Why do cookie "last used" times get updated for sites not recently visited?
Hi. I'm curious why the "last used" time of some cookies seems to get updated in FFQ 65.0.1 (on linux) even though the website has not been visited for a while. It doesn't happen for all sites, but it seems that many stored cookies get their last used time updated when FF is first opened. For example, under Prefs->Privacy&Security->"Manage Cookies and Site Data" the 3 cookies stored for qantas.com are marked as last used 2 hours ago (when I opened the browser) but I haven't visited the site for several days, don't have any open tabs for qantas, etc.
I'm speculating this might be because: 1. Cookies with short expiration times are being somehow refreshed? 2. Something to do with keeping history (but note qantas.com is not listed under Recently Closed Tabs or Windows or today or yesterday under History) 3. Something to do with the New Tab Tools addon (but no qantas sites appear anywhere on the newtab page)
Current P&S settings are to block trackers and cookies from unvisited websites, and not delete on close. If anyone understands what behaviour is causing the "last used" time to be updated, I'd welcome an explanation of what's going on.
Additional System Details
- User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:65.0) Gecko/20100101 Firefox/65.0
Many web pages 'talk' to other websites. One example is ads.
Unless those are 'bad' websites, I would not worry. If you want, you could disable 3rd party cookies, but that might cause some issues.
Thanks, but ads are completely blocked. The few open tabs are unlikely to be talking to qantas.com, but I'll do some experiments to eliminate that possibility. And it's not a case of worrying so much as figuring out what's happening here so I can choose my privacy/security settings and exceptions appropriately.
It may even be that FF is updating the last used time even though the cookie is not really being used. I don't really want to go to the trouble of analysing my web traffic, so I was hoping someone who understands how FF actually works with cookies could shed some light on this.
I think "last used" would require either sending the cookie to the site with a request, or receiving a set-cookie instruction from the site with a response. My suspicion would be that an image is getting retrieved for some reason, possibly related to the Firefox Home/New Tab page. In the old design, 15 tiles were prepared even if the current zoom level only resulted in a display of 8 tiles. In the current design of small tiles, I don't know whether there might be requests related to undisplayed sites.
It might be worth testing in Firefox's Safe Mode. When starting up in its Safe Mode, Firefox temporarily deactivates extensions, hardware acceleration, any userChrome.css/userContent.css files, and some other advanced features to help you assess whether these are causing the problem.
If Firefox is not running: Hold down the Shift key when starting Firefox. (On Mac, hold down the option/alt key instead of the Shift key.)
If Firefox is running: You can restart Firefox in Safe Mode using either:
- "3-bar" menu button > "?" Help button > Restart with Add-ons Disabled
- (menu bar) Help menu > Restart with Add-ons Disabled
and OK the restart.
Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).
The about:networking page should also show whether there has been a connection to this website (domain).
Thanks for the quick feedback jscher and cor-el.
Closing almost all tabs and restarting in safemode results in many cookies, including qantas.com, having their "last used" time immediately updated, however others still show 2 hours ago or 6 days ago. Interestingly, service.somedomain.com was updated while the related www.somedomain.com kept its older time. This suggests the "cookies" are actually different types that are being treated differently on startup. (Both somedomain sites appear in SiteSecurityServiceState.txt in the profile with similar values and qantas.com does not appear there.)
After restarting again in regular mode with minimal tabs about:networking shows 2 inactive http connections, and 1 active https connection:
I was on the phone company website before logging out, closing the tab, restarting in safemode, restarting again, so if about:networking is to be believed the connection has persisted despite all that. Perhaps something to do with FF being able to restore a closed tab? I'll try turning on logging to see what happens onthe next startup.