WORM_PALEVO.SMEJ

 Analysis by: kathleenno

 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

Infection Channel:

Propagates via removable drives


This worm arrives via peer-to-peer (P2P) shares. It arrives via removable drives. 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 drives. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

It opens a random port to allow a remote user to connect to the affected system. Once a successful connection is established, the remote user executes commands on the affected system. It runs certain commands that it receives remotely from a malicious user. Doing this puts the affected computer and information found on the computer at greater risk. It connects to a website to send and receive information.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

20 Jun 2011

Payload:

Compromises system security

Arrival Details

This worm arrives via peer-to-peer (P2P) shares.

It arrives via removable drives.

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 adds the following folders:

  • %System Root%\RECYCLER\{SID}

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

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

  • %System Root%\RECYCLER\{SID}\hod.exe

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It drops the following non-malicious file:

  • %System Root%\RECYCLER\{SID}\Desktop.ini

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It injects itself into the following processes as part of its memory residency routine:

  • explorer.exe

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\Winlogon
Taskman = "%System Root%\RECYCLER\{SID}\hod.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.

The said .INF file contains the following strings:

{AutoRun}
;{garbage characters}
[autORUN]
;open=setup.exe
;icon=setup.exe,0
shelLexEcute=.\RECYCLER\SEtUp.exe
icon=%wIndIr%\sYstEm32\ShElL32.DlL,4
action=Open folder to view files
;shell\op en ;shell\opeN ;shell\openn
Shell\Open\Command=REcYCLER\\\\\\SEtUp.exe
;shell\ex p lor ;\sshell\ploreX
Shell\eXpLorE\Command=RECyCLER\\\SEtUp.exe
useautoplay=1
[Comment]
brand=suck

Backdoor Routine

This worm opens a random port to allow a remote user to connect to the affected system. Once a successful connection is established, the remote user executes commands on the affected system.

It executes the following command(s) from a remote malicious user:

  • launch TCP and UDP flood
  • propagate itself via peer-to-peer networks
  • propagate itself via removable drives
  • propagate via MSN messenger by sending messages containing a link where a copy of itself may be downloaded
  • retrieve Firefox and Internet Explorer passwords

It connects to the following websites to send and receive information:

  • {BLOCKED}h1Z.slindrio.com
  • {BLOCKED}0per.nertina.com
  • {BLOCKED}37.anjlia.com

NOTES:

It may also arrive as a downloaded file from links sent via messages in MSN messenger.

It may also arrive via the following P2P networks:

  • Ares
  • BearShare
  • DC++
  • eMule
  • iMesh
  • Kazaa
  • Limewire
  • Shareaza

  SOLUTION

Minimum Scan Engine:

8.900

FIRST VSAPI PATTERN FILE:

8.237.00

FIRST VSAPI PATTERN DATE:

20 Jun 2011

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 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\Windows NT\CurrentVersion\Winlogon
    • Taskman = "%System Root%\RECYCLER\{SID}\hod.exe"

Step 4

Search and delete this folder

[ 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.
  • %System Root%\RECYCLER\{SID}

Step 5

Search and delete AUTORUN.INF files created by WORM_PALEVO.SMEJ that contain these strings

[ Learn More ]
 {AutoRun}
;{garbage characters}
[autORUN]
;open=setup.exe
;icon=setup.exe,0
shelLexEcute=.\RECYCLER\SEtUp.exe
icon=%wIndIr%\sYstEm32\ShElL32.DlL,4
action=Open folder to view files
;shell\op en ;shell\opeN ;shell\openn
Shell\Open\Command=REcYCLER\\\\\\SEtUp.exe
;shell\ex p lor ;\sshell\ploreX
Shell\eXpLorE\Command=RECyCLER\\\SEtUp.exe
useautoplay=1
[Comment]
brand=suck

Step 6

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