Identifying MMORPG Bots: A Traffic Analysis Approach

MMORPGs have become extremely popular among network gamers.Despite their success,one of MMORPG's great- est challenges is the increasing use of game bots,i.e.,auto- playing 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,of- ten patrol game zones and question suspicious players.This practice,however,is labor-intensive and ine ffective.To ad- dress this problem,we analyze the tra ffic generated by hu- man players vs.game bots and propose solutions to auto- matically identify game bots. Taking Ragnarok Online ,one of the most popular MMOGs, as our subject,we study the tra ffic generated by mainstream game bots and human players.We find that their tra ffic is distinguishable by:1)the regularity in the release time of client commands,2)the trend and magnitude of tra ffic burstiness in multiple time scales,and 3)the sensitivity to network conditions.We propose four strategies and two in- tegrated schemes to identify bots.For our data sets,the conservative scheme completely avoids making false accusa- tions against bona fide players,while the progressive scheme tracks game bots down more aggressively.Finally,we show that the proposed methods are generalizable to other games and robust against counter-measures from bot developers