TROJ_ADCLICK.DV


 ALIASES:

TrojanDownloader:Win32/Tracur.AG (Microsoft)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This Trojan may be dropped by other malware.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

DLL

Memory Resident:

No

Initial Samples Received Date:

18 Oct 2011

Payload:

Connects to URLs/IPs

Arrival Details

This Trojan may be dropped by the following malware:

  • TROJ_DROPPER.QNB

Installation

This Trojan drops the following copies of itself into the affected system:

  • %System Root%\Documents and Settings\All Users\Application Data\{random file name}.dll

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random file name} = "rundll32.exe "%System Root%\Documents and Settings\All Users\Application Data\{random file name}.dll",DllRegisterServer"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random string} Update = "rundll32 "%Application Data%\{random folder}\{random folder}Update\{random folder}updt32.dll",DllRegisterServer"

It 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\{040C4CD3-B51E-47BE-8144-8BD237D9E570}

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CLASSES_ROOT\.fsharproj

HKEY_CLASSES_ROOT\Cfbbbjkdkl

HKEY_CLASSES_ROOT\CLSID\{040C4CD3-B51E-47BE-8144-8BD237D9E570}

HKEY_CLASSES_ROOT\CLSID\{65a6cb5b-9677-4ff6-b079-2f8de13143c2}

HKEY_CLASSES_ROOT\Software\Cfbbbjkdkl

It adds the following registry entries:

HKEY_CLASSES_ROOT\CLSID\{040C4CD3-B51E-47BE-8144-8BD237D9E570}\
InprocServer32
(Default) = "%Application Data%\{random file name}.dll"

HKEY_CLASSES_ROOT\.fsharproj\PersistentHandler
(Default) = "{d1c2175c-2d1d-4d0a-93c5-b1f1e9e59d28}"

HKEY_CLASSES_ROOT\Cfbbbjkdkl\CLSID
(Default) = "{65a6cb5b-9677-4ff6-b079-2f8de13143c2}"

HKEY_CLASSES_ROOT\Software\Cfbbbjkdkl\
CLSID
(Default) = "{65a6cb5b-9677-4ff6-b079-2f8de13143c2}"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
XMLHTTP_UUID_Default = {random values}

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
DisableFirstRunCustomize = 1

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Check_Associations = "no"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
WarnonZoneCrossing = 0

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
GlobalUserOffline = 0

NOTES:

It connects to the following URL to inform the remote user about its installation:

  • http://{BLOCKED}.137.85/xml?a=2003&ip=self&kw=

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.506.09

FIRST VSAPI PATTERN DATE:

18 Oct 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

Remove the malware/grayware file that dropped/downloaded TROJ_ADCLICK.DV

    • TROJ_DROPPER.QNB

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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_CLASSES_ROOT\.fsharproj\PersistentHandler
    • (Default) = "{d1c2175c-2d1d-4d0a-93c5-b1f1e9e59d28}"
  • In HKEY_CLASSES_ROOT\Cfbbbjkdkl\CLSID
    • (Default) = "{65a6cb5b-9677-4ff6-b079-2f8de13143c2}"
  • In HKEY_CLASSES_ROOT\CLSID\{040C4CD3-B51E-47BE-8144-8BD237D9E570}\InprocServer32
    • (Default) = "%Application Data%\{random file name}.dll"
  • In HKEY_CLASSES_ROOT\Software\Cfbbbjkdkl\CLSID
    • (Default) = "{65a6cb5b-9677-4ff6-b079-2f8de13143c2}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • XMLHTTP_UUID_Default = {random values}
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • DisableFirstRunCustomize = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • Check_Associations = "no"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • WarnonZoneCrossing = 0
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • GlobalUserOffline = 0
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • {random file name} = "rundll32.exe "%System Root%\Documents and Settings\All Users\Application Data\{random file name}.dll",DllRegisterServer"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • {random string} Update = "rundll32 "%Application Data%\{random folder}\{random folder}Update\{random folder}updt32.dll",DllRegisterServer"

Step 5

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_CLASSES_ROOT
    • .fsharproj
  • In HKEY_CLASSES_ROOT
    • Cfbbbjkdkl
  • In HKEY_CLASSES_ROOT\CLSID
    • {040C4CD3-B51E-47BE-8144-8BD237D9E570}
  • In HKEY_CLASSES_ROOT\CLSID
    • {65a6cb5b-9677-4ff6-b079-2f8de13143c2}
  • In HKEY_CLASSES_ROOT\Software
    • Cfbbbjkdkl
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects
    • {040C4CD3-B51E-47BE-8144-8BD237D9E570}

Step 6

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

NOTES:

RECOMMENDATIONS:

  • Always keep pattern files/engine up-to-date.
  • Avoid downloading crack applications.
  • Avoid opening e-mail attachments unless expected.
  • Avoid visiting un-trusted sites that may redirect or download malware into the system.
  • Back up data regularly.
  • Be aware of social engineering attacks to be safe.
  • Block malware related websites.
  • Configure your email server to block or remove email that contains file attachments such as .vbs, .bat, .exe, .pif and .scr files.
  • Enable firewall to protect against web threats.
  • When a computer is compromised, isolate it immediately from the network.


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