Definition for "PHISHING"
(source :
wikipedia)
In computing, phishing is a 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, although phone contact has been used as well. 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.online-service.america-online Usenet newsgroup on January 2, 1996, although the term may have appeared even earlier in the print edition of the hacker magazine 2600. The term phishing is a variant of fishing, probably influenced by phreaking, and alludes to the use of increasingly sophisticated lures to "fish" for users' financial information and passwords. The word may also be linked to leetspeak, in which ph is a common substitution for f. The popular theory that it is a portmanteau of password harvesting is an example of folk etymology.
Phishing techniques
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. 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. Targeted versions of phishing have been termed spear phishing. Social networking sites are also a target of phishing, since the personal details in such sites can be used in identity theft. Experiments show a success rate of over 70% for phishing attacks on social networks. In late 2006 a computer worm took over pages on MySpace and altered links to direct surfers to websites designed to steal login details.
Phishing techniques
- Link manipulation - Most methods of phishing use some form of technical deception designed to make a link in an email (and the spoofed website it leads to) 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/. Another common trick is to make the anchor text for a link appear to be a valid URL when the link actually goes to the phishers' site.
An old method of spoofing links used links containing the @ symbol, originally intended as a way to include a username and password in a web link (contrary to the standard). 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: the page opens normally, regardless of the username supplied. Such URLs were disabled in Internet Explorer, while the Mozilla and Opera web browsers opted to present a warning message and give users the option of continuing to the site or cancelling. 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 or a homograph attack, no known phishing attacks have yet taken advantage of it. Phishers have taken advantage of a similar risk, using open URL redirectors on the websites of trusted organizations to disguise malicious URLs with a trusted domain.
- Website forgery - Website forgeryOnce the victim visits the website the deception is not over. 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. In another popular method of phishing, an attacker uses a trusted website's own scripts against the victim. 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. A Universal Man-in-the-middle Phishing Kit, discovered by RSA Security, provides a simple to use interface that allows a phisher to convincingly reproduce any website and capture any log in details entered at the fake site.
- Phone phishing - Not all phishing attacks require a fake website. In an incident in 2006, 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 (owned by the phisher, and provided by a Voice over IP provider) was dialed, prompts told users to enter their account numbers and PIN.
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Technical responses
Helping users identify legitimate sites - Since phishing is based on impersonation, preventing it depends on users having some reliable way to identify the sites they are dealing with. For example, some anti-phishing toolbars display the real domain name for the visited website. The petname extension for Firefox lets users type in their own labels for websites, so they can later recognize when they are back at the correct site. If the site is a suspect, the software may either warn the user or block the site outright.
Alerting users to fraudulent websites - Another popular approach to fighting phishing is to maintain a list of known phishing sites and to check websites against the list. Microsoft's new IE7 browser, Mozilla Firefox 2.0, and Opera all contain this type of anti-phishing measure. Firefox 2 uses Google anti-phishing software, which may also be installed under IE6. Opera 9.1 uses live blacklists from PhishTank and GeoTrust, as well as live whitelists from GeoTrust. Some implementations of this approach send the visited URLs to a central service to be checked, which has raised concerns about compromising the user's privacy. According to a report by Mozilla in late 2006, Firefox 2 was found to be more effective than Internet Explorer 7 at detecting fraudulent sites in a study by an independent software testing company. An approach introduced in mid-2006 involves switching to using a special DNS service that filters out known phishing domains, which will work with any browser. This is similar in principle to using a hosts file to block web adverts. To mitigate the problem of phishing sites spoofing a victim site and embedding its images (such as logos) in a spoof site, several site owners have responded by altering the images to send a message to the visitor. If the images were not requested in the normal way by visiting the real page then a warning that the site is fraudulent can be substituted for the usual image, or the original image can be moved to a new filename and the original permanently replaced with a warning.
Augmenting password logins - Bank of America is one of several websites that ask users to select a personal image, and display this user-selected image with any forms that request a password. Users are instructed to only enter a password when they see the image they selected; if the correct image does not appear, they are expected to recognize that the site is not legitimate. However, a recent study suggests few users refrain from entering their password when images are absent. This feature (like other forms of two-factor user authentication) is also susceptible to other attacks, such as those suffered by Scandinavian bank Nordea in late 2005, and Citibank in 2006. Security skins are a related technique that involves overlaying a user-selected image across the login form as a visual cue that the form is legitimate. However, unlike the website-based image schemes, this image is shared between the user and the browser, not between the user and the website. The scheme also relies on a mutual authentication protocol, which makes it less vulnerable to attacks that user-only authentication schemes are vulnerable to.
Eliminating phishing mail - Spam filters can also help by reducing the number of phishing emails that users receive.
Monitoring and takedown - 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. Individuals can contribute by reporting phishing to both volunteer and industry groups, such as PhishTank.