RFE: Option to anonymize requests #415

I'm a longtime user of NoScript with its Application Boundary Enforcer module, and was actually thinking of writing a graphical frontend for ABE, but I've now discovered that uMatrix covers >90% of general usage...

One important remaining advantage of ABE is the ability to anonymize requests: strip cookies, Authorization header, and POST body. This is beneficial both for security - preventing attacks like CSRF - and privacy (since it strips cookies).

Is it feasible for uMatrix to perform this kind of anonymization?

NoScript is GPL-licensed, if its source would be helpful, and there is an unofficial Git repo at https://github.com/avian2/noscript

Cookie headers are stripped when the cookie cell associated with a specific destination is in block mode.

For POST requests, are there use cases for when we want the requests to reach the server but without the content?

Excellent point about cookies, I overlooked that column.

Stripping POST bodies is more of a security safeguard, I guess, rather than general content blocking. NoScript routinely does this whenever sites that are not on its whitelist send cross-site POST requests. It effectively disarms many CSRF/XSS attacks. Less important, of course, when you're fully controlling the matrix of cross-site requests with a default-deny.

Any chance of affecting Authorization headers? It might even make sense to strip them whenever cookies are stripped, as a special case (they're two different types of authentication headers, really).

On firefox, one could set the LOAD_ANONYMOUS flag on the channel. It removes cookies, authentication headers, referrers and Origin headers (for CORS requests).

That may break more sites than just blocked cookies though, so it probably has to be a separate option.

My analysis of this:
Cookies - already stripped when the cookie cell is blocked
Referer - rewritten/removed for third party requests via referrer-spoof
Origin - altering would break CORS and server-side CSFR checks
POST body - webRequest exposes body as read only, it can only be cancelled (LOAD_ANONYMOUS flag is gone since FF 57)
Authorization - worth doing for Basic/Digest, otherwise it could break APIs