Intrusion Tolerant Distributed Object Systems Joint IA&S PI Meeting Honolulu, HI July 17-21, 2000 Gregg Tally

July 17-21, Motivation Mission critical applications being developed using CORBA on COTS platforms CORBA Security protects at middleware level, but applications vulnerable to O/S and network attacks Fault Tolerant CORBA does not protect against malicious faults

July 17-21, Technical Objectives Provide intrusion tolerance for CORBA applications System level approach – Middleware Eliminate reliance on any single server – secure, reliable group communication directly between clients and replicated servers Detect Byzantine (arbitrary) faults in servers Support heterogeneity (diversity of implementation) – Boundary controllers (firewalls) Protocol inspection End-to-end authentication between clients and servers

July 17-21, Existing Approaches OMG supports Fault Tolerance for CORBA – Not intrusion tolerant – Not fully interoperable – No firewall support Prior and Current Research – Avoided ORB changes by intercepting process level communications; forces homogeneous server implementation – Use of “primary” or “lead” server; cannot tolerate Byzantine faults – Ensemble, Maestro, AQuA, Rampart, Eternal, others

July 17-21, Technical Approach Leverage prior work on fault tolerant CORBA; secure, reliable, authenticated multicast; total ordering; Byzantine fault detection Active replication of servers with voting Protect client and server hosts with application proxy firewall; include firewall in multicast group Integrate with open-source ORB – Detect value faults above CDR encode/decode layer – Replace transport layer with secure, reliable, authenticated multicast – Handle duplicate requests and replies

July 17-21, Conceptual Overview Firewall Secure, Reliable, Auth. Multicast GIOP Proxy Client Application Code IT ORB Value Fault Detection / Voting Redundant Msg. Exclusion Encode/Decode Time, Crash, other Fault Detection Secure, Reliable, Auth. Multicast Firewall M-Cast GIOP Proxy Server Application Code IT ORB Server Application Code IT ORB Server Application Code IT ORB Firewall M-Cast GIOP Proxy Firewall M-Cast GIOP Proxy Client-Side Firewall Server-Side Firewalls Redundant Servers

July 17-21, Approach -- What’s Different ? All servers are equal – eliminate need for “primary” or “lead” server Detect value faults in the ORB – encoding of CORBA messages depends on the source platform (i.e, byte ordering) – permits heterogeneous implementations Application proxy firewall integrated into the architecture – better protection for COTS client and server hosts – end-to-end authentication of client and server – may have better performance than IIOP/SSL proxies

July 17-21, Risks and Mitigation Plans Performance of secure, reliable, authenticated multicast – Mitigation Plan: Evaluate and experiment with existing research prototypes Design replaceable transport layer Take advantage of research advances as they become available Defense against DoS attacks by compromised servers – Mitigation Plan: Rely on intruder tracing (IDIP?) to find source and block

July 17-21, Expected Achievements At least one implementation of an ORB on two more more heterogeneous platforms that tolerates Byzantine faults Integrated application proxy firewall support to protect COTS client and server hosts Understand trade-off between performance and degrees of intrusion tolerance

July 17-21, Metrics Cost/benefit of redundant servers – Tolerance of Byzantine faults (number of faulted servers) vs. impact on throughput due to additional replication – Throughput measured by operations per second Countermeasure Characterization using either IA or IASET methodology Experimentation at the TIC to validate countermeasure claims

July 17-21, Policy Issues Assumptions – Other mechanisms enforce QoS and QoP policies – CORBA Security could be added to architecture to provide other services (access control, audit, non-repudiation, etc.) – Can integrate with intruder tracing mechanisms (e.g., IDIP) to handle denial of service attacks Enforcement Mechanisms – Need policy for group membership: servers, clients, and firewalls – Standard firewall permit/deny policy extended for secure, reliable, authenticated multicast

July 17-21, Schedule

July 17-21, Technology Transfer Work with OMG to revise existing specifications, create new specifications – Fault Tolerance specification – Unreliable Multicast specification – Firewall specification Joint experimentation with other DARPA and DoD programs Conferences and workshops