Mobile Agents

1. Mobile Agents By Olga Gelbart rosa@seas.gwu.edu

2. What is an agent? • A program (“software agent”), e.g., • Personal assistant (mail filter, scheduling) • Information agent (tactical picture agent) • E-commerce agent (stock trader, bidder) • Recommendation agent (Firefly, Amazon.com) • A program that can • interact with users, applications, and agents • collaborate with the user • Software agents help with repetitive tasks http://agent.cs.dartmouth.edu/

3. Is everything an “agent”? • Not all programs are agents • Agents are • customized • persistent • autonomous • adaptive http://agent.cs.dartmouth.edu/

4. What is a mobile agent? Search engine Machine A Machine B • Mobile agent: Agent that • migrates from machine to machine • in a heterogeneous network • at times of its own choosing http://agent.cs.dartmouth.edu/

5. Definition In a broad sense, an agent is any program that acts on behalf of a (human) user. A mobile agent then is a program which represents a user in a computer network, and is capable of migrating autonomously from node to node, to performs some computation on behalf of the user.

6. Agent Host C Host A Agent Network Agent Host B How it works?

7. Mobile Agent Attributes • Code • State • Execution state • Object state • Name • Identifier • Authority • Agent system type • Location

8. Evolution of the “mobile agent” paradigm

9. Assumptions about computer systems violated by mobile agents • Whenever a program attempts some action, we can easily identify a person to whom that action can be attributed, and it is safe to assume that that person intends the action to be taken. • Only persons that are know to the system can execute programs on the system. • There is one security domain corresponding to each user; all actions within that domain can be treated the same way. • Single-user systems require no security. • Essentially all programs are obtained from easily identifiable and generally trusted sources • The users of a given piece of software are restrained by law and custom from various actions against the manufacturer’s interests

10. Assumptions violated by mobile agents (cont’d) • Significant security threats come from attackers running programs with the intent of accomplishing unauthorized results. • Programs cross administrative boundaries only rarely, and only when people intentionally transmit them. • A given instance of a program runs entirely on one machine; processes do not cross administrative boundaries at all. • A given program runs on only one particular operating system. • Computer security is provided by the operating system

11. Benefits of mobile agents • Bandwidth conservation • Reduction of latency • Reduction of completion time • Asynchronous (disconnected) communications • Load balancing • Dynamic deployment

12. Dataset Reason 1: Bandwidth conservation Text documents, numerical data, etc. Client/Proxy Server Dataset Client/Proxy Server http://agent.cs.dartmouth.edu/

13. Reason 2: Reduce latency Sumatra chat server (a “reflector”) 1. Observe high average latency to clients 2. Move to better location http://agent.cs.dartmouth.edu/

14. Reason 3: Reduce Completion Time Efficiency 1. Send code with unique query Low bandwidth channel Mobile users 3. Return requested data 2. Perform multi-step queries on large, remote, heterogeneous databases http://agent.cs.dartmouth.edu/

15. Reason 4: Disconnected communication and operation X X Before X X After http://agent.cs.dartmouth.edu/

16. Reason 5: Load balancing Jobs/Load Jobs/Load migrate in a heterogeneous network of machines http://agent.cs.dartmouth.edu/

17. Map, terrain databases Command post Unique needs: maps, weather, tactical updates.... Weather Tactical updates Reason 6: Dynamic Deployment http://agent.cs.dartmouth.edu/

18. Threats posed by mobile agents • Destruction of • data, hardware, current environment • Denial of service • block execution • take up memory • prevention of access to resources/network • Breach of privacy / theft of resources • obtain/transmit privileged information • use of covert channels • Harassment • Display of annoying/offensive information • screen flicker • Repudiation • ability to deny an event / action ever happened

19. Protection methods against malicious mobile agents • Authenticating credentials • certificates and digital signatures • Access Control and Authorization • Reference monitor • security domains • policies • Software-based Fault Isolation • Java’s “sandbox” • Monitoring • auditing of agent’s activities • setting limits • Proxy-based approach to host protection • Code Verification - proof-carrying code

20. Threats to mobile agents • Denial of service • Unauthorized use or access of code/data • Unauthorized modification or corruption code/data • Unauthorized access, modification, corruption, or repeat of agent external communication

21. Possible attacks on mobile agents • Denial of service • Impersonation • Host • Agent • Replay • Eavesdropping • Communication • Code & data • Tamper attack • Communication • Code & data

22. Protection of mobile agents • Encryption • code • payload • Code obfuscation • Time-limited black-box security

23. Machine 1 Machine n Application: Technical reports GUI on home machine ... 1. Send agent 2. Send child agents / collect partial results 3. Return merged and filtered results Dynamically selected proxy site http://agent.cs.dartmouth.edu/

24. Wired network Application: Military Wireless Network Troop positions Technical specs Orders and memos http://agent.cs.dartmouth.edu/

25. Application: e-commerce VendorA Arbiter VendorB Bank Agent Yellow pages Agent http://agent.cs.dartmouth.edu/

26. Mobile agent systems

27. More examples and “bots” • Tryllian mobile agent system • Bots • mysimon.com • amazon.com - customer preferences

28. Current trends lead to mobile agents Increased need for personalization Server-side Information overload Mobile code to server or proxy “Customization” Too many unique, dispersed clients to handle Diversified population Proxy-based Multiple sites to visit Mobile Agents Bandwidth gap Avoid large transfers Mobile code to client Avoid “star” itinerary Mobile users and devices Disconnected Operation High latency

29. Applets Intranet Proxies that accept servlets Proxies provided by existing ISP’s Services that accept servlets Internet Mobile Agents Migrating to migrating code

30. Conclusion: Cons • Security is too big a concern • Overhead for moving code is too high • Not backward compatible with Fortran, C …. • Networks will be so fast, performance not an issue

31. Conclusion: Pros • A unifying framework for making many applications more efficient • Treats data and code symmetrically • Multiple-language support possible • Supports disconnected networks in a way that other technologies cannot • Cleaner programming model

32. For more information... • Mysimon.com • D’Agents: http://agent.cs.dartmouth.edu/ • Tryllian: http://www.tryllian.com • Aglets: http://www.trl.ibm.co.jp/aglets