Content uploaded by Tyler Moore
All content in this area was uploaded by Tyler Moore on Dec 24, 2014
Content may be subject to copyright.
The Economics of Online Crime
Tyler Moore, Richard Clayton, and Ross Anderson
The economics of information security has recently become a thriving and
fast-moving discipline. This ﬁeld was kick-started in 2001 by the observa-
tion that poorly aligned incentives explain the failure of security systems at
least as often as technical factors (Anderson, 2001). As distributed computing
systems are assembled from machines controlled by principals with divergent
interests, microeconomic analysis and game-theoretic analysis become just as im-
portant for dependability as protocol analysis or cryptanalysis. The economic
approach not only provides a more effective way of analyzing straightforward
information-security problems such as privacy, spam, and phishing, but also gives
insights to scholars of system dependability, conﬂict, and crime. An annual Work-
shop on the Economics of Information Security (WEIS) was established in 2002.
The ﬁeld now involves over 100 active researchers; the subject has drawn together
security engineers, economists, and even lawyers and psychologists. For a survey of
security economics in general, see Anderson and Moore (2006).
This paper will focus on the subject of online crime, which has taken off as a
serious industry since about 2004. Until then, much of the online nuisance came
from amateur hackers who defaced websites and wrote malicious software in
pursuit of bragging rights. In the old days, electronic fraud was largely a cottage
yTyler Moore is a Postdoctoral Fellow, Center for Research on Computation and Society (CRCS),
Harvard University, Cambridge, Massachusetts. Richard Clayton is an Industrial Research Fellow
and Ross Anderson is Professor of Security Engineering, both at the Computer Laboratory,
University of Cambridge, Cambridge, England. Their e-mail addresses are 具tmoore@seas.
harvard.edu典,具Richard.Clayton@cl.cam.ac.uk典, and 具Ross.Anderson@cl.cam.ac.uk典, respectively.
Journal of Economic Perspectives—Volume 23, Number 3—Summer 2009—Pages 3–20
industry, local and inefﬁcient: a typical card fraudster ran a vertically-integrated
small business. For example, he might buy a card-encoding machine, get a job in
a shop where he could copy customers’ cards, and then go out at night to steal cash
from automatic teller machines (ATMs). Similarly, electronic fraud might have
involved a call-center employee collecting password data for use by an accomplice.
But now criminal networks have emerged—online black markets in which the
bad guys trade with each other, with criminals taking on specialized roles (Thomas
and Martin, 2006). Just as in Adam Smith’s pin factory, specialization has led to
impressive productivity gains, even though the subject is now bank card PINs rather
than metal ones. As shown in Table 1, someone who can collect bank card and PIN
data or electronic banking passwords can sell them online to anonymous brokers at
advertised rates of $0.40–$20.00 per card and $10–$100 per bank account (Syman-
tec, 2008). The information needed to apply for credit in someone else’s name,
such as name, social security number, and birthday, fetches $1 to $15 per set. The
brokers in turn sell the credentials to specialist cashiers who steal and then launder
A common modus operandi is for the cashier to transfer money from the
victim’s account to an account controlled by a “money mule.” The mules are
typically duped into accepting stolen money and then forwarding it. The cashiers
recruit them via job ads sent in spam e-mails or hosted on websites such as Craigslist
or Monster (Krebs, 2008a), which typically offer the opportunity to work from
home as a “transaction processor” or “sales executive.” Mules are told they will
receive payments for goods sold or services rendered by their employer and that
their job is to take a commission and forward the rest, using an irrevocable payment
service such as Western Union. After the mule has sent the money, the fraud is
discovered and the mule becomes personally liable for the funds already sent.
Cashiers also use stolen money to pump up the price of a penny stock in which they
have already invested; and they also launder money through online poker games
The collection of bank passwords has also become specialized. “Phishermen”
operate copies of genuine bank websites that encourage the unwary to log on so
that their bank account numbers, passwords, and other credentials can be copied.
These phishermen hire “spammers” to drive bank customers to their fake websites
by sending e-mails that purport to come from their bank. Both the spammers and
the phishermen use malicious software, or “malware,” which is designed to infect
the computers of people who run it; victims are duped into running it when they
download a seemingly innocuous program or visit one of approximately three
million infected websites (Provos, Mavrommatis, Rajab, and Monrose, 2008). The
emergence of a proﬁtable malware market means in turn that malware is no longer
written by teenagers seeking to impress their peers but by specialist ﬁrms with
budgets for R&D and testing. These ﬁrms in turn ensure that their products aren’t
detected by most antivirus software, and offer updates if they are (Schipka, 2007).
4 Journal of Economic Perspectives
One consequence is that while antivirus software previously detected most malware,
it now detects only a minority of it. Infected computers may log their users’
keystrokes to harvest credentials for electronic banking; they may also be recruited
into botnets, which we discuss next. While estimates vary, the general consensus is
that approximately 5 percent of computers worldwide are susceptible to malware
infection at any given time (House of Lords Science and Technology Committee,
2007); one security provider has estimated that 10 million computers are infected
with malware designed to steal online credentials (Panda Security, 2009).
With this new online crime ecosystem has come a new profession: the “botnet
herder”—a person who manages a large collection of compromised personal
computers (a “botnet”) and rents them out to the spammers, phishermen, and
other crooks. The computers in the botnet have been infected with malware that
lets the botnet herder operate them by remote control, just as if they were robots.
Nearly all e-mail spam is now sent by botnets. Many websites used by online
criminals are hosted on botnets, ranging from online pharmacies through the fake
banks used in phishing scams to the sham companies that “hire” money mules
(Moore and Clayton, 2008a). Blackmailers also rent botnets and have threatened to
overload bookmakers’ websites with botnet trafﬁc just before large sporting events;
in 2004, three Russians were arrested after extorting several hundred thousand
dollars in this way (Sullivan, 2004). A botnet was used to shut down parts of
Estonia’s infrastructure as a political protest (Lesk, 2007). Around ﬁve million
computers participated in botnets unbeknownst to their owners in the second half
of 2007 alone (Symantec, 2008).
Online criminals are also involved in many other types of fraud, from bogus
lotteries through stock scams to advance-fee frauds, and in other crimes such as the
Electronic Crime Figures
Underground economy advertised unit prices
Bank account credentials $10–$100 Symantec (2008)
Credit cards $0.40–$20 Symantec (2008)
Full identity (name, SSN, birthday, etc.) $1–$15 Symantec (2008)
Online auction account credentials $1–$8 Symantec (2008)
Number of compromised computers and websites
Computers participating in botnets 5 million Symantec (2008)
Computers infected with identity-theft malware 10 million Panda Security (2009)
Websites hosting phishing (fake bank) pages 116,000 Moore and Clayton (2009)
Websites infecting visitors with malware 3 million Provos et al. (2008)
U.K. online banking fraud (6/2007–5/2008) £36.5 million APACS (2008)
U.S. direct identity theft losses (2006) $2.8 billion Gartner (2006)
European damages caused by malware (2006) €9.3 billion Computer Economics (2007)
Tyler Moore, Richard Clayton, and Ross Anderson 5
distribution of images of child sexual abuse. Some ﬁgures estimating costs of online
crime are presented at the bottom of Table 1.
Thus far, the world has not coped well with the rapid growth and industrial-
ization of online wickedness. Banks often hide fraud losses, or even blame their
customers for fraud; and they hesitate to share information with other banks. Police
agencies have also ﬂoundered.
Online crime has many similarities with the economics of conventional crime,
the study of which has blossomed since Becker’s (1968) seminal work. But there are
some interesting differences, many of them driven by the global scale of online
crime. We ﬁnd a useful historical analogy two generations ago when criminals
started using cars. Suddenly a burglar could break into several houses in a town
where the police didn’t know him and be home in time for breakfast. It took the
police a generation to catch up, using national police networks and ﬁngerprint
databases. Online crime, like vehicle-assisted crime, will force big changes, both
because it is transnational and also because it consists of a high volume of low-value
offenses. Existing mechanisms for international police cooperation are designed
for rare serious crimes, such as murder and terrorism, while online crime is petty
crime committed on a global and industrial scale. Another difference is that
conventional crime is generally committed by marginal members of society, espe-
cially by young men suffering multiple deprivation or abusing drugs or alcohol. In
contrast, people with comparative advantage at online crime tend to be educated
and capable, but they live in societies with poor job prospects and ineffective
This paper begins by looking at the data on online crime. We then examine
the collective-action aspects: people who connect infected personal computers to
the Internet create negative externalities in that their machines may emit spam,
host phishing sites, and distribute illegal content. The Internet’s global, distributed
architecture leads to security being dominated by the weakest link, which exposes
the poor coordination among defenders both public and private. We present
empirical evidence of how agile attackers shift across national borders as earlier
targets wise up to their tactics, and discuss ways to improve law-enforcement
Finally, we will examine how defenders’ incentives affect the outcomes. An
interesting case study is to measure the average time required to remove different
types of offending content from the Internet. Phishing sites that directly imperson-
ate technology businesses, such as eBay, are typically knocked out within hours; sites
that impersonate banks typically vanish within a few days; but money-laundering
websites take far longer. They do not target a single bank, but spread their harm over
the whole banking industry so that no one pursues them with much vigor. We will also
show how the refusal of banks (and their contractors) to share information on phishing
websites slows removal signiﬁcantly and how a public-sector remedy is unlikely, at least
in the short term.
6 Journal of Economic Perspectives
Hard statistics on losses from online crime are hard to come by in most
countries. But without them, other ﬁgures—whether of vulnerabilities in computer
systems, number of botnets, or size of spam ﬂows—lack a grounded connection to
the real economy.
One problem is that many of the statistics on security failure are collected by
parties with an incentive to under- or overreport. For example, the anti-phishing
group PhishTank has boasted about the large number of sites it identiﬁes
(OpenDNS, 2007), when accounting for duplicates would reduce its reported total
several-fold (Moore and Clayton, 2007). The U.K. banking trade association APACS
(Association for Payment Clearing Services) provides another example; it asserted
a 726 percent increase in phishing attacks between 2005 and 2006, but only a
44 percent rise in losses (APACS, 2007). Governments, by contrast, often seek to
minimize crime statistics. In a particularly egregious case, the UK government
changed the rules so that fraud must be reported to the bank rather than to the
police. This change caused the fraud ﬁgures to drop to near zero and was strongly
criticized by a Parliamentary committee (House of Lords Science and Technology
Committee, 2007). Internet service providers also have an incentive to undercount:
they want to downplay the amount of bad trafﬁc emanating from their customers,
lest it affect their relationships with other Internet service providers.
But two approaches to measuring online crime do hold promise. Although
individual banks are usually keen to keep data on fraud losses private, countrywide
aggregation from banking data is possible. The Banque de France and APACS
publish aggregated annual loss ﬁgures for the sums lost by banks to phishing attacks
in France and the United Kingdom respectively, along with totals for theft through
automatic teller machines and other ﬁnancial fraud. As banks collect such statistics
for operational, internal control, and audit purposes, aggregating them nationally
can be straightforward. In a report we were commissioned to write on security
economics and the internal market for the European Commission (Anderson,
Bo¨hme, Clayton, and Moore, 2008), we recommended that other countries follow
the British and French lead in publishing nationally aggregated ﬁgures.
A different, and complementary, approach has emerged in many U.S. states
and is now being considered by the European Parliament: security-breach report-
ing laws. Under a California law enacted in September 2002 (California State
Senate, 2002), both public and private entities that conduct business in California
must notify affected individuals when personal data under their control has been
acquired by an unauthorized person. The law was intended to ensure that individ-
uals are given the opportunity to protect their interests following data theft, such as
when 45 million credit card numbers were stolen from T.J. Maxx’s information
The Economics of Online Crime 7
technology systems (Greenemeier, 2007). It was also intended to motivate compa-
nies to keep personal data secure; and Acquisti, Friedman, and Telang (2006)
found a statistically signiﬁcant negative impact on stock prices following a reported
breach. Romanosky, Telang, Acquisti (2008) examined identity theft reports ob-
tained from the Federal Communications Commission from 2002 to 2007. Using
time differences in the adoption of state breach disclosure laws, they found a small
but statistically signiﬁcant reduction in fraud rates following statewide law adop-
tion. Breach-disclosure laws also contribute data on security incidents to the public
domain. The California law has inspired further laws in at least 34 other states,
although their details vary.
Security breach notiﬁcation could be improved with a central clearinghouse
and some standardization of procedures. A clearinghouse would help to ensure
that all reported breaches can be located by the press, investors, researchers, and
sector regulators. Future U.S. or EU laws should also set minimum standards for
notiﬁcation; some U.S. companies have hidden notiﬁcations amongst lengthy
marketing material. Finally, notiﬁcation should include advice on what individuals
should do; some notiﬁcations by U.S. ﬁrms have puzzled or terriﬁed their recipi-
ents, rather than helped them with advice on risk reduction.
Some researchers have studied the new criminal markets directly. Researchers
from the Internet security ﬁrm Team Cymru have long documented online crime
(for example, Thomas and Martin, 2006). Franklin, Perrig, Paxon, and Savage
(2007) monitored the public chat channels used by online criminals to contact
each other, gathering extensive data on credit card fraud, spamming, phishing, and
the sale of compromised hosts. Kanich et al. (2008) went a step further. They
inﬁltrated a large botnet and altered the spam e-mails sent out so that they linked
to a benign duplicate website under the researchers’ control. They were able to
provide the ﬁrst independent answer to a long-standing question: how many people
respond to spam? It turns out that 28 sales resulted from 350 million spam e-mails
advertising pharmaceuticals—a conversion rate of 0.00001 percent. Such innova-
tive surveillance will continue to be necessary. Unfortunately, in many countries
(including the United Kingdom) such projects can only be carried out lawfully by
law enforcement agencies—many of whom lack the technical expertise or simply
don’t care. Indeed, many countries have passed information security laws that
probably do more to prevent security researchers from doing their jobs than to
tackle actual crime.
Without accurate information on online crime, it is hard for private markets to
provide incentives for more secure software. Akerlof’s (1970) model of the “market
for lemons” applies to many information security product and service markets. The
security of software is hard enough for its developers to ascertain, let alone their
customers; and consumers naturally refuse to pay a premium for quality they
8 Journal of Economic Perspectives
Interdependent Security and the Difﬁculty of Coordination
In many contexts, security depends on the efforts of many interdependent
principals. Hirshleifer (1983) told the story of Anarchia, an island whose ﬂood
defenses were built by individual landowning families and whose defense thus
depended on the weakest link—that is, the laziest family. He compared this to a city
whose protection against missile attack depended on the single best intercepting
shot, and showed that best-shot provides better defense than weakest-link. Varian
(2004) added a third case—where performance depends on the sum of the efforts
of all the defenders, as in a democracy where we pay taxes and hire soldiers—and
showed that this sum-of-efforts defense strategy is the best of all three.
Fixing online crime is hard because Internet security is often weakest-link.
Millions of personal computers have been recruited to botnets, and attackers are
spoilt for choice when selecting computers running out-of-date software to com-
promise. In addition, Internet insecurity is a bit like environmental pollution:
someone who connects an insecure computer to the Net is creating a negative
externality, as the computer can be used by others to attack third parties; there has
even been a suggestion of a cap-and-trade system for software quality (Camp and
Wolfram, 2004). The concentrated nature of the software industry, however, and its
success to date in disclaiming liability, may mean that such solutions are some way
off. Online malefactors also buy services from providers with the feeblest security
policies, or which turn a blind eye to misbehavior.
The weakest-link nature of much Internet security brings us to the fundamen-
tal issue of where we can ﬁnd, or create, effective control points. Responsibility for
prevention could be placed on computer owners, Internet service providers, soft-
ware suppliers, private security ﬁrms, law enforcement, or banks. Naturally, every
one of these stakeholders wants someone else to ﬁx the problem. Security is a
classic collective-action problem. How can we get the actors in the system to
respond to the social costs of online crime, not just the private costs?
A Central Role for Internet Service Providers
Internet service providers (ISPs) are unusually well placed to detect infection
because evidence of a user’s infection necessarily ﬂows over an ISP’s network. The
approximately 4,000 ISPs in the United States range in size from mom-and-pop
ﬁrms serving a few hundred customers in rural outposts to behemoths such as
AT&T, Verizon, AOL, and Comcast, which each provide online connectivity to
millions of households and businesses. Moreover, large ISPs have technical staff
who can detect and clean up infected computers, while domestic users and small
businesses are generally unable even to recognize when they are compromised.
ISPs are also uniquely placed to limit the external impact of an infected computer:
they control its Internet connection and can disconnect it if need be. Current best
practice is less drastic: it is to quarantine infected computers into a “walled garden”
Tyler Moore, Richard Clayton, and Ross Anderson 9
subnetwork from which they can access decontamination and software patches but
not much else.
The market provides incentives for some Internet service providers to take
action. An OECD study found that the strongest driver was the cost of customer
support—one medium-sized ISP reported 1–2 percent of its total revenue was spent
on handling security-related support calls (van Eeten and Bauer, 2008). Another
incentive is that a provider whose customers emit too much bad trafﬁc can ﬁnd its
peering arrangements with other companies damaged. However, very large ISPs are
effectively exempt from peer pressure as others cannot afford to cut them off.
Much of the world’s bad trafﬁc comes from the networks of these “too big to block”
Some particularly negligent providers attract disproportionate amounts of bad
business. For example, until 2007, a lot of the world’s malware was hosted by the
Russian Business Network, which ignored requests from international law enforce-
ment (The Economist, 2007). After the Russian Business Network suddenly went
ofﬂine in late 2007, malware distribution shifted elsewhere. In November 2008, a
journalist from the Washington Post persuaded upstream bandwidth providers to
shut off their connection to San Francisco-based McColo (Krebs, 2008b), which led
to a temporary fall of almost 70 percent in the volume of spam worldwide.
Apparently, many botnet herders had been using McColo to host their control
computers. And recently EstDomains, which had served as the primary domain
name registrar for malicious websites hosted by Russian Business Network (Krebs,
2008c), became the ﬁrst domain registrar to have its accreditation terminated by
the Internet Corporation for Assigned Names and Numbers (ICANN, 2008), the
not-for-proﬁt corporation that coordinates the Internet’s naming system.
However, attackers can often exploit the next weakest link in the Internet far faster
than defenders can knock them out. Moore and Clayton (2007) described how one
leading group of online fraudsters, the rock-phish gang, operates. It registers many
malicious web domain names to carry out attacks. Periodically, the gang picks a new
domain name registrar and becomes an active customer, registering hundreds of web
domains using false names and stolen credit cards. Because registrars will take down a
domain name quickly if it looks abusive—such as a misspelling of a bank’s name—the
rock-phish gang chooses domains that do not appear to violate any trademark. It may
take much longer to convince a naive registrar that an apparently innocuous domain
is in fact being used for criminal purposes.
Figure 1 presents scatter plots of phishing website lifetimes based on data
reported by Moore and Clayton (2007). The horizontal axis shows when the
phishing site was reported; the vertical axis shows how long it lasted. The gang
targeted Hong Kong domains ﬁrst in March 2007, and then after the Hong Kong
authorities wised up, they targeted Chinese domains in May 2007. Phishing sites on
.hk (Hong Kong) domains and .cn (China) domains lasted much longer in the ﬁrst
months after the gang began targeting each domain type than in later months.
10 Journal of Economic Perspectives
Other researchers also documented how websites hosting malware move from one
registrar to the next (Day, Palmen, and Greenstadt, 2008).
Educating registrars is a work in progress. A few large ﬁrms perform most
registrations (for example, GoDaddy, Network Solutions, register.com), but as with
Internet service providers, there are thousands of smaller companies too. The
Anti-Phishing Working Group’s Internet Policy Committee (2008) has set itself the
ambitious goal of educating all registrars about common threats, such as the
rock-phish gang, before they are targeted.
Policymakers should also give Internet service providers, especially the big
ones, a stronger incentive to stop infected computers attacking other users. For
example, in our report for the European Commission, we proposed ﬁxed statutory
damages against an ISP that does not act within a ﬁxed time period after being
notiﬁed of an infected computer on its network (Anderson, Bo¨hme, Clayton, and
Moore, 2008) At present, takedown speed varies hugely: the best ISPs remove
phishing sites in less than an hour, while others take weeks. Introducing a ﬁxed
minimum charge for not dealing with misbehaving websites after a reasonable
notice period, say three hours, would provide a useful nudge.
Statutory damages of this general form have been used effectively in the airline
industry, where the European Union has introduced them for airlines that deny
passengers boarding due to overbooking, cancellations, or excessive delays. A
passenger who can’t ﬂy can claim a ﬁxed amount (typically 250 euros) from the
airline, without having to produce hotel bills or other evidence of actual expenses.
The airline may then sue other parties (such as airports or maintenance contrac-
tors) to recover these damages where appropriate. Similarly, we envision that
Internet service providers would be able to recover damages from other negligent
parties. Another of our recommendations is that vendors of network-attached
Scatter Plot of Phishing Site Lifetimes over Time Based on the Domain Targeted
May June July August
Site lifetime (hours)
March April May June July August
Site lifetime (hours)
Source: Moore and Clayton (2007)
The Economics of Online Crime 11
consumer equipment should have to certify that it is “secure by default,” so if it
turns out not to be, then ISPs could seek redress without being frustrated by the
ubiquitous software liability disclaimers.
Movies and novels sometimes ascribe almost mythical abilities to computer
hackers and especially to successful gangs like rock-phish. Yet our analysis and data
suggest that the success of some of these gangs is as much strategic as technical: that
is, successful attackers are not writing brilliant software, but instead are exploiting
basic failings systematically. Ohm (2008) conﬁrms this analysis in a discussion of the
“myth of the Superuser”—people ascribe extraordinary capabilities to hackers
when the reality revealed by empirical analysis is much more straightforward.
Sharing Security Data among Take-Down Firms
Collecting timely, comprehensive data on the latest online vulnerabilities and
the currently compromised websites is essential for protecting consumers. How-
ever, many information security contractors that take down malicious websites on
behalf of their clients keep such data to themselves, arguing that the information
beneﬁts their ﬁrm’s competitive position. We have found that both the ﬁrms’
customers and consumers would beneﬁt if security contractors shared more data.
Back in the old days of the 1980s and 1990s, antivirus companies did not share
virus samples; instead, they boasted of how comprehensive their lists were. Trade
magazines published head-to-head comparisons of competing products, testing
whether one antivirus company like Dr. Solomon caught more viruses than another
one like Norton. In 1993, a series of press releases from the major companies
claimed that some new virus was being overlooked by the competition, and it ﬁnally
became clear that the overall effect of not sharing was damaging the industry. At
that year’s European Institute for Computer Antivirus Research (EICAR) confer-
ence, a meeting of the antivirus researchers led to an agreement that they would
share samples of viruses with their competitors. This sharing continues to this day,
improving the quality of protection available to consumers and businesses.
The anti-phishing industry has yet to learn this lesson. At its core lie specialist
contractors, such as Cyveillance, RSA, and MarkMonitor, who are hired by banks to
remove phishing websites and to suspend abusive domain names. These ﬁrms
compile “feeds” of ﬁshing sites—up-to-the minute lists of phishing page locations.
Moore and Clayton (2008b) analyzed six months of feeds from multiple sources,
including two anti-phishing contractors. In each case, many phishing websites were
known somewhere in the industry, but not to the company with the take-down
contract for the bank actually targeted by the site.
Figure 2 shows the ﬁndings for one large take-down company, called T
removed phishing sites on behalf of 54 client banks during a six-month period.
identiﬁed 9,008 of the sites impersonating its clients (represented by the
left circle), a further 5,962 sites were known to its competitors (the right circle). As
there could be other targets that neither T
nor its competitors knew about, T
missed at least 40 percent of its targets.
12 Journal of Economic Perspectives
Moore and Clayton approximate the costs of this situation relative to a more
cooperative alternative by examining website lifetimes. The sites only T
about are removed within 17 hours on average, while sites unknown to T
112 hours on average, around four days longer. In addition, of the 9,008 websites
did know about, 4,313 were identiﬁed by the other sources ﬁrst, at an average
of 50 hours before T
learned of them. The effect of such delays can be seen in the
lifetime ﬁgures: these websites remain for 56 hours on average, 39 hours longer
than sites known only to T
. Phishing site lifetimes could be greatly shortened if
take-down companies shared data, as the antivirus companies began to do 15 years
ago. Their clients would gain directly, and the companies could also beneﬁt—not
only from the increased revenue opportunities of having more work to do, but also
from being able to market a more valuable overall service. Moore and Clayton
(2008b) calculated that website lifetimes could drop by half or more given infor-
mation sharing and that for these two companies’ clients alone—on some fairly
rough estimates—around $330 million a year of fraud might be prevented by
As with the antivirus industry 15 years ago, sharing would have industry effects.
Take-down companies compete on a number of factors, including price, customer
service, speed of removal, and “feed comprehensiveness”—which is the industry
term for how widely they search the web for offending sites. Sharing data would
eliminate comprehensiveness as a competitive factor, which might have the nega-
tive effect of reducing incentives in this area (Olson, 2008). This objection could be
dealt with by compensating those who provided more data to the common pool
(Moore, 2008). Some well-established companies may view sharing as lowering the
barriers to entry. However, competition would then move to speed of removal,
Venn Diagram Depicting Take-Down Company T
’s Awareness of and Response to
Phishing Websites Impersonating Its 54 Client Banks during October 2007–March
Number of phishing websites Mean lifetime of phishing website (in hours)
Known to TAKnown to others
Known to TA
Known to others
Known to TAKnown to others
Known to TA
Known to others
Source: Moore and Clayton (2008b).
Tyler Moore, Richard Clayton, and Ross Anderson 13
price, and service, at which incumbents would also have an advantage. And by
increasing the number of sites that can be removed, the service itself would be
worth more to the banks.
In our view, most existing take-down companies would beneﬁt from sharing
feeds—that is, the gains from the service being worth more would outweigh the loss
of competition on comprehensiveness. The only likely losers would be the few
companies that specialize primarily in producing feeds. For the banks that are
customers of the take-down companies, greater feed sharing offers only beneﬁts.
How the Incentives of Defenders Affect Take-Down Speed
Many different types of bad online content—from copyright violations to child
sexual abuse images to phishing websites—are subject to take-down requests.
Moore and Clayton (2008a) obtained data on the lifetimes of several types of
websites, summarized in Table 2.
The lifetimes of questionable websites are heavily inﬂuenced by who has an
incentive to ﬁnd and complain about the offending material. Phishing websites are
removed fastest: banks are highly motivated to remove any website that imperson-
ates them. By contrast, other illegal activities such as online pharmacies do not
appear to be removed at all.
However, most banks focus on removing only those websites that attack them
directly. They ignore a key component of the phishing supply chain: mule recruit-
ment. As described earlier, phishermen recruit “money mules,” dupes who launder
stolen money, typically using Western Union transfers. Because the fraudulent
transfers are often reversed, the mule ends up out of pocket rather than the bank,
and so banks lack an adequate incentive to crack down on mule recruitment. Their
incentive is also dulled by a collective-action problem: it is hard to tell which bank
will suffer from any given mule-recruitment campaign.
Website Lifetimes by Type of Offending Content
Free web-hosting Jan. 2008 240 4.3 0
Compromised web servers Jan. 2008 105 3.5 0
Rock-phish domains Jan. 2008 821 70.3 33
Fast-ﬂux domains Jan. 2008 314 96.1 25.5
Mule-recruitment websites Mar. 07–Feb. 08 67 308.2 188
Fast-ﬂux online pharmacies Oct.–Dec. 2007 82 1370.7 1404.5
Child sexual abuse images Jan.–Dec. 2007 2585 719 288
Source: Moore and Clayton (2008a).
14 Journal of Economic Perspectives
Thus, even though mule recruitment websites harm banks directly, not one of
the banks or take-down companies actively pursues them. Typically, only vigilante
groups such as “Artists Against 419” attempt any removal, and even they treat these
websites as low priority because they see the mules as complicit in phishing. Finally,
regulators may have trained banks to see money laundering as an issue of due
diligence, rather than risk reduction; most money-laundering controls are aimed at
crimes like drug trafﬁcking in which the banks are not victims, and the incentives
there steer them towards minimal and mechanical compliance. Moore and Clayton
(2008a) found that mule-recruitment websites lasted 308 hours, far longer than
phishing websites that directly impersonate banks (4 to 96 hours). This is an
opportunity missed; the most rapid growth in spam late in 2008 has been for mule
recruitment, which strongly suggests that mule shortage had become an important
bottleneck in phishing operations.
Attack technology also affects take-down speed, but to a lesser extent. Naive
crooks host their websites on free services or individual compromised web servers,
which are easy for the contractors to take down; more sophisticated criminals such
as the rock-phish gang mentioned earlier use evasive techniques such as fast-ﬂux.
Moore and Clayton (2007) describe this scheme: websites are hosted dynamically
on a botnet, residing for just a few minutes on each computer and moving
elsewhere before the removal service can do anything. But our ﬁgures show that the
lifetime of an offending site is determined far more by the direct incentives that
defenders have to take it down than by the attack technology. For example, Moore
and Clayton (2008a) found that fast-ﬂux phishing websites are removed in
96 hours, but fast-ﬂux pharmacies are hardly removed at all (lasting nearly two
months on average).
Coordination of Law Enforcement
There are tens of thousands of law enforcement agencies worldwide; many of
them, even in developed countries, are fairly uninformed about computer crime.
What is speciﬁcally illegal varies from one country to another: the leading global
legal framework, the Council of Europe Convention on Cybercrime, has been
ratiﬁed by the United States but has yet to be ratiﬁed by a majority of European
Union member states.
Once nations have agreed on what is a crime, police forces will still have little
incentive to work together on globalized volume crime. Suppose a phisherman in
Russia sends out a million spams to random e-mail addresses. The largest police
force in Britain, London’s Metropolitan Police, might ﬁnd ten thousand of these
arriving in its area—London accounts for about 1 percent of global Internet use.
The Met will be tempted to say “Oh bother, let the FBI deal with it,” and focus on
local street crime instead. Most local police forces prioritize crime-ﬁghting by
asking how many local citizens are victims, how many are perpetrators, and how
serious is the damage locally. Using these criteria, it may be that few online
attackers will seem worth pursuing, even if in aggregate they are having an enor-
The Economics of Online Crime 15
mous effect. In the United Kingdom, for example, there are only two small police
units specializing in online fraud (the Dedicated Cheque and Plastic Crime Unit
and the Police Central e-crime Unit) and both rely on the banking industry for a
lot of their funding.
The barriers to cooperation are further raised by the fact that online crime
usually crosses national boundaries. Existing mechanisms for international police
cooperation are expensive and slow—designed to catch the occasional fugitive
murderer, but not for dealing with millions of frauds at a cost of a few hundred
dollars each. The problem is compounded by sensitivities about national sover-
eignty: each individual case is reviewed by diplomats to ensure it isn’t politically
sensitive. Our suggestion here is that, following the precedent of SHAEF (the
Supreme Headquarters Allied Expeditionary Force) in World War II and NATO
today, countries should maintain liaison ofﬁcers at a central command center that
decides what tasks to undertake, whereupon the liaison ofﬁcers relay requests to
their own countries’ forces. Such a permanent “joint operation” would deal with
the glacial speed of current arrangements and the lack of international agreement
on what to prioritize. The key is that countries must trust their liaison ofﬁcers to
assess which requests carry no political baggage and can be treated as straightfor-
ward police matters. We also need a mechanism to evolve a global strategy on
cybercrime priorities. This will require both operational feedback and democratic
Public versus Private Action
The one cybercrime issue that really catches the attention of politicians and
the popular media is websites that host images of child sexual abuse. Yet, curiously,
we found that these websites are removed much more slowly than almost any other
type of unlawful content. Their average lifetime of 719 hours is over 150 times that
of normal phishing sites, and more than twice that of even the mule-recruitment
websites. Why might this be?
During the 1990s, when the Internet came to public attention, policymakers
established “child pornography” as the one Internet evil that all governments could
agree to ban. In 29 countries, Internet service providers established hotlines to
identify and take down offending material. In the United Kingdom, the Internet
Watch Foundation (IWF) does this job and claims to remove child sexual abuse
images hosted in Britain within 48 hours; only 0.2 percent of such sites are now
hosted in the United Kingdom (Internet Watch Foundation, 2006). When the
websites are hosted in other countries, the IWF notiﬁes a local hotline or law
enforcement agency, but then takes no further action.
Hotline policies and effectiveness vary and few, if any, are as effective as the
Internet Watch Foundation. The U.S CyberTipline operated by the National
Center for Missing and Exploited Children (NCMEC) states that they issue
take-down notices to Internet service providers “when appropriate”; however,
through October 2008, NCMEC apparently only issued notices to the subset of
16 Journal of Economic Perspectives
ISPs that were actually members. A new U.S. law enacted in October 2008, the
Protect Our Children Act, may ﬁx this particular problem by making it com-
pulsory for all ISPs to register with NCMEC. Law enforcement responses also
vary. Typically, reports are passed to a national agency, which must then pass the
information to a local jurisdiction, which then contacts the responsible ISP. Law
enforcement budgets are always tight, and police forces will vary in their efforts
in challenging such websites depending on how salient the issue is at that time
in local politics.
Almost all other types of unlawful online material are dealt with on an
international basis, and borders are essentially immaterial to a capable, moti-
vated, private-sector ﬁrm seeking to have content taken down. However, the
police have been given a monopoly on dealing with child sexual abuse images
in many jurisdictions. In the United Kingdom, for example, simple possession
of such material is a strict-liability criminal offense, effectively preventing the
private sector from helping. (A company seeking to disable such material would
likely possess it, in at least an on-screen image, at some stage of a takedown
process.) Because the police have sole authority to pursue this material, juris-
diction becomes a signiﬁcant stumbling block, for the police do not operate
across national (or sometimes state or county) borders. The Internet Watch
Foundation told us that they would be “treading on other people’s toes” if they
contacted Internet service providers outside the United Kingdom and that they
“are not permitted or authorized to issue notices to take down content to
anyone outside the UK.” In contrast, with other kinds of online crime, banks,
take-down companies, and even vigilantes show great ﬂexibility in their willing-
ness to pursue distant materials.
Police forces do however have a role in combating online crime. For example,
we have noticed signiﬁcant recent consolidation within the botnet and spam
industries; as we noted, the takedown of McColo reduced spam worldwide by
70 percent when it broke the control that six large herders had over their botnets.
In our view, police resources would best be concentrated on busting these large
gangs, and the FBI with “Operation Bot Roast” is already moving in this direction.
Ongoing tasks such as website take-down are better left to appropriately incentiv-
ized private contractors.
Since about 2004, online crime has become organized and industrialized like
no other crime, with the possible exception of the drugs trade. Many of the
problems that banks and police forces face in controlling it already exist in
traditional law enforcement but are made more acute online by factors ranging
from network externalities to global scale. Unfortunately, crime looks set to be a
permanent feature of the online ecosystem and to create signiﬁcant costs for banks,
Tyler Moore, Richard Clayton, and Ross Anderson 17
citizens, service providers, and others. We have presented the results of a number
of recent research efforts that together explain how the online crime industry
works, why current enforcement efforts are feeble, and how they could be
With previous technology-driven crime innovations, from credit card fraud
to the use of getaway cars in bank robbery, it took some time to work out the
optimal combination of public and private security resources. Our analysis in
this paper suggests that signiﬁcant improvements are possible in the way we deal
with online fraud. Criminal networks do have particular vulnerabilities—such as
their money laundering operations. However, individual banks don’t target
money launderers because launderers attack the banking system as a whole, not
any individual bank. Perhaps the banks’ trade associations should target the
laundrymen. Banks also fail to get their security contractors to share data on
attacks where this could help them directly. This collective action problem is
best dealt with by private-sector information sharing, as it was 15 years ago in the
world of computer viruses. Finally, we suggest that the police should concen-
trate their efforts on the big phishing gangs.
To control online crime better, we need to understand it better. The key to this
understanding is not so much technology, but gaining an economic perspective of
the incentives faced by the different players.
yThe authors are grateful to Allan Friedman, Steven Murdoch, and Andrew Odlyzko, who
read this paper in draft and made helpful comments.
Acquisti, Alessandro, Allan Friedman, and
Rahul Telang. 2006. “Is There a Cost to Privacy
Breaches? An Event Study.” Paper presented at
the International Conference on Information
Systems (ICIS), Milwaukee, WI.
Akerlof, George A. 1970. “The Market for
‘Lemons’: Quality Uncertainty and the Market
Mechanism.” Quarterly Journal of Economics,
Anderson, Ross. 2001. “Why Information Se-
curity is Hard—An Economic Perspective.” Pro-
ceedings of the 17
Annual Computer Security Appli-
cations Conference, 358–65. IEEE Computer
Anderson, Ross, Rainer Bo¨hme, Richard Clay-
ton, and Tyler Moore. 2008. “Security Econom-
ics and the Internal Market.” European Network
and Information Security Agency. http://www.
Anderson, Ross, and Tyler Moore. 2006. “The
Economics of Information Security.” Science,
Anti-phishing Working Group Internet Policy
Committee. 2008. “Anti-Phishing Best Practices
Recommendations for Registrars.” An APWG In-
dustry Advisory. http://www.antiphishing.org/
APACS (Association for Payment Clearing
Services). 2007. “Card Fraud Losses Continue to
18 Journal of Economic Perspectives
Fall.” Press release, March 14. http://www.apacs.
APACS (Association for Payment Clearing
Services). 2008. “APACS Announces Latest
Fraud Figures” Press release, September 25.
Becker, Gary. 1968. “Crime and Punishment:
An Economic Approach.” The Journal of Political
Economy, 76(2): 169–217.
California State Senate. 2002. “Assembly Bill
No. 700.” http://info.sen.ca.gov/pub/01-02/
Camp, L. Jean, and Catherine D. Wolfram.
2004. “Pricing Security: A Market in Vulnerabil-
ities.” In Economics of Information Security, Vol. 12,
Advances in Information Security, ed. L. Jean Camp
and Stephen Lewis, 17–34. Boston: Kluwer Aca-
Computer Economics. 2007. “Malware Re-
port: The Economic Impact of Viruses, Spyware,
Adware, Botnets, and other Malicious Code.”
Day, Oliver, Brandon Palmen, and Rachel
Greenstadt. 2008. “Reinterpreting the Disclo-
sure Debate for Web Infections.” In Managing
Information Risk and the Economics of Security, ed.
M. Eric Johnson, 179–197. New York: Springer.
The Economist. 2007. “A Walk on the Dark
Side.” August 30.
Franklin, James, Adrian Perrig, Vern Paxon,
and Stefan Savage. 2007. “An Inquiry into the
Nature and Causes of the Wealth of Internet
Miscreants.” Proceedings of ACM Conference on
Computer and Communications Security (CCS), 375–
388. ACM Press.
Gartner. 2006. “Gartner Says Number of Phish-
ing E-Mails Sent to U.S. Adults Nearly Doubles in
Just Two Years.” Press release, November 9.
Greenemeier. 2007. “T.J. Maxx Parent Com-
pany Data Theft Is The Worst Ever.” Information
Week, March 29. http://www.informationweek.
Hirshleifer, Jack. 1983. “From Weakest-link to
Best-shot: The Voluntary Provision of Public
Goods.” Public Choice, 41(3): 371–386.
House of Lords Science and Technology Com-
mittee. 2007. Personal Internet Security, 5th Report of
2006–07. London: The Stationery Ofﬁce.
Internet Corporation for Assigned Names and
Numbers (ICANN). 2008. “Termination of Reg-
istrar EstDomains to Go Ahead.” November 12.
Internet Watch Foundation. 2006. “Half-yearly
Report.” July. http://www.iwf.org.uk/documents/
Kanich, Chris, Christian Kreibich, Kirill
Levchenko, Brandon Enright, Geoffrey M.
Voelker, Vern Paxson, Stefan Savage. 2008.
“Spamalytics: An Empirical Analysis of Spam
Marketing Conversion.” Proceedings of ACM Con-
ference on Computer and Communications Security
(CCS), 3–14. ACM Press.
Krebs, Brian. 2008a. “ ‘Money Mules’ Help Haul
Cyber Criminals’ Loot.” Washington Post. January 25.
Krebs, Brian. 2008b. “Major Source of Online
Scams and Spams Knocked Ofﬂine.” Blog titled
“Security Fix.” Washington Post, November 11.
Krebs, Brian. 2008c. “EstDomains: A Sordid
History and a Storied CEO.” Washington Post.
September 8. http://voices.washingtonpost.com/
Lesk, Michael. 2007. “The New Front Line:
Estonia under Cyberassault.” IEEE Security and
Privacy, 5(4): 76–79.
Moore, Tyler. 2008. “How Can We Co-operate
to Tackle Phishing?” October 27. http://www.
Moore, Tyler, and Richard Clayton. 2007. “Ex-
amining the Impact of Website Take-down on
Phishing.” Proceedings of the Anti-Phishing Working
Group eCrime Researchers Summit, 1–13.
Moore, Tyler, and Richard Clayton. 2008a.
“The Impact of Incentives on Notice and Take-
down.” In Managing Information Risk and the Eco-
nomics of Security, ed. M. Eric Johnson, 199–223.
New York: Springer.
Moore, Tyler, and Richard Clayton. 2008b.
“The Consequence of Non-cooperation in the
Fight against Phishing.” Proceedings of the Anti-
Phishing Working Group eCrime Researchers Summit,
Moore, Tyler, and Richard Clayton. 2009.
“Evil Searching: Compromise and Recompro-
mise of Internet Hosts for Phishing.” Lecture
Notes in Computer Science, vol. 5628, pp. 256–72.
Ohm, Paul. 2008. “The Myth of the Superuser:
Fear, Risk and Harm Online.” UC Davis Law
Review, 41(4): 1327–1402.
The Economics of Online Crime 19
Olson, Eric. 2008. “A Contrary Perspective—
Forced Data Sharing Will Decrease Performance
and Reduce Protection.” October 22. http://
OpenDNS. 2007. “OpenDNS Shares April 2007
PhishTank Statistics.” Press release, May 1. http://
Panda Security. 2009. “More than 10 Million
Worldwide Were Actively Exposed to Identity Theft
in 2008.” March 10. http://www.pandasecurity.com/
Provos, Niels, Panayiotis Mavrommatis, Mo-
heeb Abu Rajab, and Fabian Monrose. 2008. “All
Your iFRAMEs Point to Us.” Proceedings of the 17
USENIX Security Symposium, 1–15. USENIX Asso-
Romanosky, Sasha, Rahul Telang, and Ales-
sandro Acquisti. 2008. “Do Data Breach Disclo-
sure Laws Reduce Identity Theft?” Paper pre-
sented at the 7
Workshop on the Economics of
Information Security, Hanover, NH. Available at
Schipka, Maksym. 2007. “The Online Shadow
Economy: A Billion Dollar Market for Malware
Authors”. MessageLabs White Paper. http://www.
Sullivan, Bob. 2004. “Experts Fret over Online
Extortion Attempts.” MSNBC. November, 10.
Symantec. 2008. Symatec Global Internet Security
Threat Report, Vol. 13, Trends for July–December 07.
Thomas, Rob, and Jerry Martin. 2006. “The
Underground Economy: Priceless.” USENIX ;lo-
gin, 31(6): 7–16.
van Eeten, Michael J. G., and Johannes M.
Bauer. 2008. “The Economics of Malware: Secu-
rity Decisions, Incentives and Externalities.”
OECD Science, Technology and Industry Work-
ing Paper No. 2008/1.
Varian, Hal. 2004. “System Reliability and Free
Riding.” In Economics of Information Security, Vol.
12, Advances in Information Security, ed. L. Jean
Camp and Stephen Lewis, 1–15. Boston: Kluwer
20 Journal of Economic Perspectives