Trojan.BrowserAssistant.PS

Short bio

Trojan.BrowserAssistant.PS is Malwarebytes’ detection name for a Trojan that injects javascript code in targeted browsers (Edge and Firefox). The BrowserAssistant installer is signed by Realistic Media Inc. and aimed at Windows systems.

Symptoms

Users of affected systems may see this entry in their list of installed Programs and Features:

and these items in the Windows Startup folder:

Type and source of infection

Trojan.BrowserAssistant.PS is a Trojan that allows the threat actor to show advertisements in the affected browsers.
Trojan.BrowserAssistant.PS is installed as part of bundlers.

Protection

Malwarebytes protects users from Trojan.BrowserAssistant.PS by using real-time protection.

Malwarebytes blocks Trojan.BrowserAssistant.PS

Home remediation

Malwarebytes can detect and remove Trojan.BrowserAssistant.PS without further user interaction.

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

Business remediation

How to remove Trojan.BrowserAssistant.PS with the Malwarebytes Nebula console

You can use the Malwarebytes Anti-Malware Nebula console to scan endpoints.

Nebula endpoint tasks menu

Choose the Scan + Quarantine option. Afterwards you can check the Detections page to see which threats were found.

On the Quarantine page you can see which threats were quarantined and restore them if necessary.

Malwarebytes removal log

A Malwarebytes log of removal will be huge but should contain these entries:

Malwarebytes
www.malwarebytes.com

-Log Details-
Scan Date: 7/25/19
Scan Time: 1:16 PM
Log File: a687e548-aecd-11e9-ad51-00ffdcc6fdfc.json

-Software Information-
Version: 3.7.1.2839
Components Version: 1.0.586
Update Package Version: 1.0.11712
License: Premium

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

-Scan Summary-
Scan Type: Threat Scan
Scan Initiated By: Manual
Result: Completed
Objects Scanned: 237392
Threats Detected: 2255
Threats Quarantined: 2255
Time Elapsed: 48 min, 59 sec

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

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

Module: 0
(No malicious items detected)

Registry Key: 1
Trojan.BrowserAssistant.Powershell, HKCU\SOFTWARE\REALISTIC MEDIA INC.\Browser Assistant, Quarantined, [3839], [661357],1.0.11712
Registry Value: 1
PUP.Optional.QXSearch, HKCU\SOFTWARE\GOOGLE\CHROME\PREFERENCEMACS\Default\extensions.settings|pidepfbnmnemhcencgnfhhfnfiebdgjk, Quarantined, [352], [676735],1.0.11712

Registry Data: 0
(No malicious items detected)

Data Stream: 0
(No malicious items detected)

Folder: 148
Trojan.BrowserAssistant.PS, C:\Users\{username}\AppData\Roaming\Browser Assistant\node_modules\@cliqz-oss\firefox-client\test, Quarantined, [3840], [710827],1.0.11712
Trojan.BrowserAssistant.PS, C:\Users\{username}\AppData\Roaming\Browser Assistant\extension\js, Quarantined, [3840], [710827],1.0.11712
Trojan.BrowserAssistant.PS, C:\Users\{username}\AppData\Roaming\Browser Assistant\node_modules, Quarantined, [3840], [710827],1.0.11712
Trojan.BrowserAssistant.PS, C:\Users\{username}\AppData\Roaming\Browser Assistant\WebDrivers, Quarantined, [3840], [710827],1.0.11712
Trojan.BrowserAssistant.PS, C:\Users\{username}\AppData\Roaming\Browser Assistant\extension, Quarantined, [3840], [710827],1.0.11712
Trojan.BrowserAssistant.PS, C:\Users\{username}\AppData\Roaming\Browser Assistant\edge\x86, Quarantined, [3840], [710827],1.0.11712
Trojan.BrowserAssistant.PS, C:\Users\{username}\AppData\Roaming\Browser Assistant\engine, Quarantined, [3840], [710827],1.0.11712
Trojan.BrowserAssistant.PS, C:\Users\{username}\AppData\Roaming\Browser Assistant\edge, Quarantined, [3840], [710827],1.0.11712
Trojan.BrowserAssistant.PS, C:\Users\{username}\AppData\Roaming\Browser Assistant\api, Quarantined, [3840], [710827],1.0.11712
Trojan.BrowserAssistant.PS, C:\USERS\{username}\APPDATA\ROAMING\BROWSER ASSISTANT, Quarantined, [3840], [710827],1.0.11712
Trojan.BrowserAssistant.Powershell, C:\USERS\{username}\APPDATA\ROAMING\MICROSOFT\WINDOWS\START MENU\PROGRAMS\STARTUP\UPDATER.LNK, Quarantined, [3839], [652810],1.0.11712

Physical Sector: 0
(No malicious items detected)

WMI: 0
(No malicious items detected)

(end)

Traces/IOCs

You may see these entries in FRST logs:

Startup: C:\Users\{username}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup\BrowserAssistant.lnk [2019-07-25]
ShortcutTarget: BrowserAssistant.lnk -> C:\Users\{username}\AppData\Roaming\Browser Assistant\BrowserAssistant.exe (Realistic Media Inc. -> )
Startup: C:\Users\{username}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup\updater.lnk [2019-07-25]
ShortcutAndArgument: updater.lnk -> C:\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell.exe => -noninteractive -ExecutionPolicy bypass -c “try{$w=”$env:APPDATA”+’\Browser Assistant\’;[Reflection.Assembly]::Load([System.IO.File]::ReadAllBytes($w+’Updater.dll’));$i=new-object u.U;$i.R()}catch{}”

C:\Users\{username}\AppData\Roaming\Browser Assistant

Browser Assistant (HKLM-x32\…\{367D5074-5E48-40AF-B009-7D3839DAE5E4}) (Version: 1.21.6922.27430 – Realistic Media Inc.)