Anti-phishing measures have been implemented as features embedded in browsers, as extensions or toolbars for browsers, and as part of website login procedures. The following are some of the main approaches to the problem.
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, then 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 IE7 browser, Mozilla Firefox 2.0, and Opera all contain this type of anti-phishing measure. Firefox 2 uses Google anti-phishing software. 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 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 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 affect user-only authentication schemes.
Eliminating phishing mail
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
Source : wikipedia