EURASIP Journal on Advances in Signal Processing
Volume 2009 (2009), Article ID 797159, 22 pages
doi:10.1155/2009/797159
Research Article

Identifying MMORPG Bots: A Traffic Analysis Approach

Kuan-Ta Chen,1 Jhih-Wei Jiang,2 Polly Huang,3 Hao-Hua Chu,2 Chin-Laung Lei,3 and Wen-Chin Chen2

1Institute of Information Science, Academia Sinica, Taipei 115, Taiwan
2Department of Computer Science and Information Engineering, National Taiwan University, Taipei 106, Taiwan
3Department of Electrical Engineering, National Taiwan University, Taipei 106, Taiwan

Received 10 April 2008; Accepted 8 September 2008

Academic Editor: Rocky Chang

Copyright © 2009 Kuan-Ta Chen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Massively multiplayer online role playing games (MMORPGs) have become extremely popular among network gamers. Despite their success, one of MMORPG's greatest challenges is the increasing use of game bots, that is, autoplaying game clients. The use of game bots is considered unsportsmanlike and is therefore forbidden. To keep games in order, game police, played by actual human players, often patrol game zones and question suspicious players. This practice, however, is labor-intensive and ineffective. To address this problem, we analyze the traffic generated by human players versus game bots and propose general solutions to identify game bots. Taking Ragnarok Online as our subject, we study the traffic generated by human players and game bots. We find that their traffic is distinguishable by 1) the regularity in the release time of client commands, 2) the trend and magnitude of traffic burstiness in multiple time scales, and 3) the sensitivity to different network conditions. Based on these findings, we propose four strategies and two ensemble schemes to identify bots. Finally, we discuss the robustness of the proposed methods against countermeasures of bot developers, and consider a number of possible ways to manage the increasingly serious bot problem.