WORM_MSIL.BR

October 09, 2013
 Analysis by: Sabrina Lei Sioting
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003, Windows Vista, Windows 7

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware, Propagates via removable drives

This worm arrives by connecting affected removable drives to a system. It 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:

102,400 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

03 Oct 2012

Arrival Details

This worm arrives by connecting affected removable drives to a system.

It 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 worm drops the following copies of itself into the affected system:

  • %User Startup%\svchost..exe

(Note: %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.)

Propagation

This worm drops the following copy(ies) of itself in all removable drives:

  • movies.exe

NOTES:

Upon execution, the malware checks the OS version of the affected machine. If it is Windows Vista or Windows 7, it drops the following copies of itself on the affected system:

  • %Desktop%\suchost..exe

(Note: %Desktop% is the current user's desktop, which is usually C:\Users\{user name}\Desktop on Windows Vista or Windows 7.)

If the OS version is not Windows Vista or Windows 7, it drops the following copies of itself on the affected system:

  • %Windows%\system\svchost..exe

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

For Windows Vista or Windows 7, %User Startup% is the current user's Startup folder, which is usually C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista or Windows 7.

It searches for folders in all removable drives then drops copies of itself inside the folder as {folder name}.EXE.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

9.438.03

FIRST VSAPI PATTERN DATE:

03 Oct 2012

VSAPI OPR PATTERN File:

9.439.00

VSAPI OPR PATTERN Date:

04 Oct 2012

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

Identify and terminate files detected as WORM_MSIL.BR

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

Scan your computer with your Trend Micro product to delete files detected as WORM_MSIL.BR. 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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