Requires a scriptlet to add cookies

[dimisa-RUAdList]

Sometimes cookies need to be added to prevent unwanted advertising behavior.

Example. On rustorka.com after registration and authorization, the first page refresh leads to a redirect if there is no "opt_js" cookie. After the redirect, this cookie is installed by the site and lives for 12 hours, after which the redirect is repeated.

The need to force the installation of cookies is quite common. In AdGuard base filter, the rules setting cookies #%#document.cookie are used 53 times, in AdGuard Russian filter - 10 times.

[gorhill]

I consider the open-ended ability to create new information which wasn't there before to be a security risk, not unlike the rewrite filter option as described at https://armin.dev/blog/2019/04/adblock-plus-code-injection/.

[dimisa-RUAdList]

AdGuard has been using #%#document.cookie for quite some time and so far no security issues have arisen.

Security risk
But, only filter authors can edit rules. Yes?

[mtxadmin]

Some malware sites prompt users to install their "lists", which, in fact, add exclusions for them. So, security concerns still exist. But I am agree with Dimisa, this functional will be useful sometimes.

[peace2000]

Another example, EU GDPR stuff related:

This site: https://www.tennisassa.fi/ sets a "you are required to accept cookie" wall that prevents an access to the site unless cookies are accepted. This could be bypassed by using a rule that adds a specific cookie there where cookies are set to accepted.

[mapx-]

Circumventing a paywall is considered out of scope. GDPR messages will not be addressed in uAssets.

[peace2000]

Circumventing a paywall is considered out of scope. GDPR messages will not be addressed in uAssets.

Hi, yeah I know that uAssets won't handle GDPR stuff, I used that site just as an example for this feature request what could be done if this feature was added.

[gorhill]

I prefer to decline, for the stated reason.

[Yuki2718]

uBlockOrigin/uAssets#17022
There was similar case(s) set-cookie could be very useful to block popup/under I don't remember now.