ALIASES:

Trojan:Win32/Meredrop (Microsoft); Generic Dropper!fff (McAfee); Suspicious.MH690 (Symantec); Trojan-Dropper.Win32.Agent.ahfp (Kaspersky); Virtumonde.a (Sunbelt); Trojan.Dropper.Vundo.S (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan 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: 303,104 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 01 Jan 2013

Arrival Details

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Autostart Technique

This Trojan 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\{CC628875-53FE-4DE3-9CA8-E61652820398}

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\SOFTWARE\Win32s

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\cpnds

HKEY_CLASSES_ROOT\CLSID\{CC628875-53FE-4DE3-9CA8-E61652820398}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{CC628875-53FE-4DE3-9CA8-E61652820398}\InprocServer32

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Win32s
AID = "105"

HKEY_CURRENT_USER\Software\Win32s
TID = "7"

HKEY_CURRENT_USER\Software\Win32s
FRY = "7dc"

HKEY_CURRENT_USER\Software\Win32s
FRM = "c"

HKEY_CURRENT_USER\Software\Win32s
FRD = "a"

HKEY_CURRENT_USER\Software\Win32s
FRH = "b"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
EnableBalloonTips = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
VisualEffects\TooltipAnimation
SetWindowPos = "HwndInsertAfter, Hwnd_Top"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
VisualEffects\TooltipAnimation
SetForegroundWindow = "1"

HKEY_CURRENT_USER\Software\Win32s
C1P1 = "7dc"

HKEY_CURRENT_USER\Software\Win32s
C1P2 = "c"

HKEY_CURRENT_USER\Software\Win32s
C1P3 = "a"

HKEY_CURRENT_USER\Software\Win32s
C1P4 = "b"

HKEY_CURRENT_USER\Software\Win32s
C1P5 = "2"

HKEY_CURRENT_USER\Software\Win32s
C2P1 = "7dc"

HKEY_CURRENT_USER\Software\Win32s
C2P2 = "c"

HKEY_CURRENT_USER\Software\Win32s
C2P3 = "a"

HKEY_CURRENT_USER\Software\Win32s
C2P4 = "b"

HKEY_CURRENT_USER\Software\Win32s
C2P5 = "2"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\cpnds
Asynchronous = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\cpnds
DllName = "%Program Files%\Common Files\System\cpnds.dll"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\cpnds
Impersonate = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\cpnds
Startup = "SysLogon"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\cpnds
Logoff = "SysLogoff"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{CC628875-53FE-4DE3-9CA8-E61652820398}\InprocServer32
ThreadingModel = "Both"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UpdatesDisableNotify = "1"

It deletes the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
SysUpd

Dropping Routine

This Trojan drops the following files:

  • %Program Files%\Common Files\System\cpnds.dll

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.300

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

Close all opened browser windows

Step 3

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_CURRENT_USER\SOFTWARE
    • Win32s
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify
    • cpnds
  • In HKEY_CLASSES_ROOT\CLSID
    • {CC628875-53FE-4DE3-9CA8-E61652820398}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{CC628875-53FE-4DE3-9CA8-E61652820398}
    • InprocServer32

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_CURRENT_USER\Software\Win32s
    • AID = "105"
  • In HKEY_CURRENT_USER\Software\Win32s
    • TID = "7"
  • In HKEY_CURRENT_USER\Software\Win32s
    • FRY = "7dc"
  • In HKEY_CURRENT_USER\Software\Win32s
    • FRM = "c"
  • In HKEY_CURRENT_USER\Software\Win32s
    • FRD = "a"
  • In HKEY_CURRENT_USER\Software\Win32s
    • FRH = "b"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • EnableBalloonTips = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\VisualEffects\TooltipAnimation
    • SetWindowPos = "HwndInsertAfter, Hwnd_Top"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\VisualEffects\TooltipAnimation
    • SetForegroundWindow = "1"
  • In HKEY_CURRENT_USER\Software\Win32s
    • C1P1 = "7dc"
  • In HKEY_CURRENT_USER\Software\Win32s
    • C1P2 = "c"
  • In HKEY_CURRENT_USER\Software\Win32s
    • C1P3 = "a"
  • In HKEY_CURRENT_USER\Software\Win32s
    • C1P4 = "b"
  • In HKEY_CURRENT_USER\Software\Win32s
    • C1P5 = "2"
  • In HKEY_CURRENT_USER\Software\Win32s
    • C2P1 = "7dc"
  • In HKEY_CURRENT_USER\Software\Win32s
    • C2P2 = "c"
  • In HKEY_CURRENT_USER\Software\Win32s
    • C2P3 = "a"
  • In HKEY_CURRENT_USER\Software\Win32s
    • C2P4 = "b"
  • In HKEY_CURRENT_USER\Software\Win32s
    • C2P5 = "2"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\cpnds
    • Asynchronous = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\cpnds
    • DllName = "%Program Files%\Common Files\System\cpnds.dll"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\cpnds
    • Impersonate = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\cpnds
    • Startup = "SysLogon"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\cpnds
    • Logoff = "SysLogoff"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{CC628875-53FE-4DE3-9CA8-E61652820398}\InprocServer32
    • ThreadingModel = "Both"

Step 5

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • AntiVirusDisableNotify = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • FirewallDisableNotify = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • UpdatesDisableNotify = "1"

Step 6

Search and delete this file

[ Learn More ]
There may be some files 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.
  • %Program Files%\Common Files\System\cpnds.dll

Step 7

Scan your computer with your Trend Micro product to delete files detected as TROJ_DROPPER.DIQ. 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.

Step 8

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\Microsoft
    • SysUpd


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