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Infinite "Press OK" dialogs from bad advertisers are allowed to hijack Firefox. How do I stop them?

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Grand Master Contributor

Infinite "Press OK" dialogs from bad advertisers are allowed to hijack Firefox. How do I stop them?

Some "nasty" advertisers use a popup dialog that says "Press OK to Continue" or something along those lines. I know the OK button will take an action I do not want to allow, but the advertiser is exploiting something in Firefox to infinitely generate new dialogs whenever one is closed, until I press OK. During this, the Firefox browser will not allow me to close the offending tab or the offending browser window, so my only escape is Task Manager. After this happens I cannot restore my previous session because that session contains the hijacker.

I have included a URL that generated a popup that had this behavior, but it may or may not show up repeatedly, and it appears plenty of other places online as well.

Please take action so that an open dialog cannot prevent a tab or browser being closed.

WARNING: Following link in "URL of affected sites" may result in unpleasant browser behavior as described above.

URL of affected sites

http://letslikeit.com/page.php?ID=19#?=&cb=f1d5be6dcd2e93b&relation=parent&transport=fragment&frame=...

1 ACCEPTED SOLUTION

Accepted Solutions
Grand Master Contributor

Re: Infinite "Press OK" dialogs from bad advertisers are allowed to hijack Firefox. How do I stop them?

There is a bug filed to prevent infinite loop alerts, and until it's fixed you can install https://addons.mozilla.org/en-US/firefox/addon/13176 which solves this.

24 REPLIES
Support Forum Moderator

Re: Infinite "Press OK" dialogs from bad advertisers are allowed to hijack Firefox. How do I stop them?

If I try that link, I don't get any prompt. http://screencast.com/t/YTQ1MjdjZTIt

We'll need some more info about your Firefox setup. Go to Help > Troubleshooting Information, then click Copy all to Clipboard. Open a reply to this post, and go to Edit > Paste to paste the info from your Troubleshooting Information page.

Grand Master Contributor

Re: Infinite "Press OK" dialogs from bad advertisers are allowed to hijack Firefox. How do I stop them?

Troubleshooting information is already included above Smiley Happy I am able to click the [+] next to Troubleshooting Information and see it. Does it not appear for everyone?

Advertisers randomly rotate ads, so I am not sure how I can provide a link to a site that is guaranteed to show the behavior. The link I provided popped up several things, one of which was a pop-under with the nasty behavior.

To avoid a GIANT post I'll snip out the version, OS and plugins from troubleshooting info:

Firefox version

3.6.3

Operating system Windows 7

User Agent Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3

Plugins: All-in-One Gestures 0.21.1 Cooliris 1.11.6 DownThemAll! 1.1.10 Java Console 6.0.18 Flagfox 4.0.5 DownloadHelper 4.7.3 Tab Mix Plus 0.3.8.3 WOT 20100503


The core issue is Firefox prevents closing any tabs or windows when a dialog is open, and "bad" advertisers use this to force the user to click OK on a JS popup. If I find a site that ALWAYS launches an ad that does this I'll try to bring it back here.

Support Forum Moderator

Re: Infinite "Press OK" dialogs from bad advertisers are allowed to hijack Firefox. How do I stop them?

letslikeit.com is serving up advertisements from http://ads.lzjl.com/

You can "blacklist" that domain from being able to run JavaScripts in Firefox by using the YesScript addon. https://addons.mozilla.org/en-US/firefox/addon/4922/ The problem is that you will have to block every domain you come across that is doing ads that way.

Or you can install the Adblock Plus along with a Filterset subscription to block most advertisements. AdblockPlus https://addons.mozilla.org/firefox/1865/ Also, read this: http://adblockplus.org/en/getting_started

Grand Master Contributor

Re: Infinite "Press OK" dialogs from bad advertisers are allowed to hijack Firefox. How do I stop them?

I know a lot of people won't agree with me on this, but I don't like the idea of ad-blockers. I think it directly impacts a lot of my favorite little sites' ability to support themselves. (Comics, artists, bloggers, all of the little guys who give the net its best free content.) A lot of those guys are going to significant expense and effort to maintain those sites and often not making much from it. Also, the offending ads don't come from those sites. They're very good about responding to complaints and sending bad advertisers packing.

Blocking domain by domain won't work because they will always just start popping up from a new domain. I highly doubt "lzjl.com" is the first nor the last domain that company will register.


I appreciate the advice but those are band-aid solutions to what seems like a D.O.S. vulnerability in Firefox. If one nasty advertiser can render an entire browser session useless with a silly JS popup, and force MOST users into clicking their malicious OK button to make it stop, isn't that a problem with the browser? And if the only reason it works is because the user cannot interact with a browser window after it has generated a JS popup, isn't that kind of silly?

I'm posting this here because it's been this way for years and years and I'm amazed this lowbrow technique is still allowed to succeed.

Grand Master Contributor

Re: Infinite "Press OK" dialogs from bad advertisers are allowed to hijack Firefox. How do I stop them?

There is a bug filed to prevent infinite loop alerts, and until it's fixed you can install https://addons.mozilla.org/en-US/firefox/addon/13176 which solves this.

New Contributor

Re: Infinite "Press OK" dialogs from bad advertisers are allowed to hijack Firefox. How do I stop them?

I've found a website that foils both adblock as well as this "infinite loop" add-in. The page is at http://quiznexus.com/areyouasexgod1981/index.php?web_id=5284&exitpops=true.

When I try to close this page, it brings up a dialog that says "IMPORTANT: You are almost finished: You haven't completed the quiz!" It gives me the option of clicking "OK," but I'll bet anything that if I click on it, it will take me to their website. When I close that dialog, it brings up another one that says "Are you sure you want to navigate away from this page?" There are OK and Cancel buttons, but I'm sure those don't work as promised either. When I close that dialog, I'm back to square one.

Why can't Firefox give me a way to force a window closed regardless of the scripting? (E.g., let me hold down the Shift key while clicking the close box to disable scripts and just close.)

Another potential fix would be to let me configure Firefox so that it always displays the "whoops, this is embarrassing" dialog upon startup. That's the ONLY way I've found to kill these pages.

This diabolical website is just as effective at tying up Internet Explorer too.

I'm on Firefox 3.6.8 on Windows Vista that's up-to-date with patches.

Site Moderator

Re: Infinite "Press OK" dialogs from bad advertisers are allowed to hijack Firefox. How do I stop them?

Set the pref browser.sessionstore.max_resumed_crashes to 0 on the about:config page to get the about:sessionrestore page immediately with the first restart after a crash has occurred or the Task Manager was used to close Firefox.

See:

https://wiki.mozilla.org/Session_Restore#Preferences
http://kb.mozillazine.org/Browser.sessionstore.max_resumed_crashes

See also http://kb.mozillazine.org/Session_Restore#Firefox_keeps_crashing_after_restoring_a_session

New Contributor

Re: Infinite "Press OK" dialogs from bad advertisers are allowed to hijack Firefox. How do I stop them?

Every single app that I have seen that does this minimizes the browser window to prevent you from closing its tab. How about making it impossible for a web page to affect the size of the browser window?

As mentioned above, the page opened a "modal dialog" that made it impossible to switch back to any other tab or to click on any menu options of the browser. How about closing this gaping security hole?

New Contributor

Re: Infinite "Press OK" dialogs from bad advertisers are allowed to hijack Firefox. How do I stop them?

Best way that I have found to get around this annoying feature is as follows. From the menu select Tools / Options and then select the section Content and remove the check mark on Enable Java and finally click Ok. Since Java is now completely disabled you should be able to safely close the tab without the pesky message. Remember to replace the check mark on Enable Java to re-enable it. I have also opened a new browser window and dragged the offending tab to the new window and then closed that entire window session. Hope this provides some additional help!