PE_VIRUX.A

July 25, 2013
 ALIASES:

Virus:Win32/Virut.BN (Microsoft); W32.Virut.CF (Symantect); Virus.Win32.Virut.ce (Kaspersky)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: File infector

  • Destructiveness: No

  • Encrypted: No

  • 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.

It connects to Internet Relay Chat (IRC) servers.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

06 Feb 2009

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:

  • %Windows%\usbservice.exe

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

Autostart Technique

This file infector registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Usb Service 2.0
ImagePath = "%Windows%\usbservice.exe"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Usb Service 2.0
DisplayName = "Usb Service 2.0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Usb Service 2.0
Type = "110"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Usb Service 2.0
Start = "2"

Other System Modifications

This file infector adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
\??\%System%\winlogon.exe = "\??\%System%\winlogon.exe:*:enabled:@shell32.dll,-1"

Backdoor Routine

This file infector connects to any of the following Internet Relay Chat (IRC) servers:

  • irc.{BLOCKED}f.pl

HOSTS File Modification

This file infector adds the following strings to the Windows HOSTS file:

  • {BLOCKED}7.{BLOCKED}.0.1 {BLOCKED}eF.pl

Other Details

This file infector deletes the initially executed copy of itself

NOTES:
It may also connect to randomly generated domains for its C&C (command and control) server using a randomizing function, which is computed based on the system's current date and time. The generated domain is {6 random characters}.com.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

5.820.04

FIRST VSAPI PATTERN DATE:

06 Feb 2009

VSAPI OPR PATTERN File:

5.821.00

VSAPI OPR PATTERN Date:

06 Feb 2009

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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • Usb Service 2.0

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\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • \??\%System%\winlogon.exe = "\??\%System%\winlogon.exe:*:enabled:@shell32.dll,-1"

Step 5

Remove these strings added by the malware/grayware/spyware in the HOSTS file

[ Learn More ]
    • {BLOCKED}7.{BLOCKED}.0.1 {BLOCKED}eF.pl
"

Step 6

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