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WORM_AUTORUN.SLRF

September 09, 2016
 Analysis by: Jennifer Gumban
 ALIASES:

Worm.VBS.Agent.fm (Kaspersky)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Via physical/removable drives, Downloaded from the Internet, Dropped by other malware


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.

It drops copies of itself in all removable and physical drives found in the system.

It modifies the Internet Explorer Zone Settings.

It connects to certain websites to send and receive information.

  TECHNICAL DETAILS

File Size:

225,280 bytes

File Type:

Other

Memory Resident:

No

Initial Samples Received Date:

21 Jul 2016

Payload:

Connects to URLs/IPs, Drops files

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:

  • %Application Data%\Microsoft Office\Microsoft Word.WsF

    It sets the file to hidden

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
Microsoft Word = "wscript.exe //D "%Application Data%\Microsoft Office\Microsoft Word.WsF""

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Microsoft Word = "wscript.exe //D "%Application Data%\Microsoft Office\Microsoft Word.WsF""

Other System Modifications

This worm adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft Word
{default} = {date of installation}

Propagation

This worm drops copies of itself in all removable and physical drives found in the system.

Web Browser Home Page and Search Page Modification

This worm modifies the Internet Explorer Zone Settings.

Other Details

This worm connects to the following website to send and receive information:

  • http://{BLOCKED}o.{BLOCKED}e.com:862/is-rinoy
  • http://{BLOCKED}o.{BLOCKED}c.net:862/is-rinoy
  • http://{BLOCKED}o.{BLOCKED}ctme.net:862/is-rinoy

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

12.724.06

FIRST VSAPI PATTERN DATE:

19 Aug 2016

VSAPI OPR PATTERN File:

12.725.00

VSAPI OPR PATTERN Date:

20 Aug 2016

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

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 Word
    • {default} = "{date installed}"
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • Microsoft Word = "wscript.exe //D "%Application Data%\Microsoft Office\Microsoft Word.WsF""
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Microsoft Word = "wscript.exe //D "%Application Data%\Microsoft Office\Microsoft Word.WsF""

Step 4

Reset Internet security settings

[ Learn More ]

Step 5

Scan your computer with your Trend Micro product to delete files detected as WORM_AUTORUN.SLRF. 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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