Tue 05 Sep 2023 02:47:42 PM EEST

Minor firefox DoS - semi silently polluting ~/Downloads with files

This is barely a DoS, but since Chrome has explicit protection against it, we decided to disclose it.

If firefox user visits a specially crafted page, then firefox may create many files in ~/Downloads, The user is notified about this in a small dialog, but there is no option to stop the downloads. The potential denial of service is that the user must manually delete the created files and this might be PITA.

Technically about the PoC: create non-empty file xml.doc. To force download, add to the page iframe src="xml.doc". To force creation of new files, add body onload="location.reload()" (there are several other options about this).

Proof of concept

To out surprise, Chrome is safe from this and it distinguishes manual download from automated download and this might be because it is aware about this DoS.

Affected: firefox 117 on GNU/Linux and reportedly on Windows. Not Affected: firefox on android, Chrome, lynx.

Posted by joro | Permanent link