Short bio

PUP.Optional.ForcedInstalledExtensionFF is a generic detection for a large family of browser extensions that target Firefox.


PUP.Optional.ForcedInstalledExtensionFF downloads additional code from a location hardcoded in the extensions’ javascript. Using this method these extensions can behave as coin-miners, search hijackers, or any other type of extension.

Type and source of infection

PUP.Optional.ForcedInstalledExtensionFF are forced on the user by making it as difficult as possible to leave the site without installing the extension.


Malwarebytes protects against PUP.Optional.ForcedInstalledExtensionFF by blocking the sites that push these extensions using the web protection module.

block dictionaryext.xys

Malwarebytes blocks dictionaryext.xys


Malwarebytes can detect and remove PUP.Optional.ForcedInstalledExtensionFF 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. Once the program has fully updated, select Scan Now on the Dashboard. Or select the Threat Scan from the Scan menu.
  5. If another update of the definitions is available, it will be implemented before the rest of the scanning procedure.
  6. When the scan is complete, make sure that all Threats are selected, and click Remove Selected.
  7. Restart your computer when prompted to do so.

Malwarebytes log

An example of how a removal log for PUP.Optional.ForcedInstalledExtensionFF would look:


-Log Details-
Scan Date: 2/7/18
Scan Time: 9:04 AM
Log File: 94567eaa-0bdd-11e8-9439-080027750297.json
Administrator: Yes

-Software Information-
Components Version: 1.0.262
Update Package Version: 1.0.3887
License: Premium

-System Information-
OS: Windows 7 Service Pack 1
CPU: x64
File System: NTFS
User: {computername}\{username}

-Scan Summary-
Scan Type: Threat Scan
Result: Completed
Objects Scanned: 241624
Threats Detected: 1
Threats Quarantined: 1
Time Elapsed: 4 min, 40 sec

-Scan Options-
Memory: Enabled
Startup: Enabled
Filesystem: Enabled
Archives: Enabled
Rootkits: Disabled
Heuristics: Enabled
PUP: Detect
PUM: Detect

-Scan Details-
Process: 0
(No malicious items detected)

Module: 0
(No malicious items detected)

Registry Key: 0
(No malicious items detected)

Registry Value: 0
(No malicious items detected)

Registry Data: 0
(No malicious items detected)

Data Stream: 0
(No malicious items detected)

Folder: 0
(No malicious items detected)

File: 1
PUP.Optional.ForcedInstalledExtensionFF, C:\USERS\{username}\APPDATA\ROAMING\MOZILLA\FIREFOX\PROFILES\{profile}.default\{F4262989-6DE0-4604-918F-663B85FAD605}.XPI, Quarantined, [4633], [486396],1.0.3887

Physical Sector: 0
(No malicious items detected)


Add an exclusion

Should users wish to keep this program and exclude it from being detected in future scans, they can add the program to the exclusions list. Here’s how to do it.

The Exclusions tab includes a list of items to be excluded from scans. The items may include files, folders, websites, or applications that connect to the Internet, as well as previously detected exploits.

To access the exclusions in Malwarebytes:

  • Click on the Settings tab in the left pane.
  • Click on the Exclusions tab.
  • Click the Add Exclusion button.
  • Select the exclusion type Exclude a File or Folder and use the Browse button to select the main folder for the software that you wish to keep.

Select your language