On Click Fraud Simone Soubusta, Düsseldorf Most of the information and services on called click fraud, which this paper will Internet advertising is getting more the web come at no cost to the user. The examine in detail. and more important. As in every publisher or webmaster, on the other growing line of business, criminals hand, has to pay to provide them. In try to profit from that growth. They order to profit from their complimentary 1.3 structure of the Article do so by manipulating Pay-Per-Click services, webmasters rent out space on (PPC) adverts with artificially gener- their websites to advertisers. This is the Chapter 2 introduces the reader to the ated clicks, a process which is known main means of covering the costs of pro- concept of click fraud against the back- Düsseldorfer Informationswissenschaftas Click Fraud (CF). CF is not diffi- viding online services nowadays. The ground of Pay-Per-Click advertising, fol- cult to commit and, consequently, it most famous example of this phenom- lowed by a short look at the legal rami- could threaten the existence of com- enon is probably Google. The search en- fications. Chapter 3 expounds how click panies like Google. At present, there gine accumulated considerable wealth by fraud is committed. An explanation of seems to be no way to either detect auctioning off advertising space next to how a click can be faked is followed by or prevent CF. It can, however, be al- their search results. two different techniques that are used together avoided by switching from Advertising plays an important role for to avoid detection: using a network of hi- PPC to other advertising schemes like every company. “Most businesses oper- jacked computers (a so-called botnet) to Cost-Per-Action. ate with an advertising budget of 2-5 per- commit click fraud, and making visitors cent of their previous year’s gross sales” of a website unintentionally assist in the (Egelhoff, n.d.). Since its inception, ad- fraud. Chapter 4 presents different ways Über Klickbetrug vertising has thrived on mass media like to detect click fraud, as well as ways to Internetwerbung wird immer wichti- newspapers and TV, where an ad could prevent click fraud altogether. Finally, ger. Wie in jeder Wachstumsbranche reach a wide audience. It comes as no chapter 5 concludes the article with a versuchen auch hier Kriminelle von surprise, then, that it has found the web look at its result. (see Fig. 1) diesem Wachstum zu profitieren. a suitable playground. Dies ist durch die Manipulation von Pay-Per-Click (PPC) Werbeanzeigen 2 What is click Fraud? mithilfe künstlich produzierter Klicks 1.2 cyber crime möglich – eine Vorgehensweise, die In the past, online advertising used the The rise of the internet has also brought Cost-Per-Impression model to charge for als Klickbetrug (Click Fraud) bekannt a completely new kind of crime: cyber advertisements. The cost per impres- ist. Klickbetrug ist nicht schwierig crime. The most well-known type of cyber sion is often measured in Cost Per Mile und könnte daher die Existenz von crime is Phishing, which means stealing (CPM), that is, the cost of one thousand Firmen wie Google bedrohen. Zur sensitive information online. This can be impressions of the ad. This advertising Zeit scheint es keine Möglichkeit zu anything from user name/password com- model was based on traditional TV and geben, Klickbetrug zu entdecken oder binations to credit card information and print advertising, where the advertiser is zu verhindern. Man kann Klickbetrug the troublesome social security number also charged on the basis of the number jedoch vermeiden, indem man PPC in the U.S. The criminal gains this infor- of times that the ad is viewed. Cost- Werbung durch eine andere Berech- mation by masquerading as an authority. Per-Impression is the preferred model of nungsgrundlage, wie z. B. Cost-Per- In order to gain access to the PIN/TAN publishers (webmasters), because they Action, ersetzt. combination of a user’s bank account, for are paid regardless of the effectiveness example, the criminal might write an e- of an ad. However, search engines such mail to the client, in which he pretends to as Google have given rise to the Pay-Per- be the bank itself. He presents the user Click (PPC) model of online advertising. 1 Introduction with a link that allegedly leads to the In this type of arrangement, advertis- bank’s online banking login page, where ers pay a certain amount of money to 1.1 Internet Advertising the user is asked to log in for ‘mainte- the publisher for every click on their ad It is a truth universally acknowledged nance reasons’ or something similar, but (which leads to the advertiser’s website). that the World Wide Web (WWW) has in reality the link leads to the phisher’s That is to say, the costs are performance- revolutionised our planet. Today the web website (which imitates the look and feel dependent. Consequently, the model is allows us to communicate with people of the bank’s site), allowing him to steal favoured by advertisers, who get an in- nearly anywhere in the world – and, in- the information and, therefore, the user’s terested visitor to their website for the deed, with billions of people at once. It money. Two other types of cyber crime money they pay. has changed the way we think, as well are credit card fraud, which the internet In particular, Google’s AdWords and Ad- as the way we do business. But the web has made infinitely easier to commit, and Sense (see Fig. 1 and 2) services have is not only a means of communication, spam, which doesn’t warrant further ex- added to the widespread use of PPC. it also contains a wealth of knowledge. planation. With AdWords, advertisers bid in an auc- Since the rise of the search engines, huge However, there is another kind of cyber tion for the placement of their ad next to amounts of information have become crime that the general public is not well the search results for a chosen keyword readily accessible. The known web alone acquainted with, but which is nonethe- (or a combination of keywords). This form spans several billion pages. less detrimental to many people: so- of advertising is also known as sponsored 136 59(2008)2, 136-141 Click Fraud Figure 1. Google AdWords. search. The obvious advantage for adver- perform this task himself or use more so- charged for fraudulent clicks as well as tisers is that the user who sees the ad- phisticated means (see below). for actual ones (Hadjinian, 2006). vertisement is already interested in the Publisher click fraud is, as the name in- Publisher click fraud is, in most cases, topic that is connected to the keyword dicates, performed by the publisher of simply a breach of contract. The Terms (since he searched for it), hence there is an ad, that is, by the owner of the web- of Service of Google’s AdSense program, a high chance that he is also interested site on which the ad (or, indeed, multiple for example, state: “You shall not, and in the product or service that is adver- ads) is displayed. It is committed solely shall not authorize or encourage any third tised next to it. A user who searches for for monetary gain. Since the publisher is party to: (i) directly or indirectly generate the term camera, for example, might be paid for every click on an ad, it is in his in- queries, Referral Events, or impressions shown an advertisement for a camera by terest to receive a high number of clicks. of or clicks on any Ad, Link, Search Re- Canon. In addition, the user also profits Thus, the fraudster artificially increases sult, or Referral Button through any au- from this targeted advertising, since he is the number of clicks in order to make tomated, deceptive, fraudulent or other only shown ads for products he likely has more money. Harmless dilettantes do this invalid means, including but not limited an interest in. by clicking on the ads themselves or by to through repeated manual clicks, the AdSense, on the other hand, is an adver- asking their friends to do so. Professional use of robots or other automated query tising network in which Google acts as fraudsters, on the other hand, either out- tools and/or computer generated search a commissioner. Similar to AdWords, ad- source the job to armies of ‘clickers’ in requests, and/or the unauthorized use of vertisers bid on certain keywords. Google India (Vidyasagar, 2004) or China, or they other search engine optimization services then automatically analyses the content automate the process entirely. This paper and/or software; [...] (iii) frame, minimize, of websites that have signed up as pub- will concern itself primarily with the lat- remove or otherwise inhibit the full and lishers for AdSense and places the ad ter option. complete display of any Web page ac- on those websites that contain content According to Noogie C. Kaufmann from cessed by an end user after clicking on which is closely related to the keyword. the University of Münster, competitor any part of an Ad (“Advertiser Page”), Every time someone clicks on such an ad, click fraud, as described above, is illegal any Search Results Page, or any Refer- the website owner gets a percentage of under German law since it violates § 4 Nr. ral Page; (iv) redirect an end user away the proceeds which Google receives from 10 UWG (purposeful hindrance of com- from any Advertiser Page, Search Results the advertiser, and the rest is Google’s petitors) and § 826 BGB (immoral deliber- Page, or Referral Page; provide a version commission.