TROJ_LMIR.A

Malware type: Trojan

Aliases: Trojan-PSW.Win32.Lmir.xm (Kaspersky), Generic.ca (McAfee), TR/PSW.Lmir.XM.2 (Avira),

In the wild: No

Destructive: No

Language: English

Platform: Windows 95, 98, ME, NT, 2000, XP

Encrypted: No

Overall risk rating:

Reported infections:

Damage potential:

Medium

Distribution potential:

Low

Description: 

Upon execution, it drops copies of itself in the Windows system folder using the following filenames:

  • Microsoft.exe
  • system32.exe
  • windows.exe

It then looks for a certain process, which is most probably its backdoor server component. It reports back to its author via email using its own Simple Mail Transfer Protocol (SMTP) engine.

It creates a registry entry to ensure its automatic execution at every system startup.

It also modifies another registry entry so that its other dropped copy, SYSTEM32.EXE, is executed whenever a text file is opened using Windows Explorer:

This Trojan runs on Windows 95, 98, ME, NT, 2000 and XP.

For additional information about this threat, see:

Description created: Jul. 21, 2004 12:50:01 AM GMT -0800
Description updated: Mar. 21, 2005 8:04:10 PM GMT -0800


TECHNICAL DETAILS


Size of malware: 223,744 Bytes

Initial samples received on: Jul 21, 2004

Details:

Installation and Autostart Technique

Upon execution, it drops copies of itself in the Windows system folder using the following filenames:

  • Microsoft.exe
  • system32.exe
  • windows.exe

It then looks for a certain process, which is most probably its backdoor server component. It reports back to its author via email using its own Simple Mail Transfer Protocol (SMTP) engine.

It creates the following registry entry to ensure its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\Windows\
CurrentVersion\RunOnce
windows update = "%System%\Microsoft.exe"

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 95, 98 and ME, C:\WINNT\System32 on Windows NT and 2000, and C:\Windows\System32 on Windows XP.)

It also modifies the following registry entry so that its other dropped copy, SYSTEM32.EXE, is executed whenever a text file is opened using Windows Explorer:

HKEY_CLASSES_ROOT\txtfile\shell\open\command

Other Details

This UPX-compressed Trojan is created using Borland Delphi.





Analysis by: Glenn Lugod

Revision History:

First pattern file version: 2.320.04
First pattern file release date: Jul 21, 2004

SOLUTION


Minimum scan engine version needed: 6.810

Pattern file needed: 7.852.13

Pattern release date: Feb 22, 2011


Important note: The "Minimum scan engine" refers to the earliest Trend Micro scan engine version guaranteed to detect this threat. However, Trend Micro strongly recommends that you update to the latest version in order to get comprehensive protection. Download the latest scan engine here.

Solution:

Terminating the Malware Program

This procedure terminates the running malware process.

  1. Open Windows Task Manager.
    � On Windows 95, 98, and ME, press
    CTRL%20ALT%20DELETE
    � On Windows NT, 2000, and XP, press
    CTRL%20SHIFT%20ESC, then click the Processes tab.
  2. In the list of running programs*, locate the process:
    MICROSOFT.EXE
  3. Select the malware process, then press either the End Task or the End Process button, depending on the version of Windows on your system.
  4. To check if the malware process has been terminated, close Task Manager, and then open it again.
  5. Close Task Manager.

*NOTE: On systems running Windows 95, 98, and ME, Windows Task Manager may not show certain processes. You can use a third party process viewer such as Process Explorer to terminate the malware process. Otherwise, continue with the next procedure, noting additional instructions.

Removing Autostart Entries from the Registry

Removing autostart entries from the registry prevents the malware from executing at startup.

  1. Open Registry Editor. Click Start>Run, type REGEDIT, then press Enter.
  2. In the left panel, double-click the following:
    HKEY_CURRENT_USER>Software>Microsoft>
    Windows>CurrentVersion>RunOnce
  3. In the right panel, locate and delete the entry:
    windows update = "%System%\Microsoft.exe"
    (Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 95, 98 and ME, C:\WINNT\System32 on Windows NT and 2000, and C:\Windows\System32 on Windows XP.)
  4. Close Registry Editor.

NOTE: If you were not able to terminate the malware process as described in the previous procedure, restart your system.

Addressing Registry Shell Spawning

This procedure prevents the malware from executing whenever a user opens files with certain extension names. It should restore the registry to its original settings.

  1. Click Start>Run.
  2. In the Open input box, type:
    command /c copy %WinDir%\regedit.exe regedit.com | regedit.com
  3. Press Enter.
  4. In the left panel, double-click the following:
    HKEY_CLASSES_ROOT>exefile>shell>open>command
  5. In the right panel, locate the registry entry:
    Default
  6. Check whether its value is the path and file name of the malware file.
  7. If the value is the malware file, right-click Default and select Modify to change its value.
  8. In the Value data input box, delete the existing value and type the default value:
    "NOTEPAD.EXE %1"
  9. Click OK.
  10. Close Registry Editor.
  11. Click Start>Run, then type:
    command /c del regedit.com
  12. Press Enter.

Additional Windows ME/XP Cleaning Instructions

Running Trend Micro Antivirus

Scan your system with Trend Micro antivirus and delete all files detected as TROJ_LMIR.A. To do this, Trend Micro customers must download the latest pattern file and scan their system. Other users can use HouseCall, Trend Micro�s free online virus scanner.


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