Analysis by: Rhena Inocencio
ALIASES:

Trojan.Win32.Inject.mtvl (Kaspersky)

 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: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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

It modifies the Internet Explorer Zone Settings.

  TECHNICAL DETAILS

File Size: 248,320 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 09 May 2014

Arrival Details

This backdoor 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 backdoor drops the following copies of itself into the affected system and executes them:

  • %Program Files%\Common Files\UpdatesNotifier\{random filename}.exe (for versions other than Windows Vista/Windows 7)
  • {All Users Profile}\UpdatesNotifier\{random filename}.exe (for Windows Vista/Windows 7 only)

(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).)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
OrigNotifier = "%Program Files%\Common Files\UpdatesNotifier\{random filename}.exe" (for versions other than Windows Vista/Windows 7)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
OrigNotifier = "%Program Files%\Common Files\UpdatesNotifier\{random filename}.exe" (for versions other than Windows Vista/Windows 7)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
OrigNotifier = "{All Users Profile}\UpdatesNotifier\{random filename}.exe" (for Windows Vista/Windows 7 only)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
OrigNotifier = "{All Users Profile}\UpdatesNotifier\{random filename}.exe" (for Windows Vista/Windows 7 only)

Other System Modifications

This backdoor adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
{random filename}.exe

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
rstrui.exe
Debugger = "{5 random characters}.exe"

Web Browser Home Page and Search Page Modification

This backdoor modifies the Internet Explorer Zone Settings.

Other Details

This backdoor connects to the following possibly malicious URL:

  • {BLOCKED}g.su
  • {BLOCKED}i.su

  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

Scan your computer with your Trend Micro product and note files detected as BKDR_NEUREVT.Z

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
    • OrigNotifier = "%Program Files%\Common Files\UpdatesNotifier\{random filename}.exe" (for versions other than Windows Vista/Windows 7)
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • OrigNotifier = "%Program Files%\Common Files\UpdatesNotifier\{random filename}.exe" (for versions other than Windows Vista/Windows 7)
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • OrigNotifier = "{All Users Profile}\UpdatesNotifier\{random filename}.exe" (for Windows Vista/Windows 7 only)
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • OrigNotifier = "{All Users Profile}\UpdatesNotifier\{random filename}.exe" (for Windows Vista/Windows 7 only)
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\rstrui.exe
    • Debugger = "{5 random characters}.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\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
    • {random filename}.exe

Step 6

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