Analysis by: Karl Dominguez
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Adware

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This adware may be downloaded by other malware/grayware/spyware from remote sites.

It connects to certain URLs. It may do this to remotely inform a malicious user of its installation. It may also do this to download possibly malicious files onto the computer, which puts the computer at a greater risk of infection by other threats.

It displays advertisements on Internet browsers.

  TECHNICAL DETAILS

File Size: 909,312 bytes
File Type: DLL
Memory Resident: Yes
Initial Samples Received Date: 07 May 2011
Payload: Displays graphics/image, Drops files, Connects to URLs/Ips

Arrival Details

This adware may be downloaded by other malware/grayware/spyware from remote sites.

Autostart Technique

This adware adds the following registry keys to install itself as a Browser Helper Object (BHO):

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects\{FEBECA81-C23D-43A5-A2AD-AFE1FDB4408C}

Other System Modifications

This adware adds the following registry keys:

HKEY_CLASSES_ROOT\CLSID\{FEBECA80-C23D-43A5-A2AD-AFE1FDB4408C}

HKEY_CURRENT_USER\Software\IEBarProperties

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\SearchScopes

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\SearchScopes

HKEY_CLASSES_ROOT\CLSID\{FEBECA81-C23D-43A5-A2AD-AFE1FDB4408C}

It adds the following registry entries:

HKEY_CLASSES_ROOT\CLSID\{FEBECA80-C23D-43A5-A2AD-AFE1FDB4408C}
(default) = Tango

HKEY_CLASSES_ROOT\CLSID\{FEBECA80-C23D-43A5-A2AD-AFE1FDB4408C}\
InprocServer32
(default) = {malware path and file name}

HKEY_CLASSES_ROOT\CLSID\{FEBECA80-C23D-43A5-A2AD-AFE1FDB4408C}\
InprocServer32
ThreadingModel = Apartment

HKEY_CLASSES_ROOT\CLSID\{FEBECA80-C23D-43A5-A2AD-AFE1FDB4408C}\
Properties
Version = 78

HKEY_CLASSES_ROOT\CLSID\{FEBECA80-C23D-43A5-A2AD-AFE1FDB4408C}\
Properties
BuildName = 876994

HKEY_CLASSES_ROOT\CLSID\{FEBECA80-C23D-43A5-A2AD-AFE1FDB4408C}\
Properties
Ticket = 0

HKEY_CLASSES_ROOT\CLSID\{FEBECA80-C23D-43A5-A2AD-AFE1FDB4408C}\
TypeLib
(default) = {FDC037FD-5812-4D90-AC58-51F0FC4D4741}

HKEY_CLASSES_ROOT\CLSID\{FEBECA81-C23D-43A5-A2AD-AFE1FDB4408C}
(default) = Tango

HKEY_CLASSES_ROOT\CLSID\{FEBECA81-C23D-43A5-A2AD-AFE1FDB4408C}\
InprocServer32
(default) = {malware path and file name}

HKEY_CLASSES_ROOT\CLSID\{FEBECA81-C23D-43A5-A2AD-AFE1FDB4408C}\
InprocServer32
ThreadingModel = Apartment

HKEY_CLASSES_ROOT\CLSID\{FEBECA81-C23D-43A5-A2AD-AFE1FDB4408C}\
TypeLib
(default) = {FDC037FD-5812-4D90-AC58-51F0FC4D4741}

HKEY_CURRENT_USER\Software\IEBarProperties
ShowType = 1

HKEY_CURRENT_USER\Software\IEBarProperties
PopupCount = 0

HKEY_CURRENT_USER\Software\IEBarProperties
BlockEnable = 1

HKEY_CURRENT_USER\Software\IEBarProperties
WalkThrough = 0

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\SearchScopes
DefaultScope = {5F40D7C0-7AE2-4DDF-95DF-36CF762E0C55}

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\SearchScopes\{5F40D7C0-7AE2-4DDF-95DF-36CF762E0C55}
DisplayName = Search

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\SearchScopes\{5F40D7C0-7AE2-4DDF-95DF-36CF762E0C55}
URL = http://www.tangosearch.com/?q={searchTerms}&a=SEARCH

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\SearchScopes\{5F40D7C0-7AE2-4DDF-95DF-36CF762E0C55}
Codepage = fde9

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Use Custom Search URL = 1

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Search Bar = http://www.tangosearch.com/?useie5=1&q=

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Toolbar\WebBrowser
ITBar7Layout = 0

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Toolbar\WebBrowser
{FEBECA80-C23D-43A5-A2AD-AFE1FDB4408C} = {hex values}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\SearchScopes
DefaultScope = {5F40D7C0-7AE2-4DDF-95DF-36CF762E0C55}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\SearchScopes\{5F40D7C0-7AE2-4DDF-95DF-36CF762E0C55}
DisplayName = Search

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\SearchScopes\{5F40D7C0-7AE2-4DDF-95DF-36CF762E0C55}
URL = http://www.tangosearch.com/?q={searchTerms}&a=SEARCH

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\SearchScopes\{5F40D7C0-7AE2-4DDF-95DF-36CF762E0C55}
Codepage = fde9

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Use Custom Search URL = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Search Bar = http://www.tangosearch.com/?useie5=1&q=

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Toolbar
{FEBECA80-C23D-43A5-A2AD-AFE1FDB4408C} = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects\{FEBECA81-C23D-43A5-A2AD-AFE1FDB4408C}
(default) = Tango

Download Routine

This adware connects to the following malicious URLs:

  • http://{BLOCKED}toolbar.com

Adware Routine

This adware displays advertisements on Internet browsers.

Other Details

This adware adds the following registry entries to add an uninstall option to the Control Panel:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
{FEBECA80-C23D-43A5-A2AD-AFE1FDB4408C}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
{FEBECA80-C23D-43A5-A2AD-AFE1FDB4408C}
DisplayName = Tango

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
{FEBECA80-C23D-43A5-A2AD-AFE1FDB4408C}
UninstallString = mshta.exe http://remove.tangotoolbar.com/

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 1.176.14
FIRST VSAPI PATTERN DATE: 07 May 2011

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Scan your computer with your Trend Micro product and note files detected as ADW_DANCEBAR

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Delete this registry key

[ 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\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects
    • {FEBECA81-C23D-43A5-A2AD-AFE1FDB4408C}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
    • {FEBECA80-C23D-43A5-A2AD-AFE1FDB4408C}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer
    • SearchScopes
  • In HKEY_CURRENT_USER\Software
    • IEBarProperties
  • In HKEY_CLASSES_ROOT\CLSID
    • {FEBECA80-C23D-43A5-A2AD-AFE1FDB4408C}
  • In HKEY_CLASSES_ROOT\CLSID
    • {FEBECA81-C23D-43A5-A2AD-AFE1FDB4408C}
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer
    • SearchScopes

Step 5

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_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • Use Custom Search URL = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • Search Bar = http://www.tangosearch.com/?useie5=1&q=
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Toolbar\WebBrowser
    • ITBar7Layout = 0
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Toolbar\WebBrowser
    • {FEBECA80-C23D-43A5-A2AD-AFE1FDB4408C} = {hex values}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main
    • Use Custom Search URL = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main
    • Search Bar = http://www.tangosearch.com/?useie5=1&q=
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Toolbar
    • {FEBECA80-C23D-43A5-A2AD-AFE1FDB4408C} = 0

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as ADW_DANCEBAR. 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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