PUA_EFASTBROWSER.SM
Win32:Adware-CZK [Adw] (Avast)
Windows
Threat Type: Potentially Unwanted Application
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This potentially unwanted application arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
TECHNICAL DETAILS
Arrival Details
This potentially unwanted application arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
Installation
This potentially unwanted application adds the following folders:
- %Application Data%\eFast
(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
It drops the following files:
- %User Temp%\{random folder}\setup.exe
- %Application Data%\eFast\Application\efast.exe
(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
Autostart Technique
This potentially unwanted application drops the following shortcut pointing to its copy in the User Startup folder to enable its automatic execution at every system startup:
- C:\DOCUMENTS AND SETTINGS\{user}\Desktop\eFast.lnk
- %Application Data%\MICROSOFT\INTERNET EXPLORER\QUICK LAUNCH\eFast.lnk
- C:\DOCUMENTS AND SETTINGS\{user}\START MENU\Programs\eFast\eFast.lnk
(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
Other System Modifications
This potentially unwanted application adds the following registry keys:
HKEY_CURRENT_USER\Software\eFast
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Uninstall\
eFast
HKEY_CLASSES_ROOT\eFastHTM.EWOPTCA22WH7J6Q64EA73K5EWM
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
MediaPlayer\ShimInclusionList\efast.exe
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\App Paths\
efast.exe
HKEY_LOCAL_MACHINE\SOFTWARE\Clients\
StartMenuInternet\eFast.EWOPTCA22WH7J6Q64EA73K5EWM
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\RegisteredApplications
"eFast.EWOPTCA22WH7J6Q64EA73K5EWM" = "Software\Clients\StartMenuInternet\eFast.EWOPTCA22WH7J6Q64EA73K5EWM\Capabilities"
HKEY_LOCAL_MACHINE\SOFTWARE\Clients\
StartMenuInternet\eFast.EWOPTCA22WH7J6Q64EA73K5EWM\Capabilities
"ApplicationDescription" = "eFast is a web browser that runs webpages and applications with lightning speed. It's fast, stable, and easy to use. Browse the web more safely with malware and phishing protection built into eFast."
It creates the following registry entry(ies) to bypass Windows Firewall:
HKEY_LOCAL_MACHINE\SYSTEM\{Current control set}\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List\%Application Data%\eFast\
Application
"efast.exe" = "{default}"
Other Details
This potentially unwanted application connects to the following possibly malicious URL:
- redirector.{BLOCKED}1.com
SOLUTION
Step 1
Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.
Step 2
Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.
Step 3
Search and delete this file
- %User Temp%\{random folder}\setup.exe
- %Application Data%\eFast\Application\efast.exe
- C:\DOCUMENTS AND SETTINGS\{user}\Desktop\eFast.lnk
- %Application Data%\MICROSOFT\INTERNET EXPLORER\QUICK LAUNCH\eFast.lnk
- C:\DOCUMENTS AND SETTINGS\{user}\START MENU\Programs\eFast\eFast.lnk
Step 4
Search and delete this folder
- %Application Data%\eFast
Step 5
Delete this registry key
Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.
- In HKEY_CURRENT_USER\Software
- "eFast" = ""
- "eFast" = ""
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Uninstall
- "eFast" = ""
- "eFast" = ""
- In HKEY_CLASSES_ROOT
- "eFastHTM.EWOPTCA22WH7J6Q64EA73K5EWM" = ""
- "eFastHTM.EWOPTCA22WH7J6Q64EA73K5EWM" = ""
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MediaPlayer\ShimInclusionList
- "efast.exe" = ""
- "efast.exe" = ""
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths
- "efast.exe" = ""
- "efast.exe" = ""
- In HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet
- "eFast.EWOPTCA22WH7J6Q64EA73K5EWM" = ""
- "eFast.EWOPTCA22WH7J6Q64EA73K5EWM" = ""
Step 6
Delete this registry value
Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.
- In HKEY_LOCAL_MACHINE\SYSTEM\{Current control set}\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List\%Application Data%\eFast\Application
- "efast.exe" = "{default}"
- "efast.exe" = "{default}"
- In HKEY_LOCAL_MACHINE\SOFTWARE\RegisteredApplications
- "eFast.EWOPTCA22WH7J6Q64EA73K5EWM" = "Software\Clients\StartMenuInternet\eFast.EWOPTCA22WH7J6Q64EA73K5EWM\Capabilities"
- "eFast.EWOPTCA22WH7J6Q64EA73K5EWM" = "Software\Clients\StartMenuInternet\eFast.EWOPTCA22WH7J6Q64EA73K5EWM\Capabilities"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet\eFast.EWOPTCA22WH7J6Q64EA73K5EWM\Capabilities
- "ApplicationDescription" = "eFast is a web browser that runs webpages and applications with lightning speed. It's fast, stable, and easy to use. Browse the web more safely with malware and phishing protection built into eFast."
- "ApplicationDescription" = "eFast is a web browser that runs webpages and applications with lightning speed. It's fast, stable, and easy to use. Browse the web more safely with malware and phishing protection built into eFast."
Step 7
Scan your computer with your Trend Micro product to delete files detected as PUA_EFASTBROWSER.SM. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.
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