSI Objective Develop an Intrusion Tolerant Server Infrastructure that uses independent network layer enforcement mechanisms to:Develop an Intrusion Tolerant Server Infrastructure that uses independent network layer enforcement mechanisms to: –Reduce intrusions –Prevent propagation of intrusions that do occur –Provide automated load shifting when intrusions are detected –Support automated server recovery Provide uninterrupted service even in the face of malicious attacks that may be successful against one of the systems

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, ITSI Functionality ITSI is a combination of existing and new technologies ExistingExisting –Autonomic Distributed Firewall (3Com Embedded Firewall) Provides network access controlProvides network access control –Heterogeneous web servers –Hardened platforms Linux platform based on Immunix 7.0 and SELinux LSMLinux platform based on Immunix 7.0 and SELinux LSM Windows 2000 uses Kernel Loadable WrappersWindows 2000 uses Kernel Loadable Wrappers –Intrusion Detection Systems NewNew –Load distribution –ADF PEN alerts –Automated response

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, ITSI Prototype SELinux Web ServerWin2k Web Server Windows 2000 IIS Web Server & PHP Response/ Recovery Agent Detection/ Initiating Agent Intrusion Detection Embedded Firewall NIC 2 Embedded Firewall NIC 1 SE Linux Apache & PHP Response/ Recovery Agent Detection/ Initiating Agent Intrusion Detection Embedded Firewall NIC 2 Embedded Firewall NIC 1 AIC Windows 2000 ADF Policy Server Alert Handler Cluster Manager ID Management Embedded Firewall NIC Response/Recovery Controller Application DB Clients

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, PEN Policy External PEN policy Incoming – only allow traffic to web server Outgoing – only allow responses No sniffing, No spoofing Audit any violations Internal PEN policy Incoming – only allow traffic from DB and AIC Outgoing – only allow traffic to DB and AIC No sniffing, No spoofing Audit any violations DB AIC

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, Summary Intrusion tolerance through – –Hardened, heterogeneous platforms – –Automatic response capabilities – –Load sharing between the servers – –Extensive auditing and alert capabilities No need for additional firewalls Scalability through the ability to easily add additional platforms Maintainability through the ability to easily remove and service a platform

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, Load Distribution SELinux Web ServerWin2k Web Server Windows 2000 IIS Web Server & PHP Response/ Recovery Agent Detection/ Initiating Agent Intrusion Detection Embedded Firewall NIC 2 Embedded Firewall NIC 1 SE Linux Apache & PHP Response/ Recovery Agent Detection/ Initiating Agent Intrusion Detection Embedded Firewall NIC 2 Embedded Firewall NIC 1 AIC Windows 2000 ADF Policy Server Alert Handler Cluster Manager ID Management Embedded Firewall NIC Response/Recovery Controller Application DB Clients

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, Load Distribution PEN Agent PEN 2 PEN 1 Load Sharing Rules PEN Agent PEN 2 PEN 1 Load Sharing Rules New Rules from AIC Apache Web Server IIS We b Server

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, Approach Clusters are created with multiple servers sharing a virtual IP addressClusters are created with multiple servers sharing a virtual IP address The shared virtual IP is mapped to a shared MACThe shared virtual IP is mapped to a shared MAC Each server receives all traffic addressed to the shared MACEach server receives all traffic addressed to the shared MAC Rules on the PEN determine what traffic to process and what to throw away based on source IPRules on the PEN determine what traffic to process and what to throw away based on source IP Traffic load can be shifted by modifying PEN rulesTraffic load can be shifted by modifying PEN rules

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, Configuration

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, Lessons Learned Load distribution can be done using special PEN rules with no modification of the PEN firmwareLoad distribution can be done using special PEN rules with no modification of the PEN firmware Shared MAC approach works for servers on a shared network segmentShared MAC approach works for servers on a shared network segment More general approach is feasibleMore general approach is feasible –Develop a centralized approach to changing the MAC used by an EFW NIC from the AIC –Use a multicast address –Do load distribution based on source ports as well as source IP –Add load balancing –Have NICs negotiate load distribution by themselves

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, PEN Alerts SELinux Web ServerWin2k Web Server Windows 2000 IIS Web Server & PHP Response/ Recovery Agent Detection/ Initiating Agent Intrusion Detection Embedded Firewall NIC 2 Embedded Firewall NIC 1 SE Linux Apache & PHP Response/ Recovery Agent Detection/ Initiating Agent Intrusion Detection Embedded Firewall NIC 2 Embedded Firewall NIC 1 AIC Windows 2000 ADF Policy Server Alert Handler Cluster Manager ID Management Embedded Firewall – NIC Response/Recovery Controller Application DB Clients

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, PEN Alerts Alerts are based on audit from the PENAlerts are based on audit from the PEN Alerts are raised onAlerts are raised on –Spoofing violations –Sniffing violations –Matching on any filter rule that has alerting enabled Such as, no initiation of TCP connectionsSuch as, no initiation of TCP connections Alert actions supportedAlert actions supported –Notify Response Server –NT event log –SNMP trap –

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, Approach Store Audit Insert Alert? 1Audit DB Initiate Alert Alert Handler Threshold Exceeded? Alert Configurations Read Alert Actions Audit DB Audit Event

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, Configuration

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, Lessons Learned By basing the alert functionality on the PEN audit, no changes were necessary to the PEN firmwareBy basing the alert functionality on the PEN audit, no changes were necessary to the PEN firmware PEN alerts could be used as sensors for other intrusion detection/response systemsPEN alerts could be used as sensors for other intrusion detection/response systems –PEN alerts, such as No Spoofing, No Sniffing, or No TCP initiation, will not generate false positives –Interface is through the AIC which collects all audit and generates alerts

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, ITSI Prototype SELinux Web ServerWin2k Web Server Windows 2000 IIS Web Server & PHP Response/ Recovery Agent Detection/ Initiating Agent Intrusion Detection Embedded Firewall NIC 2 Embedded Firewall NIC 1 SE Linux Apache & PHP Response/ Recovery Agent Detection/ Initiating Agent Intrusion Detection Embedded Firewall NIC 2 Embedded Firewall NIC 1 AIC Windows 2000 ADF Policy Server Alert Handler Cluster Manager ID Management Embedded Firewall – NIC Response/Recovery Controller Application DB Clients

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, PEN Responses ShiftingShifting –Traffic can be shifted to another server if one goes down BlockingBlocking –Traffic from specified IP addresses can be blocked AuditingAuditing –Traffic from a specified IP address can be audited FishbowlingFishbowling –Traffic from a specified IP address can be routed to a particular server

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, Host Response Agents Detection/Initiating AgentDetection/Initiating Agent – Interfaces with local ID systems to detect intrusions – Initiates Local Responses – Sends Intrusion Event Data to AIC Response/Recovery AgentResponse/Recovery Agent – Performs Local Responses per AIC Check critical files (using Veracity or Tripwire)Check critical files (using Veracity or Tripwire) Disable userDisable user Kill processKill process ShutdownShutdown –Local recovery Restore files, restore registryRestore files, restore registry

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, Response Server Receives Events from Agents Receives Events from Agents Correlates Events Based on Priority Correlates Events Based on Priority Enables User Customizable Responses Based on Event Types Enables User Customizable Responses Based on Event Types Initiates Responses Initiates Responses Manages Web Server Load Sharing Manages Web Server Load Sharing Manages ID Software Manages ID Software Controls Embedded Firewalls Controls Embedded Firewalls

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, Response Configuration

S E C U R E C O M P U T I N G OASIS PI Meeting March 14, Response Components Response Agent Responder Response Agent Initiator Event Handler Event Correlator ResponseInitiator Send Events: Log Event Log Event Restart Restart Store Events Reinitiate Load Share Thru Policy Server Read Config Files: Response Configuration Response Configuration Server Config Server Config Service Data Service Data List of Responses Send Responses Read New Events Local Response File DisableSource Execute Custom Responses Check & Restore Shutdown