Short bio

PUP.Optional.BrowseFox is Malwarebytes’ detection name for a large family of adware that uses different methods of browser hijacking and monetizing to get their message across.

Type and source of infection

BrowseFox adware is usually installed by a bundler, but they do create sites and offer them as separate downloads. The bundled installer is usually different from the official one. The bundled installers require arguments for a full installation and are sometimes even aware of running on a virtual machine, both to hinder researchers.


Malwarebytes protects users from PUP.Optional.BrowseFox by using real-time protection.

block PUP.Optional.BrowseFox

Malwarebytes blocks PUP.Optional.BrowseFox


Malwarebytes can detect and remove PUP.Optional.BrowseFox 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.

Malwarebytes removal log

A Malwarebytes log of removal will look similar to this:

Malwarebytes Anti-Malware

Scan Date: 5/13/2016
Scan Time: 9:10 AM
Logfile: mbamSearchExpanse.txt
Administrator: Yes

Malware Database: v2016.05.13.02
Rootkit Database: v2016.05.06.01
License: Premium
Malware Protection: Disabled
Malicious Website Protection: Enabled
Self-protection: Enabled

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

Scan Type: Threat Scan
Result: Completed
Objects Scanned: 310877
Time Elapsed: 8 min, 8 sec

Memory: Enabled
Startup: Enabled
Filesystem: Enabled
Archives: Enabled
Rootkits: Enabled
Heuristics: Enabled
PUP: Enabled
PUM: Enabled

Processes: 0
(No malicious items detected)

Modules: 0
(No malicious items detected)

Registry Keys: 6
PUP.Optional.Yontoo, HKLM\SOFTWARE\WOW6432NODE\CLASSES\CLSID\{99415057-7C50-439D-AA20-02D83C071B61}, Quarantined, [91d58154adec1026ab21fb4e9a68ac54], 
PUP.Optional.Yontoo, HKLM\SOFTWARE\CLASSES\WOW6432NODE\CLSID\{99415057-7C50-439D-AA20-02D83C071B61}, Quarantined, [91d58154adec1026ab21fb4e9a68ac54], 
PUP.Optional.Yontoo, HKLM\SOFTWARE\WOW6432NODE\CLASSES\CLSID\{F83D1872-D9FF-47F8-B5A0-49CC51E24EE8}, Quarantined, [a0c6884d8c0d9a9cb815a3a646bc4db3], 
PUP.Optional.Yontoo, HKLM\SOFTWARE\CLASSES\WOW6432NODE\CLSID\{F83D1872-D9FF-47F8-B5A0-49CC51E24EE8}, Quarantined, [a0c6884d8c0d9a9cb815a3a646bc4db3], 
PUP.Optional.BrowseFox, HKLM\SOFTWARE\WOW6432NODE\MICROSOFT\WINDOWS\CURRENTVERSION\UNINSTALL\Search Expanse, Quarantined, [6cfa72636a2fc2749854903b59a8e818], 
PUP.Optional.Yontoo, HKLM\SOFTWARE\WOW6432NODE\SearchExpanse, Quarantined, [26402ca9b5e4310585ab557e33d02ed2], 

Registry Values: 0
(No malicious items detected)

Registry Data: 0
(No malicious items detected)

Folders: 2
PUP.Optional.Yontoo, C:\Program Files (x86)\Search Expanse, Quarantined, [8ed832a39efb49edfdf99c049072956b], 
PUP.Optional.Yontoo, C:\Program Files (x86)\Search Expanse\Extensions, Quarantined, [8ed832a39efb49edfdf99c049072956b], 

Files: 4
PUP.Optional.BrowseFox, C:\Users\{username}\Desktop\SearchExpance.exe, Quarantined, [f86e24b19108d85efeee9d2e08f9a65a], 
PUP.Optional.BrowseFox, C:\Program Files (x86)\Search Expanse\Uninstaller.exe, Quarantined, [6cfa72636a2fc2749854903b59a8e818], 
PUP.Optional.Yontoo, C:\Program Files (x86)\Search Expanse\7za.exe, Quarantined, [8ed832a39efb49edfdf99c049072956b], 
PUP.Optional.Yontoo, C:\Program Files (x86)\Search Expanse\Extensions\firefox@www.searchexpanse.com.xpi, Quarantined, [8ed832a39efb49edfdf99c049072956b], 

Physical Sectors: 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.

  • 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.

If you want to allow the program to connect to the Internet, for example to fetch updates, also add an exclusion of the type Allow an application to connect to the internet and use the Browse button to select the file you wish to grant access.


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