ALIASES:

Trojan:Win32/VB (Microsoft); Generic.dx!fh (McAfee); Downloader (Symantec); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Generic.1922498 (FSecure)

 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.

  TECHNICAL DETAILS

Tamaño del archivo 303,104 bytes
Tipo de archivo EXE
Residente en memoria Yes
Fecha de recepción de las muestras iniciales 09 Dec 2012

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
lrwab = "%Program Files%\Outlook Express\lrwab.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
y9x7oo7dm5j4lf\fqmyn2rz308kuz0p

It adds the following registry entries:

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
y9x7oo7dm5j4lf\fqmyn2rz308kuz0p
d45swaf8uqrqtjnss = "%Program Files%\Outlook Express\lrwab.exe"

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
y9x7oo7dm5j4lf\fqmyn2rz308kuz0p
vxqsm4o97vn1voy5tk = "%Program Files%\Outlook Express\krsetup50.exe"

Dropping Routine

This Trojan drops the following files:

  • %System Root%\h7lzvnx2.txt
  • %Program Files%\Outlook Express\lrwab.exe
  • %Program Files%\Outlook Express\krsetup50.exe

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %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).)

This report is generated via an automated analysis system.

  SOLUTION

Motor de exploración mínimo 9.300

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\VB and VBA Program Settings\y9x7oo7dm5j4lf
    • fqmyn2rz308kuz0p

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
    • lrwab = "%Program Files%\Outlook Express\lrwab.exe"
  • In HKEY_CURRENT_USER\Software\VB and VBA Program Settings\y9x7oo7dm5j4lf\fqmyn2rz308kuz0p
    • d45swaf8uqrqtjnss = "%Program Files%\Outlook Express\lrwab.exe"
  • In HKEY_CURRENT_USER\Software\VB and VBA Program Settings\y9x7oo7dm5j4lf\fqmyn2rz308kuz0p
    • vxqsm4o97vn1voy5tk = "%Program Files%\Outlook Express\krsetup50.exe"

Step 5

Search and delete these components

[ Learn More ]
There may be some components 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 Root%\h7lzvnx2.txt
  • %Program Files%\Outlook Express\lrwab.exe
  • %Program Files%\Outlook Express\krsetup50.exe

Step 6

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