ALIASES:

Trojan:WinNT/Kernelpatch.A (Microsoft); Downloader.a!gn (McAfee); Trojan.Gen (Symantec); Trojan-Downloader.Win32.Geral.advk (Kaspersky); Trojan.Win32.KillAV.nmu (v) (not malicious) (Sunbelt); Gen:Variant.Graftor.20937 (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: 35,889 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 07 May 2012

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.

Installation

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

  • %Program Files%\Common Files\realteck\geoidy.pif

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

It creates the following folders:

  • %Program Files%\Common Files\realteck

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

Other System Modifications

This Trojan modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer
FaultCount = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer
FaultTime = "9162"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer
FaultCount = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer
FaultTime = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer
CleanShutdown = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\Imapi
LogSessionName = "stdout"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\Imapi
Active = "1"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\Imapi
ControlFlags = "1"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\Imapi\ImapiSvc
Guid = "8107d8e9-e323-49f5-bba2-abc35c243dca"

(Note: The default value data of the said registry entry is 8107d8e9-e323-49f5-bba2-abc35c243dca.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\Imapi\ImapiSvc
BitNames = "{random characters}"

(Note: The default value data of the said registry entry is ImapiDebugError ImapiDebugWarning ImapiDebugTrace ImapiDebugInfo ImapiDebugX ImapiDebugSort.)

It deletes the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
IEAK\GroupPolicy\PendingGPOs

Dropping Routine

This Trojan drops the following files:

  • %System%\32906.DLI
  • %System%\DeMb.dzn
  • %Temp%\yeln2z0r.TMP

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.. %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp or C:\WINNT\Temp.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.200

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

Restore this modified 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\Windows\CurrentVersion\Explorer
    • FaultCount = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer
    • FaultTime = "9162"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer
    • FaultCount = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer
    • FaultTime = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer
    • CleanShutdown = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\Imapi
    • From: LogSessionName = "stdout"
      To: LogSessionName = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\Imapi
    • From: Active = "1"
      To: Active = ""1""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\Imapi
    • From: ControlFlags = "1"
      To: ControlFlags = ""1""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\Imapi\ImapiSvc
    • From: Guid = "8107d8e9-e323-49f5-bba2-abc35c243dca"
      To: Guid = ""8107d8e9-e323-49f5-bba2-abc35c243dca""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\Imapi\ImapiSvc
    • From: BitNames = "{random characters}"
      To: BitNames = "" ImapiDebugError ImapiDebugWarning ImapiDebugTrace ImapiDebugInfo ImapiDebugX ImapiDebugSort""

Step 3

Search and delete these files

[ Learn More ]
There may be some component 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.
  • %System%\32906.DLI
  • %System%\DeMb.dzn
  • %Temp%\yeln2z0r.TMP

Step 4

Search and delete this folder

[ 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.
  • %Program Files%\Common Files\realteck

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_DLOADER.POK. 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 6

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\IEAK\GroupPolicy
    • PendingGPOs


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