Analysis by: Christopher Daniel So
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  TECHNICAL DETAILS

File Size: 1,289,331 bytes
File Type: PE
Memory Resident: Yes

Installation

This Trojan drops the following files:

  • %System%\com.run
  • %System%\dp1.fne
  • %System%\eAPI.fne
  • %System%\internet.fne
  • %System%\krnln.fnr
  • %System%\og.dll
  • %System%\og.edt
  • %System%\RegEx.fne
  • %System%\shell.fne
  • %System%\spec.fne
  • %System%\ul.dll
  • %User Temp%\E_4\com.run
  • %User Temp%\E_4\dp1.fne
  • %User Temp%\E_4\eAPI.fne
  • %User Temp%\E_4\internet.fne
  • %User Temp%\E_4\RegEx.fne
  • %User Temp%\E_4\shell.fne
  • %User Temp%\E_4\spec.fne
  • %User Temp%\History\History.IE5\desktop.ini
  • %User Temp%\TEMPORARY INTERNET FILES\Content.IE5\BR0XA91N\desktop.ini
  • %User Temp%\TEMPORARY INTERNET FILES\Content.IE5\CH2N4PQR\desktop.ini
  • %User Temp%\TEMPORARY INTERNET FILES\Content.IE5\CHEF41EF\desktop.ini
  • %User Temp%\TEMPORARY INTERNET FILES\Content.IE5\desktop.ini
  • %User Temp%\TEMPORARY INTERNET FILES\Content.IE5\O1IV85U3\desktop.ini

(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.. %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.)

Other System Modifications

This Trojan modifies the following registry entries:

HKEY_CURRENT_USER\SOFTWARE\MICROSOFT\
Windows\CURRENTVERSION\Explorer
FaultCount = "0"

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

HKEY_CURRENT_USER\SOFTWARE\MICROSOFT\
Windows\CURRENTVERSION\Explorer
FaultTime = "0"

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

Other Details

This Trojan does the following:

  • It modifies the following file(s):
    • %Temporary Internet Files%\desktop.ini

  SOLUTION

Minimum Scan Engine: 8.900

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

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%\com.run
  • %System%\dp1.fne
  • %System%\eAPI.fne
  • %System%\internet.fne
  • %System%\krnln.fnr
  • %System%\og.dll
  • %System%\og.edt
  • %System%\RegEx.fne
  • %System%\shell.fne
  • %System%\spec.fne
  • %System%\ul.dll
  • %User Temp%\E_4\com.run
  • %User Temp%\E_4\dp1.fne
  • %User Temp%\E_4\eAPI.fne
  • %User Temp%\E_4\internet.fne
  • %User Temp%\E_4\RegEx.fne
  • %User Temp%\E_4\shell.fne
  • %User Temp%\E_4\spec.fne
  • %User Temp%\History\History.IE5\desktop.ini
  • %User Temp%\TEMPORARY INTERNET FILES\Content.IE5\BR0XA91N\desktop.ini
  • %User Temp%\TEMPORARY INTERNET FILES\Content.IE5\CH2N4PQR\desktop.ini
  • %User Temp%\TEMPORARY INTERNET FILES\Content.IE5\CHEF41EF\desktop.ini
  • %User Temp%\TEMPORARY INTERNET FILES\Content.IE5\desktop.ini
  • %User Temp%\TEMPORARY INTERNET FILES\Content.IE5\O1IV85U3\desktop.ini

Step 3

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
    • From: FaultCount = 0
      To: FaultCount = 1
  • In HKEY_CURRENT_USER\SOFTWARE\MICROSOFT\Windows\CURRENTVERSION\Explorer
    • From: FaultTime = 0
      To: FaultTime = 2946f4

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_FLYSTUD.SMZ. 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 5

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.

  •  %Temporary Internet Files%\desktop.ini


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