Analysis by: JocelynR

 PLATFORM:

Windows 98, ME, NT, 2000, XP, Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Trend Micro has flagged this Trojan as noteworthy due to the multiple samples of this malware received from multiple, independent sources, including customer reports and internal sources. This indicates that this malware poses a high risk to users due to the increased possibility of infection.

This worm may be dropped by other malware.

It drops copies of itself in all removable drives. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

  TECHNICAL DETAILS

File Size: 35,328 bytes
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 27 Apr 2010

Arrival Details

This worm may be dropped by the following malware:

  • VBS_EMOTI.A

Installation

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

  • %Program Files%\Microsoft Common\svchost.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

It drops the following file(s)/component(s):

  • %User Temp%\{random name}.tmp

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

It creates the following folders:

  • %Program Files%\Microsoft Common

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
explorer.exe
Debugger = "%Program Files%\Microsoft Common\svchost.exe"

Propagation

This worm drops copies of itself in all removable drives.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

Other Details

This worm connects to the following possibly malicious URL:

  • http://{BLOCKED}ason.com/lde/ld.php

  SOLUTION

Minimum Scan Engine: 8.900
VSAPI OPR PATTERN File: 7.130.14
VSAPI OPR PATTERN Date: 28 Apr 2010

Step 1

Remove malware files dropped/downloaded by WORM_EMOTI.A

    • VBS_EMOTI.A 
    • RTKT_EMOTI.A

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\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\
    • explorer.exe

Step 4

Search and delete AUTORUN.INF files created by WORM_EMOTI.A that contain these strings

[ Learn More ]
 [autoun]
;a
open=system.exe
;a
shellexecute=system.exe
;a
shell\Explore\command=system.exe
;a
shell\Open\command=system.exe
;a
shell=Explore

Step 5

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


*Note: 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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