Short bio

Trojan.FBSpammer is Malwarebytes’ detection name for a family of Firefox extensions that are designed to spam Facebook groups.


Users of affected systems may notice a Firefox extension that is called Page Update and the corresponding .xpi file has a random name consisting of capital characters and underscores.

Page Update extension

Users may also notice posts made on their behalf on Facebook groups they did not join themselves.

Type and source of infection

Trojan.FBSpammer is a Firefox extension that joins multiple Facebook groups and starts posting in them on behalf on the victim.
Trojan.FBSpammer is installed from websites that offer it as a Flash update.

fake Flash update


Both the Web protection module and the Malwarebytes browser extension block the websites pushing this malicious extension.

Malwarebytes browser extension


Malwarebytes can detect and remove Trojan.FBspammer without further user interaction.

  1. Please download Malwarebytes to your desktop.
  2. Double-click mb3-setup-consumer-{version}.exe and follow the prompts to install the program.
  3. Then click Finish.
  4. It is advisable but not required to close Firefox before you start the scan.
  5. Once the program has fully updated, select Scan Now on the Dashboard. Or select the Threat Scan from the Scan menu.
  6. If another update of the definitions is available, it will be implemented before the rest of the scanning procedure.
  7. When the scan is complete, make sure that all Threats are selected, and click Remove Selected.
  8. Restart your computer when prompted to do so.


Extension name examples:


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