1. Decoy Router Placement Jacopo Cesareo, Michael Schapira, and Jennifer Rexford Princeton University

2. Decoy Router Placement Decoy router along the path to decoy destination … directs traffic to the covert destination 2 client decoy destination covert destination decoy router

3. Placement Problem Given clients, destinations, and paths –Clients: {c i } –Decoy destinations: {d j } –Paths: {P ij } from client c i to decoy destination d j Select K decoy routers –Decoy routers: {r k } from a set of candidates R To maximize –# client/decoy pairs that traverse a decoy router, or –# clients traversing a decoy router for some decoy dest 3 c1c1 c2c2 c3c3 d1d1 d2d2 P 11 P 32

4. Greedy Placement Algorithm Computational limits –NP hard to find the optimal solution –Best approximation has ~2/3 bound Heuristic based on “popularity” –# of (c i, d j ) pairs traversing the router, or –# of c i traversing the router to reach some decoy dest Greedy algorithm achieves the ~2/3 bound! –Select the most popular candidate –Remove all parties it “covers” –Recompute the popularities –Repeat until K routers are chosen 4 c1c1 c2c2 c3c3 d1d1 d2d2 P 11 P 32

5. Initial Experiment Autonomous System (AS) level model –RouteViews measurements of interdomain routing –CAIDA inferences of AS-level relationships –Simulation of AS-level routing decisions Example experiment –Clients: all ASes located in Australia –Decoy destinations: ASes for Amazon and eBay –Candidate decoy routers: all ASes outside Australia Results for two scenarios –# of client/decoy pairs that traverse a decoy router, or –# of clients that traverse a decoy router for some decoy 5

6. Good Placement  Good Coverage 6

7. Conclusions and Future Work Good coverage with relatively few decoy routers –Effective placement algorithm with good bound –Clients concentrated through a few regional ISPs –A few large ISPs provide most wide-area connectivity Future work –Wider range of clients and decoy destinations –Direct measurements of AS paths and router-level paths –Selection of decoy destinations given the decoy routers –Reactions of adversaries to circumvent decoy routers 7

8. Backup Slides 8

9. Decoy Router ASes For clients in Australia –Decoy routers for clients  Cogent, AOL, NTT, ReachNetworks, Verizon  174, 1668, 2914, 4637, 701 –Decoy routers for client/decoy-destination pairs  Singapore Telecom, ReachNetworks, Tata Communications, Cogent, Level3, Telecom New Zealand, NTT, KDDI, NetAccess For clients in China –Decoy routers for clients  Cogent, SwissCom, NetAccess, … –Decoy routers for client/decoy-destination pairs  Cogent, Qwest, SwissCom, AOL, NetAccess, KDDI, Verizon, Deutsche Telekom, … 9

10. Placement Algorithm: China 10