ALIASES:

TrojanDownloader:Win32/Delf.TV (Microsoft); Generic.dx (McAfee); Trojan.Dropper (Symantec); PAK:PE_Patch.PECompact, PAK:PecBundle, PAK:PECompact, Trojan-Downloader.Win32.Ieser.z (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Generic.586544 (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: 309,252 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 28 Apr 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.

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\{16C6167B-FED4-4CEE-8951-134C9A345DA2}

Other System Modifications

This Trojan deletes the following files:

  • AUTOEXEC.BAT
  • boot.ini
  • CONFIG.SYS
  • Documents and Settings
  • IO.SYS
  • MSDOS.SYS
  • NTDETECT.COM
  • ntldr
  • pagefile.sys
  • Program Files
  • RECYCLER
  • sysprep.inf
  • System Volume Information
  • vcredist_x86.exe
  • WINDOWS

It adds the following registry keys:

HKEY_CLASSES_ROOT\CLSID\{16C6167B-FED4-4CEE-8951-134C9A345DA2}

HKEY_CLASSES_ROOT\CLSID\{16C6167B-FED4-4CEE-8951-134C9A345DA2}\
InprocServer32

HKEY_CLASSES_ROOT\immdtqupui.TIEBHOCom

HKEY_CLASSES_ROOT\immdtqupui.TIEBHOCom\Clsid

HKEY_CLASSES_ROOT\CLSID\{16C6167B-FED4-4CEE-8951-134C9A345DA2}\
ProgID

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{16C6167B-FED4-4CEE-8951-134C9A345DA2}\InprocServer32
ThreadingModel = "Apartment"

Dropping Routine

This Trojan drops the following files:

  • %System%\immdtqupui.dll
  • %System%\sssss.exe

(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.)

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

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_CLASSES_ROOT\CLSID
    • {16C6167B-FED4-4CEE-8951-134C9A345DA2}
  • In HKEY_CLASSES_ROOT\CLSID\{16C6167B-FED4-4CEE-8951-134C9A345DA2}
    • InprocServer32
  • In HKEY_CLASSES_ROOT
    • immdtqupui.TIEBHOCom
  • In HKEY_CLASSES_ROOT\immdtqupui.TIEBHOCom
    • Clsid
  • In HKEY_CLASSES_ROOT\CLSID\{16C6167B-FED4-4CEE-8951-134C9A345DA2}
    • ProgID

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_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{16C6167B-FED4-4CEE-8951-134C9A345DA2}\InprocServer32
    • ThreadingModel = "Apartment"

Step 5

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%\immdtqupui.dll
  • %System%\sssss.exe

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_IESER.AB. 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 7

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • AUTOEXEC.BAT
  • boot.ini
  • CONFIG.SYS
  • Documents and Settings
  • IO.SYS
  • MSDOS.SYS
  • NTDETECT.COM
  • ntldr
  • pagefile.sys
  • Program Files
  • RECYCLER
  • sysprep.inf
  • System Volume Information
  • vcredist_x86.exe
  • WINDOWS


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