Troubleshoot Firefox issues caused by malware

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  • Revision id: 17756
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  • Creator: scoobidiver
  • Comment: added TDSSKiller, reworded specialized forum intro
  • Reviewed: Yes
  • Reviewed:
  • Reviewed by: AliceWyman
  • Is approved? Yes
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Malware is short for "Malicious Software". It is a term generally used for software installed on your computer that is designed to infiltrate or damage a computer system without the owner's informed consent. Sometimes a problem with Firefox may be a result of malware installed on your computer, that you may not be aware of. This article describes what common symptoms are and how to prevent malware from being installed and get rid of them.

How do I know that my Firefox problem is a result of malware?

Symptoms are various and depend on the malware but if you have one or several of these behaviors, you may have malware installed on your computer.

How do I prevent malware from being installed?

There are simple rules to follow in order to prevent malware from being installed on your computer:

  • Keep your operating system and other software updated: Installation of malicious software usually takes advantage of known security vulnerabilities in other programs, which may have been patched in later versions. Make sure you are using the latest version of each piece of software you use, including plugins using Mozilla's plugincheck website and Windows using the Windows Update feature.
  • Don't install untrusted software: Some websites offer you software to accelerate your browser, to help you search the Web, to add toolbars that make things Firefox already does. Some unwanted programs also come bundled in software packages. Usually, these programs gather information on your browsing behavior that serve only people who designed them and interfere with Firefox. Make sure you install add-ons from Mozilla's add-on website and you uncheck unwanted programs in software wizards.
  • Don't click inside misleading pop-up windows: Many malicious websites try to install malware on your system by making images look like pop-up windows, or displaying an animation of the website scanning your computer. For more information on detecting a misleading pop-up, see Pop-up blocker settings, exceptions and troubleshooting.
  • Run anti-virus and anti-spyware real-time protection and scan your system periodically. Make sure your anti-virus and anti-spyware real-time protection is enabled. Scan your computer at least every month.
  • Don't run a fake Firefox: Download Firefox from mozilla.com.
    Note: Please report misuse of the Firefox trademark using the Mozilla Violating Website Report page

How do I get rid of malware?

If your anti-virus and anti-spyware software hasn't detected malware, scan your system with other free malware scanning programs. You need to scan with all programs because each program detects different malware and make sure that you update each program to get the latest version of their databases before doing a scan.

Warning: Anti-virus and anti-spyware software may sometimes generate false positives. Consider quarantining suspicious files rather than deleting them.

If Firefox opens multiple tabs or windows with unwanted content or crashes at startup, try also:

If the problem still continues, ask for help in specialized forums for malware removal such as those listed below: