PE_RAMNIT.DEN2-O


 ALIASES:

Troj/Zbot-HSJ (Sophos) ,Found Luhe.Fiha.A (AVG) ,W32/Androm.AYKE!tr.bdr (Fortinet) ,Virus.Win32.Ramnit (Ikarus) ,Backdoor.Win32.Androm.bwkg (Kaspersky) ,Trojan:Win32/Ramnit (Microsoft) ,PWSZbot-FLW!1E3B19C7BEB8 (McAfee) ,a variant of Win32/Injector.AYKE trojan (Eset) ,Generic (Panda) ,Trojan.Win32.Generic!BT (Sunbelt)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: File infector

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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.

  TECHNICAL DETAILS

File Size:

581,662 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

06 Mar 2014

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 copies of itself into the affected system:

  • %User Profile%\My Documents\DCSCMIN\IMDCSC.exe

(Note: %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 file:

  • %Program Files%\Internet Explorer\dmlconf.dat

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

It creates the following folders:

  • %User Profile%\Application Data\dclogs
  • %User Profile%\My Documents\DCSCMIN

(Note: %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.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
DarkCometRAT = "%User Profile%\My Documents\DCSCMIN\IMDCSC.exe"

Other System Modifications

This file infector adds the following registry keys:

HKEY_CURRENT_USER\Software\DC3_FEXEC

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Program Files%\Internet Explorer\IEXPLORE.EXE = "%Program Files%\Internet Explorer\IEXPLORE.EXE:*:Enabled:internet Explorer"

File Infection

This file infector infects the following file types:

  • EXE
  • DLL
  • HTML

Other Details

This file infector connects to the following possibly malicious URL:

  • {BLOCKED}dmn.com

  SOLUTION

Minimum Scan Engine:

9.700

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

Restart in Safe Mode

[ Learn More ]

Step 3

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • DarkCometRAT = "%User Profile%\My Documents\DCSCMIN\IMDCSC.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %Program Files%\Internet Explorer\IEXPLORE.EXE = "%Program Files%\Internet Explorer\IEXPLORE.EXE:*:Enabled:internet Explorer"

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • DarkCometRAT = "%User Profile%\My Documents\DCSCMIN\IMDCSC.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %Program Files%\Internet Explorer\IEXPLORE.EXE = "%Program Files%\Internet Explorer\IEXPLORE.EXE:*:Enabled:internet Explorer"

Step 5

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.
  • %User Profile%\Application Data\dclogs
  • %User Profile%\My Documents\DCSCMIN

Step 6

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.
  • %Program Files%\Internet Explorer\dmlconf.dat

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as PE_RAMNIT.DEN2-O. 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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