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TROJ_FAKEFLDR.I

October 09, 2012
 Analysis by: Michael Cabel
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • 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.

It executes then deletes itself afterward.

  TECHNICAL DETAILS

File Size:

1,011,200 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

07 Nov 2011

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 files:

  • %User Temp%\autoexec.bat
  • %User Temp%\ziplib32.dll
  • %Current Folder%\y‚²ŽQlzAPEC‚ÉŠÖ‚·‚鎑—¿\y‚²ŽQlzAPEC‚ÉŠÖ‚·‚鎑—¿.pdf

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

It creates the following folders:

  • %Current Folder%\y‚²ŽQlzAPEC‚ÉŠÖ‚·‚鎑—¿

It executes then deletes itself afterward.

Other System Modifications

This Trojan adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Netman
Start = "2"

(Note: The default value data of the said registry entry is 3.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Netman\Parameters
ServiceDll = "%User Temp%\ziplib32.dll"

(Note: The default value data of the said registry entry is %System%\netman.dll.)

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.556.06

FIRST VSAPI PATTERN DATE:

07 Nov 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

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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Netman\Parameters
    • From: ServiceDll = "%User Temp%\ziplib32.dll"
      To: ServiceDll = "%System%\netman.dll"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Netman
    • From: Start = "2"
      To: Start = "3"

Step 3

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.
  • %Current Folder%\y‚²ŽQlzAPEC‚ÉŠÖ‚·‚鎑—¿

Step 4

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.

  • %User Temp%\autoexec.bat
  • %User Temp%\ziplib32.dll

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_FAKEFLDR.I. 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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