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WORM_PALEVO.AP

May 23, 2013
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Propagates via peer-to-peer networks

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

It connects to certain URLs. It may do this to remotely inform a malicious user of its installation. It may also do this to download possibly malicious files onto the computer, which puts the computer at a greater risk of infection by other threats.

  TECHNICAL DETAILS

File Size:

94,208 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

13 Oct 2010

Payload:

Connects to URLs/Ips

Arrival Details

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

  • C:\\RECYCLER\\{CLSID}\\syscr.exe

It injects itself into the following processes running in the affected system's memory:

  • EXPLORER.EXE

Autostart Technique

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

HKLM\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Taskman = C:\RECYCLER\{CLSID}\syscr.exe

Propagation

This worm drops copies of itself into the following folders used in peer-to-peer (P2P) networks:

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

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]
open=RECYCLER\autorun.exe
icon=%SystemRoot%\system32\SHELL32.dll,4
action=Open folder to view files
shell\open=Open
shell\open\command=RECYCLER\autorun.exe
shell\open\default=1

Download Routine

This worm connects to the following malicious URLs:

  • {BLOCKED}lerequests.com

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI PATTERN File:

7.536.12

VSAPI PATTERN Date:

13 Oct 2010

VSAPI PATTERN Date:

10/13/2010 12:00:00 AM

Step 1

Scan your computer with your Trend Micro product and note files detected as WORM_PALEVO.AP

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 HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • Taskman=C:\RECYCLER\{CLSID}\syscr.exe

Step 4

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

[ Learn More ]
[autorun]
open=RECYCLER\autorun.exe
icon=%SystemRoot%\system32\SHELL32.dll,4
action=Open folder to view files
shell\open=Open
shell\open\command=RECYCLER\autorun.exe
shell\open\default=1

Step 5

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