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PE_RAMNIT.HL-O

October 09, 2012
 Analysis by: Roland Marco Dela Paz
 ALIASES:

Trojan:Win32/Ramnit (Microsoft)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: File infector

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Infects files


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 is injected into all running processes to remain memory resident.

It connects to a website to send and receive information.

It also has rootkit capabilities, which enables it to hide its processes and files from the user.

  TECHNICAL DETAILS

File Size:

98,032 bytes

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

29 Feb 2012

Payload:

Compromises system security, Connects to URLs/IPs, Steals information, Modifies system registry, Drops files

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 Temp%\myactvgmnkbmhtdx.exe
  • %User Startup%\uqchowhg.exe
  • %Application Data%\mnkuetxp\uqchowhg.exe

(Note: %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.. %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.. %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)

It adds the following processes:

  • svchost.exe

It creates the following folders:

  • %Application Data%\mnkuetxp

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)

It is injected into all running processes to remain memory resident.

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
UqcHowhg = %Application Data%\mnkuetxp\uqchowhg.exe

It modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Userinit = %System%\userinit.exe,,%Application Data%\mnkuetxp\uqchowhg.exe

(Note: The default value data of the said registry entry is %System%\userinit.exe,.)

Other System Modifications

This file infector deletes the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\SafeBoot

File Infection

This file infector infects the following file types:

  • EXE
  • DLL

Backdoor Routine

This file infector connects to the following websites to send and receive information:

  • {BLOCKED}money2.com

Rootkit Capabilities

This file infector also has rootkit capabilities, which enables it to hide its processes and files from the user.

Stolen Information

This file infector saves the stolen information in the following file:

  • %Application Data%\{random1}.log - contains encrypted, stolen data
  • %Application Data%\{random2}.log - archive file that contains stolen cookies

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)

Other Details

This file infector connects to the following URL(s) to check for an Internet connection:

  • google.com
  • bing.com
  • yahoo.com

NOTES:

This file infector is capable of infecting files in shared networks, consequently allowing the malware to propagate across the network.

It steals cookies from the following software:

  • Chrome
  • Firefox
  • Internet Explorer
  • Opera
  • Safari
  • My SQL
  • Macromedia Flash Player

It also attempts to steal sensitive online banking information, such as user names and passwords. It does this by monitoring the browser activities of the affected system, specifically the address bar. When a user visits a site that it targets, it will then steal specific user inputs through malicious codes that it inserts to the user's browser. Financial sites targeted by this malware are declared in a configuration file that is issued by a remote malicious user. It is capable of executing the following commands:

  • Download and execute file(s)
  • Capture screenshot(s)
  • Update itself
  • Retrieve stolen cookies
  • Remove cookies
  • Send stolen information

Files infected by this malware are detected as PE_RAMNIT.HL.

  SOLUTION

Minimum Scan Engine:

9.200

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

Remove malware files dropped/downloaded by PE_RAMNIT.HL-O

    PE_RAMNIT.HL

Step 3

Identify and delete files detected as PE_RAMNIT.HL-O using either the Startup Disk or Recovery Console

[ Learn More ]

Step 4

Search and delete these folders

[ 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.  %Application Data%\mnkuetxp

Step 5

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.  %Application Data%\{random1}.log
%Application Data%\{random2}.log

Step 6

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
    • UqcHowhg = %Application Data%\mnkuetxp\uqchowhg.exe

Step 7

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: Userinit = %System%\userinit.exe,,%Application Data%\mnkuetxp\uqchowhg.exe
      To: Userinit = %System%\userinit.exe,

Step 8

Scan your computer with your Trend Micro product to delete files detected as PE_RAMNIT.HL-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.

NOTES:

To Restore Safe Boot Registry Settings:

  1. Open Notepad. To do this, click Start>Run, type Notepad in the text box provided, then press Enter.
  2. Copy and paste the following script:

    For Windows 2000:


    For Windows XP:


    For Windows 2003:
  3. Save this file as C:\RESTORE.REG..
  4. Click Start>Run again, type C:\RESTORE.REG in the text box provided, then press Enter.
  5. Click Yes at the prompt of the message box to execute the .REG file.


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