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Adware.Win32.CToolBar.AA

March 21, 2020
 PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:
 SYSTEM IMPACT RATING:
 INFORMATION EXPOSURE:

  • Threat Type: Adware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This Adware 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

File Size:

1,152,000 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

21 Mar 2020

Arrival Details

This Adware 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 Adware creates the following folders:

  • %User Temp%\TBR5LanguageAct
  • %User Temp%\Languages

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Autostart Technique

This Adware registers itself as a BHO to ensure its automatic execution every time Internet Explorer is used by adding the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\explorer\
Browser Helper Objects\{1CB20BF0-BBAE-40A7-93F4-6435FF3D0411}

Other System Modifications

This Adware adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Wow6432Node\CLSID\{4D25FB7A-8902-4291-960E-9ADA051CFBBF}
(Default) = ""

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Wow6432Node\CLSID\{4D25FB7A-8902-4291-960E-9ADA051CFBBF}\
InprocServer32
(Default) = "%User Temp%\{malware file name}.dll"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Wow6432Node\CLSID\{4D25FB7A-8902-4291-960E-9ADA051CFBBF}\
InprocServer32
ThreadingModel = "Apartment"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
{malware file name}.R404Pro
(Default) = ""

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
{malware file name}.R404Pro\Clsid
(Default) = "{4D25FB7A-8902-4291-960E-9ADA051CFBBF}"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Wow6432Node\CLSID\{4D25FB7A-8902-4291-960E-9ADA051CFBBF}\
ProgID
(Default) = "{malware file name}.R404Pro"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
PROTOCOLS\Handler\tbr
(Default) = "tbr"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
PROTOCOLS\Handler\tbr
CLSID = "{4D25FB7A-8902-4291-960E-9ADA051CFBBF}"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Wow6432Node\CLSID\{1CB20BF0-BBAE-40A7-93F4-6435FF3D0411}
(Default) = ""

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Wow6432Node\CLSID\{1CB20BF0-BBAE-40A7-93F4-6435FF3D0411}\
InprocServer32
(Default) = "%User Temp%\{malware file name}.dll"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Wow6432Node\CLSID\{1CB20BF0-BBAE-40A7-93F4-6435FF3D0411}\
InprocServer32
ThreadingModel = "Apartment"

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
CToolbar
STUI = "{random characters}"

HKEY_CURRENT_USER\Software\CToolbar
DM_FOLDER = "%User Profile%\Documents"

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
CToolbar\Export
TBR_BBEXMODE = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
CToolbar\Export
TBR_Home_Page = "http://www.{BLOCKED}r.com/?tbid="

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
CToolbar\Export
TBR_Home_Page_Info = "Crawler.com"

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
CToolbar\Export
TBR_SEARCH_PAGE_INFO = "Crawler.com"

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
CToolbar\Export
TBR_BROWSERBAR_DIALOG = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
CToolbar\Export
TBR_Home_Page_DEF = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
CToolbar\Export
TBR_SEARCH_DIALOG_DEF = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
CToolbar\Export
TBR_BROWSERBAR_DIALOG_DEF = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
CToolbar\Export
TBR_SEARCH_OVERRIDE = ""

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
CToolbar\Export
TBR_SEARCH_DIALOG = "1"

HKEY_CURRENT_USER\Software\CToolbar
KImport_Hash = "{random characters}"

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
CToolbar
INSTALLUSER = "{username}"

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
Microsoft\Windows\CurrentVersion\
explorer\Browser Helper Objects\{1CB20BF0-BBAE-40A7-93F4-6435FF3D0411}
(Default) = ""

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
Microsoft\Windows\CurrentVersion\
explorer\Browser Helper Objects\{1CB20BF0-BBAE-40A7-93F4-6435FF3D0411}
NoExplorer = "1"

HKEY_CURRENT_USER\Software\CToolbar
LastDll = "\x022+.+-+62"

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
Microsoft\Internet Explorer\MAIN
IEWatsonEnabled = "0"

HKEY_CURRENT_USER\Software\CToolbar
CSHOW = "C"

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
Microsoft\Windows\CurrentVersion\
Installer\UserData\Crawler
C = "C"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Wow6432Node\CLSID\{4B3803EA-5230-4DC3-A7FC-33638F3D3542}
(Default) = "toolbar"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Wow6432Node\CLSID\{4B3803EA-5230-4DC3-A7FC-33638F3D3542}\
InprocServer32
(Default) = "%User Temp%\{malware file name}.dll"

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
Microsoft\Internet Explorer\Toolbar
{4B3803EA-5230-4DC3-A7FC-33638F3D3542} = "\x00"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Wow6432Node\CLSID\{4B3803EA-5230-4DC3-A7FC-33638F3D3542}
(Default) = "&Crawler Toolbar"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Wow6432Node\CLSID\{4B3803EA-5230-4DC3-A7FC-33638F3D3542}\
InprocServer32
ThreadingModel = "Apartment"

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
CToolbar
AllowUseDefskin = "1"

It deletes the following registry keys:

HKEY_CURRENT_USER\Software\CToolbar\
FirstDone

Dropping Routine

This Adware drops the following files:

  • %User Temp%\confirm.dat
  • %User Temp%\adrkeys.dat

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.850

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 2

Close all opened browser windows

Step 3

Delete this registry value

[ Learn More ]

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\SOFTWARE\Classes\Wow6432Node\CLSID\{4D25FB7A-8902-4291-960E-9ADA051CFBBF}
    • (Default) = ""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Wow6432Node\CLSID\{4D25FB7A-8902-4291-960E-9ADA051CFBBF}\InprocServer32
    • (Default) = "%User Temp%\{malware file name}.dll"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Wow6432Node\CLSID\{4D25FB7A-8902-4291-960E-9ADA051CFBBF}\InprocServer32
    • ThreadingModel = "Apartment"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\{malware file name}.R404Pro
    • (Default) = ""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\{malware file name}.R404Pro\Clsid
    • (Default) = "{4D25FB7A-8902-4291-960E-9ADA051CFBBF}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Wow6432Node\CLSID\{4D25FB7A-8902-4291-960E-9ADA051CFBBF}\ProgID
    • (Default) = "{malware file name}.R404Pro"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\PROTOCOLS\Handler\tbr
    • (Default) = "tbr"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\PROTOCOLS\Handler\tbr
    • CLSID = "{4D25FB7A-8902-4291-960E-9ADA051CFBBF}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Wow6432Node\CLSID\{1CB20BF0-BBAE-40A7-93F4-6435FF3D0411}
    • (Default) = ""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Wow6432Node\CLSID\{1CB20BF0-BBAE-40A7-93F4-6435FF3D0411}\InprocServer32
    • (Default) = "%User Temp%\{malware file name}.dll"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Wow6432Node\CLSID\{1CB20BF0-BBAE-40A7-93F4-6435FF3D0411}\InprocServer32
    • ThreadingModel = "Apartment"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\CToolbar
    • STUI = "{random characters}"
  • In HKEY_CURRENT_USER\Software\CToolbar
    • DM_FOLDER = "%User Profile%\Documents"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\CToolbar\Export
    • TBR_BBEXMODE = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\CToolbar\Export
    • TBR_Home_Page = "http://www.{BLOCKED}r.com/?tbid="
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\CToolbar\Export
    • TBR_Home_Page_Info = "Crawler.com"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\CToolbar\Export
    • TBR_SEARCH_PAGE_INFO = "Crawler.com"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\CToolbar\Export
    • TBR_BROWSERBAR_DIALOG = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\CToolbar\Export
    • TBR_Home_Page_DEF = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\CToolbar\Export
    • TBR_SEARCH_DIALOG_DEF = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\CToolbar\Export
    • TBR_BROWSERBAR_DIALOG_DEF = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\CToolbar\Export
    • TBR_SEARCH_OVERRIDE = ""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\CToolbar\Export
    • TBR_SEARCH_DIALOG = "1"
  • In HKEY_CURRENT_USER\Software\CToolbar
    • KImport_Hash = "{random characters}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\CToolbar
    • INSTALLUSER = "{username}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\explorer\Browser Helper Objects\{1CB20BF0-BBAE-40A7-93F4-6435FF3D0411}
    • (Default) = ""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\explorer\Browser Helper Objects\{1CB20BF0-BBAE-40A7-93F4-6435FF3D0411}
    • NoExplorer = "1"
  • In HKEY_CURRENT_USER\Software\CToolbar
    • LastDll = "\x022+.+-+62"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\MAIN
    • IEWatsonEnabled = "0"
  • In HKEY_CURRENT_USER\Software\CToolbar
    • CSHOW = "C"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Installer\UserData\Crawler
    • C = "C"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Wow6432Node\CLSID\{4B3803EA-5230-4DC3-A7FC-33638F3D3542}
    • (Default) = "toolbar"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Wow6432Node\CLSID\{4B3803EA-5230-4DC3-A7FC-33638F3D3542}\InprocServer32
    • (Default) = "%User Temp%\{malware file name}.dll"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\Toolbar
    • {4B3803EA-5230-4DC3-A7FC-33638F3D3542} = "\x00"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Wow6432Node\CLSID\{4B3803EA-5230-4DC3-A7FC-33638F3D3542}
    • (Default) = "&Crawler Toolbar"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Wow6432Node\CLSID\{4B3803EA-5230-4DC3-A7FC-33638F3D3542}\InprocServer32
    • ThreadingModel = "Apartment"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\CToolbar
    • AllowUseDefskin = "1"

Step 4

Search and delete these components

[ Learn More ]
There may be some components that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %User Temp%\confirm.dat
  • %User Temp%\adrkeys.dat

Step 5

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %User Temp%\TBR5LanguageAct
  • %User Temp%\Languages

Step 6

Scan your computer with your Trend Micro product to delete files detected as Adware.Win32.CToolBar.AA. 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 the following Trend Micro Support pages for more information:

Step 7

Restore these deleted registry keys/values from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

  • In HKEY_CURRENT_USER\Software\CToolbar
    • FirstDone


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