Does this occur every time that you type "pon" into the address bar?

For some reason your browser treated "pon" as a website address and opened it.

I tried to go to http://pon/ like the site in your screenshot, but it brought me to another website.

Sometimes a problem with Firefox may be a result of malware installed on your computer, that you may not be aware of.

You can try these free programs to scan for malware, which work with your existing antivirus software:

• Microsoft Safety Scanner
• MalwareBytes' Anti-Malware
• TDSSKiller - AntiRootkit Utility
• Hitman Pro
• ESET Online Scanner

Microsoft Security Essentials is a good permanent antivirus for Windows 7/Vista/XP if you don't already have one.

Further information can be found in the Troubleshoot Firefox issues caused by malware article.

Please report back soon.

NOTE: You should always upload a screenshot using the support forum by following these steps. Users don't always open links on the support forum because they pose a security issue.

I tried typing "pon" in again, 5-6 times. Same tab, new tab, new window, quit firefox and restarted. The same webpage from my screenshot came up every time.

I tried doing it in Safari (got www.pon.net) and Chrome (got a Google search for "pon") with different results.

I did consider malware, but those links you posted are for Windows. (BTW, I agree with your recommendation of MSE and run it on my PC.) Is there a Mac scanner or a FF add-on that could check for this sort of thing?

Shoot!
I forgot that you are a Mac user!
Sorry about that!

Here is one that I found online. It is free, but I have never used it because I am a Windows user.

WARNING: Always use caution when downloading content from the internet. I will take no responsibility for any damage caused by a download. Download at your own risk!

Based on some online reviews, I'm going to try ClamXav and the free trial of MacScan instead. It may take a while to run the scans, but I'll post whether or not the same webpage still appears after they're done.

When I typed in "pon" in the address bar, it brought me to the Google search results.

When I typed in "http://pon/" like in the screenshot, it brought me to www.pon.com.

I think it is a malware issue.

Ran ClamXav. It flagged an .ipa file in my iTunes folder. I no longer use the app, so I deleted it.

Ran MacScan. It found and deleted 122 tracking cookies. I also used it to delete history, cache, and temp files.

Typing "pon" in the address bar still returns that same webpage. I don't have time right now, but at some point I'm going to start disabling my add-ons, one by one, and see if it makes a difference.

Maybe it's a problem with your DNS (domain name server). Try to connect with to that website after changing to another DNS server. Personally, I recommend OpenDNS (http://www.opendns.com/). Report back after trying it.

Before you use trial and error to find the add-on causing the issue, it is important to find out if it is an add-on causing the issue. This can be done by running Firefox is Safe Mode.

Safe Mode is a troubleshooting mode, which disables most add-ons.

(If you're not using it, switch to the Default theme.)

• You can open Firefox 4.0+ in Safe Mode by holding the Shift key when you open the Firefox desktop or Start menu shortcut.
• Or open the Help menu and click on the Restart with Add-ons Disabled... menu item while Firefox is running.

Once you get the pop-up, just select "'Start in Safe Mode"

If the issue is not present in Firefox Safe Mode, your problem is probably caused by an extension, and you need to figure out which one. Please follow the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article for that.

To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before opening Firefox for normal use again.

Please report back with your Safe Mode results soon.

Firefox would normally try to fix up the url and add .com suffix. As this isn't happening for you something else is wrong.

• https://support.mozilla.org/kb/Location+bar+search

Create a new profile as a test to check if your current profile is causing the problems.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer some files from an existing profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over the problem.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

It may be interesting to note

• As of Firefox 23 all searches within Firefox, including the addressbar now match the setting from the current search bar. That can lead to unexpected results, and is inconvenient if you are used to setting the searchbar differently from the address bar,
  but it allow a user to quickly change the addressbar search without needing to go into more advanced settings
  • See Search bar - add, change and manage search engines on Firefox
  • This handy extensionSearch Reset resets search related preferences and then uninstalls itself https://addons.mozilla.org/en-US/firefox/addon/searchreset/

• Malware KB article
  • this link should redirect for you to a Mac version Troubleshoot Firefox issues caused by malware article
    Direct link to Mac version /kb/troubleshoot-firefox-issues-caused-m... Note the malware advice links within that article will be suitable for a Mac user.

Did you try Firefox's safe mode by the way ? and did your issue then go away or not ?

I appreciate everyone's input. I'm at work right now, so I'm not able to devote my full attention to this, but I've tried two quick things:

Booted FF into Safe Mode: problem still happening.

Changed DNS servers to Google DNS (I have them memorized, I can try OpenDNS later): problem still happening.

I'll try the profile suggestion and read the malware KB link later today.

I reset Firefox to its default state. Verified all extensions and my custom theme were gone. Problem still happening.

After doing the Reset, I typed a couple dozen random (e.g. ZJW) and not-so-random (e.g. PWN, of which PON is supposed to be an alternate spelling) three letter strings into the address bar. Every single one resulted in a Google search for the string.

I created a brand new user account on my Mac and opened FF inside the user account. Problem still happening. User folders are completely separate on the Mac, and the FF application support folder for the new account is completely new, so if it's malware, it has to be in a location accessible by both accounts?

I'm ready to copy the FF application package contents to another Mac and let Spotlight search the contents of every file.

Comments rather than a solution.

I am not sure how a Mac works, or the Filepaths used for Firefox program and profile folders | directories.

If you do a new install of Firefox it will attempt to use any pre existing profile.
Standard Installs

• on Windows will be global, but with a separate Firefox Profile for each user account.
• Linux would be similar, although I do have a Linux system with a Global Firefox install plus multiple versions and multiple profiles for single user accounts that have the profile and program paths within a user account.

Firefox Reset
Operates on the default profile, not on other profiles if the account has multiple profiles. Which profile is reset will depend on

• Which user account is used to perform the reset.
• Which profile was used last, because that is designated as the default account. (Not necessarily the account named default)

You said

After doing the Reset, I typed a couple dozen random (e.g. ZJW) and not-so-random (e.g. PWN, of which PON is supposed to be an alternate spelling) three letter strings into the address bar. Every single one resulted in a Google search for the string 

• Do you agree that is the expected and correct default behaviour of Firefox?

Just a thought. You did not provide full troubleshooting information when you asked the question.

• I am wondering do you have a file user.js ?

The file does not exist by default it is optional, but you, or software, may have created the file. (More than one if multiple profiles).

• see http://kb.mozillazine.org/User.js_file

Note safe mode does not have an effect on custom preferences.

• Did you try cor-el's suggestion of creating a new profile ?
  • That is a more advanced option than using Firefox Reset, but does give you more control. It also makes comparisons and changes easier to do.
  • It is a short step from there; if necessary; to run multiple instances of Firefox simultaneously with separate & differently configured profiles.

Another thought.
Do you realise that Firefox 23 uses the search engine as set in the SearchBar for all searches including the addressbar. So if you are changing the searchbar search you will change the address bar's search.

Does MacOS X have anything like the Windows hosts file, statically associating host names with IP addresses, and bypassing a normal DNS search? While it seems unlikely that pon would be in there, everything about the problem seems quite unlikely. ;-)