Detecting Multiple Seller Collusive Shill Bidding

Journal of Computers, 2007

Shill bidding is where spurious bids are introduced into an auction to drive up the final price for the seller, thereby defrauding legitimate bidders. Trevathan and Read presented an algorithm to detect the presence of shill bidding in online auctions. The algorithm observes bidding patterns over a series of auctions, and gives each bidder a shill score to indicate the likelihood that they are engaging in shill behaviour. While the algorithm is able to accurately identify those with suspicious behaviour, it is designed for the instance where there is only one shill bidder. However, there are situations where there may be two or more shill bidders working in collusion with each other. Colluding shill bidders are able to engage in more sophisticated strategies that are harder to detect. This paper proposes a method for detecting colluding shill bidders, which is referred to as the collusion score. The collusion score, either detects a colluding group, or forces the colluders to act individually like a single shill, in which case they are detected by the shill score algorithm. The collusion score has been tested on simulated auction data and is able to successfully identify colluding shill bidders.

Computer and Information Science, 2015

Human cheating has been a barrier to establishing trust among e-commerce users, throughout the last two decades. In particular, in online auctions, since all the transactions occur among anonymous users, trust is difficult to establish and maintain. Shill bidding happens when bidders bid exclusively to inflate (in forward auctions) or deflate (in reverse auctions) prices in online auctions. At present, shill bidding is the most severe and persistent form of cheating in online auctions, but still there are only a few or no established techniques for shill defense at run-time. In this paper, I evaluate the strengths and weaknesses of existing approaches to combating shill bidding. I also propose the ShillFree1 auction system to secure and protect auction systems from shill bidders for both forward and reverse auctions. More precisely, by using a variety of bidding behavior and user history, proposed auction system prevents, monitors and detects shill activities in real time. Moreover, to detect shilling thoroughly I propose IP tracking techniques. The system also takes necessary actions against shill activities at run-time. The experimental results demonstrate that, by prevention, detection and response mechanisms, the proposed auction system keeps the auction users secured from shill bidding and therefore establishes trust among online auction users.

Proceedings of the 51st Hawaii International Conference on System Sciences, 2018

Online auctions are highly susceptible to fraud. Shill bidding is where a seller introduces fake bids into an auction to drive up the final price. If the shill bidders are not detected in run-time, innocent bidders will have already been cheated by the time the auction ends. Therefore, it is necessary to detect shill bidders in real-time and take appropriate actions according to the fraud activities. This paper presents a real-time shill bidding detection algorithm to identify the presence of shill bidding in multiple online auctions. The algorithm provides each bidder a Live Shill Score (LSS) indicating the likelihood of their potential involvement in price inflating behavior. The LSS is calculated based on the bidding patterns over a live auction and past bidding history. We have tested our algorithm on data obtained from a series of realistic simulated auctions and also commercial online auctions. Experimental results show that the real-time detection algorithm is able to prune the search space required to detect which bidders are likely to be potential shill bidders.

Journal of theoretical and applied electronic commerce research

Online auctions are a popular and convenient way to engage in ecommerce. However, the amount of auction fraud has increased with the rapid surge of users participating in online auctions. Shill bidding is the most prominent type of auction fraud where a seller submits bids to inflate the price of the item without the intention of winning. Mechanisms have been proposed to detect shill bidding once an auction has finished. However, if the shill bidder is not detected during the auction, an innocent bidder can potentially be cheated by the end of the auction. Therefore, it is essential to detect and verify shill bidding in a running auction and take necessary intervention steps accordingly. This paper proposes a run-time statistical algorithm, referred to as the Live Shill Score, for detecting shill bidding in online auctions and takes appropriate actions towards the suspected shill bidders (e.g., issue a warning message, suspend the auction, etc.). The Live Shill Score algorithm also uses a Post-Filtering Process to avoid misclassification of innocent bidders. Experimental results using both simulated and commercial auction data show that our proposed algorithm can potentially detect shill bidding attempts before an auction ends.

Trust is difficult to establish in online auctions since transactions occur among complete strangers. The Internet Fraud Complaint Center shows that auction fraud is the highest rate of crime in online activities. Nowadays, shill bidding is the most severe and persistent fraud for online auction users. Considering the strengths and weaknesses of existing works on , in this paper, we propose a reliable software architecture to secure and protect auction systems from shill bidders for both forward and reverse auctions. More precisely our auction system monitors and detects shill bidding in run-time as well as takes necessary actions against shill bidding .

2019

Online auctions have become one of the most popular and convenient buying and selling media in e-commerce. However, the amount of auction fraud increases with the popu- larity of online auctions. This thesis examines one of the most severe types of auction fraud, referred to as shill bidding, where fake bids are used to arti cially in ate an item's nal price. Shill bidding is strictly prohibited in online auctions because it forces honest bidders to pay more for their products. Researchers have proposed several mechanisms to detect shill bidding once an auction has nished. However, if shill bidding is not detected during an auction, an innocent bidder (i.e., the winner of the auction) can potentially be cheated by the end of the auction. Therefore, it is necessary to detect and verify potential shill bidding in real-time (i.e., while an auction is in progress). This thesis proposes and implements several novel techniques for combating shill bidding in real-time. The e ectiveness...

Proceedings of the 35th Annual Hawaii International Conference on System Sciences

The online implementation of traditional business mechanisms raises many new issues not considered in classical economic models. This partially explains why online auctions have become the most successful but also the most controversial Internet businesses in the recent years. One emerging issue is that the lack of authentication over the Internet has encouraged shill bidding, the deliberate placing of bids on the seller's behalf to artificially drive up the price of the seller's auctioned item. Private-value English auctions with shill bidding can result in a higher expected seller profit than other auction formats [1], violating the classical revenue equivalence theory. This paper analyzes shill bidding in multi-round online English auctions and proves that there is no equilibrium without shill bidding. Taking into account the seller's shills and relistings, bidders with valuations even higher than the reserve will either wait for the next round or shield their bids in the current round. Hence, it is inevitable to redesign online auctions to deal with the "shiller's curse."

4th International Conference on Information Technology: New Generations, 2007

Shill bidding is where fake bids are introduced into an auction to drive up the final price for the seller, thereby defrauding legitimate bidders. Although shill bidding is strictly forbidden in online auctions such as eBay, it is still a major problem. This paper presents a software bidding agent that follows a shill bidding strategy. The malicious bidding agent was constructed to aid in developing shill detection techniques. The agent incrementally increases an auction’s price, forcing legitimate bidders to submit higher bids in order to win the item. The agent ceases bidding when the desired profit from shilling has been attained, or in the case that it is too risky to continue bidding without winning the auction. The agent’s ability to inflate the price has been tested in a simulated marketplace and experimental results are presented. This is the first documented bidding agent that perpetrates auction fraud. We do not condone the use of the agent outside the scope of this research.

2008

Shill bidding is the act of using bids in an online auction to drive up the final price for the seller, thereby defrauding legitimate bidders. While 'shilling' is recognized as a problem and shill bidding is strictly forbidden in online auctions, presently there is little to no established means of defense against shills. This paper presents a software bidding agent that follows a shill bidding strategy. The agent incrementally increases an auction's price, forcing legitimate bidders to submit higher bids in order to win the item. The agent ceases bidding when the desired profit from shilling has been attained, or in the case that it is too risky to continue bidding without winning the auction. Its ability to inflate the price has been tested in a simulated marketplace and experimental results are presented. Furthermore, the agent is used to assist in developing algorithms to detect the presence of shill bidding in online auctions.

2008