PE_ELICOP.A

May 23, 2015
 Analysis by: Francis Xavier Antazo
 PLATFORM:

Windows

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

  • Threat Type: File infector

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Infects files, Downloaded from the Internet, Dropped by other malware

This file infector arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It infects files by overwriting code in the entry point and saving the overwritten code in the virus body. It then appends the virus body to the host file.

  TECHNICAL DETAILS

File Size:

613,376 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

02 Aug 2015

Arrival Details

This file infector 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 file infector drops the following files:

  • C:\test\xp.ini (encrypted copy of xp.dll)
  • C:\test\vista.ini (encrypted copy of vista.dll)
  • C:\test\7-32.ini (encrypted copy of 7-32.dll)
  • C:\test\7-64.ini (encrypted copy of 7-64.dll)
  • %All Users Profile%\Documents\print.dll ( copy of %System%\dllcache\user32.dll )
  • %User Profile%\Avast\winsta32.dll ( copy of %All Users Profile%\Documents\tempdel2014 )
  • %User Profile%\Windows Settings\winsta32.bat ( will load winsta32.dll using regsvr32.exe )

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

It drops the following non-malicious files:

  • %System%\dllcache\user32.ini [encrypted copy of local user32.dll]
  • %Windows%\ServicePackFiles\i386\user32.ini [encrypted copy of local user32.dll]
  • %System%\user32.ini [encrypted copy of local user32.dll]
  • %Windows%\SysWOW64\user32.ini [encrypted copy of local user32.dll]

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

It adds the following processes:

  • svchost.exe

It injects codes into the following process(es):

  • explorer.exe
  • created svchost.exe

Other System Modifications

This file infector adds the following registry keys:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\sr\Parameters

HKEY_CURRENT_USER\Software\Microsoft\
Winodws\CurrentVersion\Explorer\
User Shell Folders

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\Current Version\Winlogon

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "Explorer.exe, %User Profile%\Windows Settings\winsta32.bat"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
User Shell Folders
Startup = "%User Profile%\Windows Settings"

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\sr\Parameters
FirstRun = 1

File Infection

This file infector infects the following files:

  • C:\test\xp.dll
  • C:\test\vista.dll
  • C:\test\7-32.dll
  • C:\test\7-64.dll
  • %System%\dllcache\user32.dll (if the affected system is 32 Bit)
  • %Windows%\ServicePackFiles\i386\user32.dll (if the affected system is 32 Bit)
  • %System%\user32.dll (if the affected system is 32 Bit)
  • %Windows%\SysWOW64\user32.dll (if the affected system is 64 Bit)

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

It overwrites code found in the entry point of a target file. It then appends the virus body to the target file. The overwritten code is saved in the virus body.

  SOLUTION

Minimum Scan Engine:

9.750

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

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\System\CurrentControlSet\Services\sr\Parameters
    • FirstRun = "1"
  • In HKEY_CURRENT_USER\Software\mcirosft\Windows\CurrentVersion\Explorer\User Shell Folders
    • Start = "User Profile%\Windows Settings"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Winlogon
    • Shell = "Explorer.exe, %User Profile%\Windows Settings\winsta32.bat"

Step 5

Search and delete this file

[ Learn More ]
There may be some 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.
  • %All Users Profile%\Documents\print32.dll
  • %User Profile%\Avast\winsta32.dll
  • %User Profile%\Windows Settings\winsta32.bat
  • %All Users Profile%\Documents\Report\index.html
  • %All Users Profile%\Documents\Report\pic.jpg

Step 6

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