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What You Should Know About History Sniffing

History Sniffing is a term used for Web sites that run simple Javascript tricks to snoop into visitors’ Web browsing history. These tricks are nothing new, but they are in the news again, so it’s a good time to remind you about ways to combat this sneaky behavior.

The recent news is based on a study released by University of California, San Diego researchers who found that a number of sites were “sniffing” the browsing history of visitors to record where they’d been.

This reconnaissance works because browsers display links to sites you’ve visited differently than ones you haven’t: By default, visited links are purple and unvisited links are blue. History-sniffing code running on a Web page simply checks to see if your browser displays links to specific URLs as purple or blue.

These are not new discoveries, but the fact that sites are using this technique to gather information from visitors seems to have caught many by surprise.

As has been broadly reported for months, Web analytics companies are starting to market products that directly take advantage of this hack. Eric Peterson reported on an Israeli firm named Beencounter that openly sells a tool to Web site developers to query whether site visitors had previously visited up to 50 specific URLs.

Fortunately, the browser makers (most of them) have responded. These sniffing attacks do not appear to work against the latest versions of Chrome and Safari. Within Mozilla Firefox, these script attacks can be blocked quite easily using a script-blocking browser plugin, such as the Noscript add-on.

Mozilla addressed this history-sniffing weakness in a bug report that persisted for eight years and was only recently corrected, but the changes won’t be rolled into Firefox until version 4 is released. As a result, current Firefox users still need to rely on script blocking to stop this.

Internet Explorer currently does not have a simple way to block scripts from within the browser (yes, users can block Javascript across the board and add sites to a whitelist, but that whitelist lives several clicks inside of the IE options panel).

So the safest browsers to guard you against History sniffing would be Chrome and Safari.

adapted via krebsonsecurity.com

  • 12/08/2010
  • IT

How cookies work in your browser.

Cookies may sound like they have something to do with delicious baked goods, but in terms of the Internet, they are simply small text files that allow a website to store information related to the user of the computer. These files are contained on the user’s computer, usually in the web browser’s folder.

The web browser itself will look for cookies in the computer folder specified for storing cookies. The browser will then open the file that is requested from a certain website, if one exists. If no cookie file exists, a new one will be created.

In addition, browsers regularly maintain cookies. Cookies also specify expiration dates. When these dates are reached, the browser will automatically delete the file from the computer.

Websites can also use cookies for statistical information, like tracking how many users visit the site, how many return, and which pages they visit. This is possible because websites can assign user IDs to computers, which are tracked using cookies. A counter in the cookie file can be set to increase every time the website is accessed by a computer with the same ID.

Cookies provide an easy way to customize and maintain the look of webpages to a user’s need, and it streamlines the services they provide. However, many people believe cookies may be a threat to personal security. While it is true that cookies collect a user’s information, they are not programs that can be run on the computer. Therefore, they are not viruses or any malicious programs that can read or erase information from a hard drive, and they will not cause pop-ups.

There are still drawbacks. Cookies can be intercepted as they are being relayed from website to computer. Recently a cookie exploitation called Firesheep, and allowed people to log on other users’ Facebook and Twitter accounts.

While people still debate whether the benefits of cookies outweigh the threats that they may pose, in the long run, cookies make the Internet more convenient and dynamic.

adapted via thetartan.org

  • 11/02/2010
  • IT

Fake Browser Warning Pages Distribute Malware

Security researchers warn that a new malware distribution campaign uses fake versions of the malicious site warnings commonly displayed by Firefox and Google Chrome.

Both Chrome and Firefox tap into Google’s Safe Browsing service in order to check if the accessed URLs are known attack sites.

If such malicious pages are detected, both browsers block them and display warning messages.

In such circumstances users are normally given the option to either leave the site or override the block and continue to load the page.

The pages look exactly the same as the real thing, except for a button that reads “Download Updates,” suggesting that security patches are available for the browsers.

The executable files served when these buttons are pressed install rogue antivirus programs, which try to scare users into paying a license fee.

Such attacks target vulnerabilities in outdated versions of popular software like Java, Flash Player, Adobe Reader or even the browsers themselves.

Successful exploitation results in malware being installed on the target computer in a way that is completely transparent to the victim.

Users are advised to keep their antivirus programs up to date and if possible to use script-blocking technologies available to their browsers, such as the NoScript extension for Firefox.

adapted via news.softpedia.com

  • 10/28/2010
  • IT