TROJ_MEREDROP.II

October 29, 2012
 Analysis by: Rhena Inocencio
 ALIASES:

Trojan.Spy.XXP (BitDefender), Trojan.Win32.Packer.Upack0.3.9 (ep) (Sunbelt), Trj/Pupack.A (Panda), W32/Agent.G!tr (Fortinet)

 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.

It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

  TECHNICAL DETAILS

File Size:

135,528 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

23 Dec 2008

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 adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Windows Update = "{Malware Path and File Name}.exe"

Dropping Routine

This Trojan drops the following files:

  • %System%\lsasvc.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.)

It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

Other Details

This Trojan adds and runs the following services:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\LSAService
ImagePath = "%System%\lsasvc.exe"

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

5.726.09

FIRST VSAPI PATTERN DATE:

23 Dec 2008

VSAPI OPR PATTERN File:

5.727.00

VSAPI OPR PATTERN Date:

24 Dec 2008

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

Scan your computer with your Trend Micro product and note files detected as TROJ_MEREDROP.II

Step 3

Restart in Safe Mode

[ Learn More ]

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\Microsoft\Windows\CurrentVersion\Run
    • Windows Update = "{Malware Path and File Name}.exe"

Step 5

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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • LSAService

Step 6

Search and delete this file

[ 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%\lsasvc.exe

Step 7

Search and delete the file detected as TROJ_MEREDROP.II

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files in the search result.

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_MEREDROP.II. 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.


Did this description help? Tell us how we did.