RequestPolicy is a Firefox extension that improves the privacy and security of your browsing by giving you control over when cross-site requests are allowed by webpages you visit.
Cross-site requests are requests that your browser is told to make by a website you are visiting to a completely different website. Though usually legitimate requests, they often result in advertising companies and other websites knowing your browsing habits, including specific pages you view throughout the day. Among the attacks that cross-site requests are used in, they are particularly dangerous with Cross-Site Request Forgery (CSRF) attacks where your browser is told to make a request to another website and that other website thinks you (the person) meant to make the request.
With RequestPolicy, the default for any cross-site request is to deny it. Users are notified when requests on the current page have been blocked (the status bar flag icon at the bottom right of your browser turns red). Clicking on this status bar flag icon gives you a menu where you can view and modify which requests are blocked and allowed. You can whitelist requests you approve of by origin site, destination site, or specific origin-to-destination.

What's New in This Release:

Bug fixes:
· Whitelist bypass through view-source URLs.
· Refresh string parsing fails on Firefox 5+.
· "Get Addons" page has begun loading resources from a new destination which was being blocked.

Extension conflicts:
· Update extension compatibility rules for Norton Toolbars.

What's New in 0.5.21:

Extension conflicts resolved:
· Firefox Sync account setup captcha blocked.

Bugs fixed:
· On Firefox 3.6, we performed our profile-after-change work twice.

Other changes:
· On Firefox 4, add a toolbar button to the addon bar rather than using a status bar icon.
· Removed the option to use the alternative status bar icon (an image that said "RequestPolicy" instead of the flag icon).

What's New in 0.5.20:

Bugs fixed:
· Users should not be able to allow redirects to javascript URIs.
· Preferences window not tall enough on Mac.
· xml+xsl pages broken.
· Blocked content notification (the flag) stuck on one color after closing print preview window with window's "X" button.

Enhancements:
· Updated locales.
· Allow removing status bar/addon bar icon.

Misc:
· Various xul element IDs made more specific to avoid namespace clutter.
· Typeless request log iframe given type="chrome" (though AMO still shows warning "Typeless iframes/browsers must be local").

What's New in 0.5.19:

Bug fixes:
· Cross-site redirects from favicon requests bypass whitelist.
· Redirection to protocol-relative URLs can bypass the whitelist. (Thanks, Mike Cardwell, for discovering and reporting this.)
· Some missing image indicators have very small width.
· Missing image indicators unreliable on Firefox 4.
· Some context menu sections and status icon respond to right clicks, showing another menu.
· Non-integer meta refresh delay considered invalid.
· Occasional error removing history listener when closing window.
· "File Not Found" about:neterror page shown when blocked redirect has "Content-Disposition: attachment;".

Enhancements:
· Remember position on page reload.
· Show redirect notification for any blocked top-level document requests (e.g. javascript sets document.location).
· Show alt text on mouseover of missing image indicator (alt text added to title attribute).

Extension conflicts:
· Observation of https-everywhere URL rewrites incorrectly handled URLs with fragments.
· Requests from Update Scanner blocked and can't be whitelisted through the RequestPolicy menu.
· Local validation requests by Web Developer extension blocked

What's New in 0.5.18:
Bug fixes:
· Option to "disable dns prefetch on startup" didn't work reliably.
Enhancements:
· Updated locales.

What's New in 0.5.16:
Bug fixes:
· Updates or fresh installs of RequestPolicy on Firefox 4.0b7 would cause RequestPolicy to break due to installed extension XPIs not being extracted anymore.
· The openDialog wrapper had a latent bug triggered on Firefox 4.0b7 that (at a minimum) caused certain dialog windows from the addons manager to not open.
Extension conflicts resolved:
· RequestPolicy would block some requests where HTTPS Everywhere had changed the destination URL. Thanks to Peter, Mike, and Seth of HTTPS Everywhere for talking about, following up on, and applying the HTTPS Everywhere patch that corresponds to these RequestPolicy changes. That patch is applied in HTTPS Everywhere version 0.2.3.development.2.

What's New in 0.5.15:
Enhancements:
· Lots of fixes to support Firefox 4 beta (currently supported: 4.0b5pre).
· Request Log context menu added which allows copying and opening URLs from the log.
Bugs fixed:
· docShell.allowMetaRedirects not respected for same-site meta refreshes