It is a adware/malware disguised as something good.

Please go to the firefox menu ≡ > addons > extensions & remove any suspicious entries (toolbars, things that you have not installed intentionally, don't know what purpose they serve, etc). Remove CouponXplorer Toolbar from Mac OS X system : If you are using OS X, click Go button at the top left of the screen and select Applications. Wait until you see Applications folder and look for CouponXplorer Toolbar or any other suspicious programs on it. Or go to the where add remove/programs on a Mac and remove all toolbars or potentially unwanted software from there. finally, run a full scan of your system with different security tools.

https://support.mozilla.org/en-US/kb/remove-toolbar-has-taken-over-your-firefox-search

https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware Run more than 1 as 1 does not catch it all. and inf need help follow guidelines, save your reports, google each before deleting. Post in 1 forum only.

Further things might be necessary.

Please let us know if this solved your issue or if need further assistance.

Thank you very much for the information. I was able to remove unwanted malware!

I am glad to hear that your problem has been resolved. If you haven't already, please select the answer that solves the problem. This will help other users with similar problems find the solution more easily. Thank you for contacting Mozilla Support.