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WORM_MSIL.EAS

October 09, 2012
 Analysis by: kathleenno
 ALIASES:

Worm:Win32/Pushbot (Microsoft); Trojan.MSIL.Qhost.js (Kaspersky); Generic.dx!vjp (Mcafee); Mal/MSIL-BB (Sophos)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This malware sends messages that contain links to sites hosting remote copies of itself using certain Instant Messaging (IM) applications.

It opens a specific port to listen for remote malicious commands. It also connects to a URL in order to listen for these commands as well.

This worm 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:

87,552 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

13 May 2011

Payload:

Drops files, Creates files, Modifies system registry, Connects to URLs/IPs, Compromises system security

Arrival Details

This worm 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%\HEX-5823-6893-6818\jutched.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)

It creates the following folders:

  • %Application Data%\HEX-5823-6893-6818

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Java Update Manager = %Application Data%\HEX-5823-6893-6818\jutched.exe

Other System Modifications

This worm adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Application Data%\HEX-5823-6893-6818\jutched.exe = %Application Data%\HEX-5823-6893-6818\jutched.exe:*:Enabled:Java Update Manager

Propagation

This worm sends the following messages using the aforementioned Instant Messaging applications:

mira esta fotografa :D
seen this?? :D
This is the funniest photo ever!
olhar para esta foto :D
Wie findest du das Foto? :D
dette bildet :D
bekijk deze foto :D
poglej to fotografijo :D
pogledaj to slike :D
titta pa denna bild :D
pozrite sa na t to fotografiu :D
uita-te la aceasta fotografie :D
katso t kuvaa :D
bu resmi bakmak :D
spojrzec na to zdjecie :D
zd meg a k pet :D
ser p dette billede :D
vejte se na mou fotku :D
guardare quest'immagine :D
regardez cette photo :D

It sends messages that contain links to sites hosting remote copies of itself using the following instant-messaging (IM) applications:

  • Google Talk
  • ICQ
  • MSN Messenger
  • Paltalk
  • Skype
  • Xfire
  • Yahoo Messenger

Backdoor Routine

This worm opens the following port(s) where it listens for remote commands:

  • 1025

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • {BLOCKED}ution.nicaze.net

  SOLUTION

Minimum Scan Engine:

8.900

FIRST VSAPI PATTERN FILE:

8.154.15

FIRST VSAPI PATTERN DATE:

13 May 2011

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Identify and terminate files detected as WORM_MSIL.EAS

[ Learn More ]
  1. 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.
  2. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Java Update Manager = %Application Data%\HEX-5823-6893-6818\jutched.exe
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %Application Data%\HEX-5823-6893-6818\jutched.exe = %Application Data%\HEX-5823-6893-6818\jutched.exe:*:Enabled:Java Update Manager

Step 4

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.  %Application Data%\HEX-5823-6893-6818

Step 5

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