browser security

The term browser security can have various meanings.

This page was created to provide a quick reference to browser security. It also contains information regarding the data that may be sent by your browser when visiting other sites. Each individual is ultimately responsible for their own security. This information on this page is provided as a guide only. Following the links in this page will take you to more detailed articles on the specified topics.

What information does your browser send?

When your browser sends a request for a page to a web server, this request includes a HTTP header containing information about you and your request. Typically this includes your IP number and a string called "HTTP_REFERER"[sic]. These values are stored in server logs and may be retrieved by the server admin. You can increase your anonymity by using a proxy and blocking the referrer string sent by your browser. Following is a brief explanation of each of these pieces of information.

IP Number

While you are connected to the net, you are identified by a unique number know as an IP (Internet Protocol) number, or IP address. This takes the form n.n.n.n (ie. 127.1.67.235). If you are using a dial-up account it may be difficult to pinpoint you from this as the number will be shared among many users of your service provider. Your IP number will be dynamic. However, if you have a broadband account such as Cable, DSL, or are surfing from an institution such as a school or company, you may have a permanent, or static, IP number. If that is the case your number points directly to your computer.

If you are concerned that your activities may be linked back to you, you can use an anonymous proxy. The proxy server will handle http requests and your IP number will be replaced by the IP number of the proxy server in http headers. The links listed under a URL are free web-based proxy servers which will take you anonymously to the listed site. For a more permanent solution you can enter one of many free public anonymous proxies into your browser preferences to use with all your surfing. Lists of publicly-available anonymous proxies can be found at the following sites:

• http://www.atomintersoft.com/products/alive-proxy/proxy-list/
• http://www.antiproxy.com/proxysearch.php
• http://www.findproxy.com/

HTTP Referrer

When you click on a link embedded within a web page, your browser attempts to send the location of that page as a string known as "referrer". The address of this referring page is then stored in the logs of the server you are visiting. If you are clicking on a link from any site, the site address will be recorded along with your IP number.

The simplest way to circumvent the referrer problem when following links from non-FS sites is to open a new browser window, then copy and paste the URL (link address) into the address bar of this new window rather than clicking directly on the link. A few browsers will allow you to block the sending of the referrer in the preferences or browser settings. Doing this will enable you to click on links without fear of transmitting the location of the referring page.

What information does your browser store?

Your web browser stores a great deal of information every time you visit a web page. This information is often stored to make it easier to later find and reload already visited web pages. What information is stored, how and where, depends on which browser you use, which version you have, on what platform or operating system you are running it, and your personal security settings. Some of the items a browser may record are:

1. The address in your address bar drop-down list
2. Links to the page in your history
3. The page itself in your cache
4. Any embedded elements, such as graphics or scripts, separately in your cache
5. Cookies

Address Bar and History

Both the history and address-bar list make it easier to access recently-visited sites by storing the addresses of any site you visit. These effectively leave a breadcrumb trail for others to find and follow your activity on the internet. Anyone else who uses or has access to your browser can easily look at your recent internet activity. Many browsers allow you to change your settings to not store this information.

The Browser Cache

The cache is designed to make loading frequently-accessed pages quicker. Downloading a page from the internet takes time so the cache is designed to store entire pages from sites which you visit. Some browsers create a single cache file, while others may store embedded elements such as images, stylesheets or scripts separately. When you type an address into your browser it will check with the server to see if the page has been modified since last accessed and if there are no changes it will draw the page from the cache rather than from the server. The browser cache is a record of the sites you have visited and can easily be accessed by others.

Changing your browser settings to not keep a cache or history is advisable, but you still may wish to clear out these items periodically anyway.

Cookies

Cookies are small information packages that web sites use to identify you later. They are sent to your computer and stored when you visit certain sites, often without you being aware. Cookies are usually always used for innocent purposes such as automating log-in procedures and storing preferences, but they too leave their footprints for others to follow. Most browsers allow you to disable the automatic acceptance of cookies, either by denying all cookies, or asking you each time whether you would like to accept them or not.