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Short bio

PUP.Optional.DefaultSearch is Malwarebytes’ detection name for a family of browser hijackers targeting Chrome, Firefox and Internet Explorer.


The browsers’ default search engine was changed  to one that belonged to the threat-actors.


block 1-1ads.com

Malwarebytes blocks 1-1ads.com


Malwarebytes can detect and remove PUP.Optional.DefaultSearch without further user interaction.

  1. Please download Malwarebytes to your desktop.
  2. Double-click MBSetup.exe and follow the prompts to install the program.
  3. When your Malwarebytes for Windows installation completes, the program opens to the Welcome to Malwarebytes screen.
  4. Click on the Get started button.
  5. Click Scan to start a Threat Scan.
  6. Click Quarantine to remove the found threats.
  7. Reboot the system if prompted to complete the removal process.

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.

  • Open Malwarebytes for Windows.
  • Click the Detection History
  • Click the Allow List
  • To add an item to the Allow List, click Add.
  • Select the exclusion type Allow a file or folder and use the Select a folder button to select the main folder for the software that you wish to keep.
  • Repeat this for any secondary files or folder(s) that belong to the software.


Associated files: 

Chrome extension: iomphmdalfmaifjccmagmllnicjoghhk

Firefox extension: defsearchp@gmail.com.xpi