In computing,
phishing is a form of criminal activity using social
engineering techniques. Phishers attempt to fraudulently acquire sensitive
information, such as passwords and credit card details, by masquerading as a
trustworthy person or business in an electronic communication. Phishing is
typically carried out using email or an instant message. Attempts to deal with
the growing number of reported phishing incidents include legislation, user
training, and technical measures.
The first recorded mention of phishing is on the alt.2600 hacker newsgroup in
January 1996, although the term may have appeared even earlier in the print
edition of the hacker magazine 2600[1].
The term phishing is a portmanteau of password harvesting[2]
and alludes to the use of increasingly sophisticated lures to "fish" for users'
financial information and passwords; ph is a common leet replacement for
f[3].
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Early phishing on AOL
Those who would later phish on AOL during the 1990s originally used fake,
algorithmically generated credit card numbers to create accounts on AOL, which
could last weeks or even months. After AOL brought in measures in late 1995 to
prevent this, early AOL crackers resorted to phishing for legitimate AOL
accounts.
Phishing on AOL was closely associated with the warez community that
exchanged pirated software. A phisher might pose as an AOL staff member and send
an instant message to a potential victim, asking him to reveal his password[4].
In order to lure the victim into giving up sensitive information the message
might include text such as "verify your account" or "confirm billing
information". Once the victim had submitted his password, the attacker could
access and use the victim's account for criminal purposes, such as spamming.
Both phishing and warezing on AOL generally required custom-written programs,
such as AOHell. Phishing became so prevalent on AOL that they added a line on
all instant messages stating: "no one working at AOL will ask for your password
or billing information".
In 1997, AOL's policy enforcement with respect to phishing and warez became
stricter and forced pirated software off AOL servers. AOL simultaneously
developed a system to promptly deactivate accounts involved in phishing, often
before phishes (the victims of a "phish") could respond. Phishers temporarily
moved to AOL Instant Messenger (AIM), since they could not be banned from the
AIM server. The shutting down of the warez scene on AOL caused most phishers to
leave the service, and many phishers — often young teens — grew out of the
habit.
Recent phishing attempts
More recent phishing attempts have targeted the customers of banks and online
payment services. E-mails supposedly from the Internal Revenue Service have also
been used to glean sensitive data from U.S. taxpayers[5].
While the first such examples were sent indiscriminately in the hope of finding
a customer of a given bank or service, recent research has shown that phishers
may in principle be able to establish what bank a potential victim has a
relationship with, and then send an appropriate spoofed email to this victim[6].
Targeted versions of phishing have been termed spear phishing[7].
Social networking sites are also a target of phishing, since the personal
details in such sites can be used in identity theft[8].
Experiments show a success rate of over 70% for phishing attacks based on social
networks
[9].
Phishing techniques
Most methods of phishing use some form of technical deception designed to
make a link in an email appear to belong to the spoofed organization. Misspelled
URLs or the use of subdomains are common tricks used by phishers, such as this
example URL, http://www.yourbank.com.example.com/. One method of
spoofing links used web addresses containing the @ symbol, which were
used to include a username and password in a web URL (contrary to the standard[11]).
For example, the link http://www.google.com@members.tripod.com/ might
deceive a casual observer into believing that the link will open a page on
www.google.com, whereas the link actually directs the browser to a page on
members.tripod.com, using a username of www.google.com; were
there no such user, the page would open normally. This method has since been
closed off in the Mozilla[12]
and Internet Explorer[13]
web browsers, while Opera provides a warning message and the option not to
follow the link.
Some phishing scams use JavaScript commands in order to alter the address
bar. This is done either by placing a picture of the legitimate entity's URL
over the address bar, or by closing the original address bar and opening a new
one containing the legitimate URL[14].
In another popular method of phishing, an attacker uses a bank or service's
own scripts against the victim[15].
These types of attacks (known as cross-site scripting) are particularly
problematic, because they direct the user to sign in at their bank or service's
own web page, where everything from the web address to the security certificates
appears correct. In reality, the link to the website is crafted to carry out the
attack, although it is very difficult to spot without specialist knowledge. Just
such a flaw was used in 2006 against PayPal[16].
A further problem with URLs has been found in the handling of
Internationalized domain names (IDN) in web browsers, that might allow visually
identical web addresses to lead to different, possibly malicious, websites.
Despite the publicity surrounding the flaw, known as IDN spoofing[17]
(or a homograph attack[18]),
no known phishing attacks have yet taken advantage of it.
Not all phishing attacks require a fake website. In an incident in 2006[19],
messages that claimed to be from a bank told users to dial a phone number
regarding a problem with their bank account. Once the phone number was dialed,
prompts told users to enter their account numbers and PIN. The number was
provided by a Voice over IP provider.
Damage caused by phishing
The damage caused by phishing ranges from loss of access to email to
substantial financial loss. This style of identity theft is becoming more
popular, because of the ease with which unsuspecting people often divulge
personal information to phishers, including credit card numbers, social security
numbers, and mothers maiden names. There are also fears that identity thieves
can obtain some such information simply by accessing public records
[20].
Once this information is acquired, the phishers may use a person's details to
create fake accounts in a victim's name, ruin a victim's credit, or even prevent
victims from accessing their own accounts.
It is estimated that between May 2004 and May 2005, approximately 1.2 million
computer users in the United States suffered losses caused by phishing, totaling
approximately $929 million USD. U.S. businesses lose an estimated $2 billion USD
a year as their clients become victims.[21]
In the United Kingdom losses from web banking fraud — mostly from phishing —
almost doubled to £23.2m in 2005, from £12.2m in 2004[22],
while 1 in 20 users claimed to have lost out to phishing in 2005[23].
Anti-phishing
There are several different techniques to combat phishing, including
legislation and technology created specifically to target phishing.
Social responses
One strategy for combating phishing is to train users to deal with phishing
attempts. One newer phishing tactic, which uses phishing emails targeted at a
specific company, known as spear phishing, has been harnessed to train
users at various locations, including West Point Military Academy. In a June
2004 experiment with spear phishing, 80% of 500 West Point cadets who were sent
a fake email were tricked into revealing personal information[24].
Users who are contacted about an account needing to be "verified" can take
steps to avoid phishing attempts, by contacting the company that is the subject
of the email to check that the email is legitimate, or by typing in a trusted
web address for the company's website into the address bar of their browser, to
bypass the link in the suspected phishing message[25].
Nearly all legitimate email messages from companies to their customers will
contain an item of information that is not readily available to phishers. Some
companies, like PayPal, always address their customers by their username in
emails, so if an email addresses a user in a generic fashion ("Dear PayPal
customer") it is likely to be an attempt at phishing[26].
Emails from banks and credit card companies will often include partial account
numbers. Therefore, one should always be suspicious if the message does not
contain specific personal information. Phishing attempts in early 2006, however,
used such highly personalized information, making it unsafe to rely on personal
information alone as a sign that a message is legitimate[27].
Further, another recent study concluded in part that the presence of this
information does not significantly affect the success rate of phishing attacks
[28],
suggesting that most users do not pay attention to such details anyway.
The Anti-Phishing Working Group, an industry and law enforcement association,
has suggested that conventional phishing techniques could become obsolete in the
future as people are increasingly aware of the social engineering techniques
used by phishers.[29]
They propose that pharming and other uses of malware will become more common
tools for stealing information.
Technical responses
Anti-phishing software is available that may identify phishing contents on
websites, act as a toolbar that displays the real domain name for the visited
website, or spot phishing attempts in email. Both Microsoft's new IE7 browser
and Mozilla's Firefox 2 (code-named Bon Echo) include a form of anti-phishing
technology, by which a site may be checked against a list of known phishing
sites. If the site is suspect the user is warned, although not prevented from
visiting it[30][31].
Firefox 2 uses Google anti-phishing software, which may also be installed under
IE6. Spam filters also help protect users from phishers, because they reduce the
number of phishing-related emails that users receive.
OpenDNS offers free DNS servers that will automatically block phishing sites.
It works transparently with any operating system and any web browser[32].
Sites have added verification tools that allow users to see a secret image
that the user selected in advance; if the image does not appear, then the site
is not legitimate. Bank of America use this together with challenge questions,
which ask the user for information that should be known only to the user and the
bank
[33]. This feature (and other forms of two-way authentication and
two-factor authentication) is still susceptible to attack, such as that suffered
by Scandinavian bank Nordea in late 2005[34].
Several companies offer banks and other entities likely to suffer from
phishing scams 24/7 services to monitor, analyze and assist in shutting down
phishing websites[35].
Legal responses
On January 26, 2004, the FTC (Federal Trade Commission) filed the first
lawsuit against a suspected phisher. The defendant, a Californian teenager,
allegedly created and used a webpage designed to look like the America Online
website, so that he could steal credit card numbers[36].
Other countries have followed the lead of the U.S. by tracing and arresting
phishers. A phishing kingpin, Valdir Paulo de Almeida, was arrested in Brazil
for leading one of the largest phishing crime rings, which in 2 years stole
between $18 and $37 million USD
[37]. UK
authorities jailed two men in June 2005 for their role in a phishing scam
[38],
in a case connected to the USSS Operation Firewall, which targeted notorious
"carder" websites
[39]. In 2006
eight people were arrested by Japanese police on suspicion of phishing fraud by
creating bogus Yahoo Japan Web sites, netting themselves 100 million yen ($870
thousand USD)[40].
In the United States, Democratic Senator Patrick Leahy introduced the
Anti-Phishing Act of 2005 on March 1, 2005. The federal anti-phishing bill
proposes that criminals who create fake web sites and spam bogus emails in order
to defraud consumers could receive a fine up to $250,000 and receive jail terms
of up to five years.[41]
Microsoft has also joined the effort to crack down on phishing. On March 31,
2005, Microsoft filed 117 federal lawsuits in the U.S. District Court for the
Western District of Washington. The lawsuits accuse "John Doe" defendants of
using various methods to obtain passwords and confidential information. March
2005 also saw Microsoft partner with the Australian government to teach law
enforcement officials how to combat various cyber crimes, including phishing[42].
Microsoft announced a planned further 100 lawsuits outside the U.S. in March
2006[43].
AOL reinforced its efforts against phishing[44]
in early 2006 with three lawsuits[45]
seeking a total of $18 million USD under the 2005 amendments to the Virginia
Computer Crimes Act[46][47].
