WORM_PALEVO.KC

 Analysis by: Karl Dominguez

 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Propagates via peer-to-peer networks, Propagates via removable drives, Propagates via instant messaging applications

This worm arrives via removable drives. It may be downloaded by other malware/grayware/spyware from remote sites. It may be unknowingly downloaded by a user while visiting malicious websites.

It adds registry entries to enable its automatic execution at every system startup.

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:

154,112 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

05 Nov 2010

Payload:

Launches DoS/DDoS attacks

Arrival Details

This worm arrives via removable drives.

It may be downloaded by other malware/grayware/spyware from remote sites.

It may be unknowingly downloaded by a user while visiting malicious websites.

Installation

This worm drops the following file(s)/component(s):

  • [Drive letter]:\LICNA\Desktop.ini

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

  • %User Profile%\csrss.exe

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

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:

HKEY_LOCAL_MACHINE\SOFTWARE\Mircosoft\
Windows NT\CurrentVersion\Winlogon
Taskman = %User Profile%\csrss.exe

Propagation

This worm creates the following folders in all removable drives:

  • [Drive letter]:\LICNA

It drops the following copy(ies) of itself in all removable drives:

  • [Drive letter]:\LICNA\PESMICA.EXE

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 codes}
shellexecute=LICNA\PESMICA.exe
{garbage codes}
shell\explore\command=LICNA\PESMICA.exe
{garbage codes}
open=LICNA\PESMICA.exe
{garbage codes}
@icon=fasfsa\jrtergregexe
{garbage codes}
action=Open folder to view files using Windows Explorer
{garbage codes}
USEAUTOPLAY=1
{garbage codes}
{garbage codes}
shell\open\command=LICNA\PESMICA.exe
{garbage codes}
Shell\open\command=LICNA\PESMICA.exe
{garbage codes}
icon=%SystemRoot%\system32\SHELL32.dll,4
{garbage codes}

NOTES:

Other Details

Based on analysis of the codes, it has the following capabilities:

  • It spreads via MSN Messenger and through the following P2P applications:
    • Ares
    • BearShare
    • DC++
    • eMule
    • iMesh
    • Kazaa
    • LimeWire
    • Shareaza
  • It is also capable of performing DoS attacks on affected systems using SYN flooding.

  SOLUTION

Minimum Scan Engine:

8.900

Step 1

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

Step 2

Identify and delete files detected as WORM_PALEVO.KC using either the Startup Disk or Recovery Console

[ 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.

HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Winlogon&&Taskman = %User Profile%\csrss.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.  [Drive Letter]:\LICNA

Step 5

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

[ Learn More ]
[autorun]
{garbage codes}
shellexecute=LICNA\PESMICA.exe
{garbage codes}
shell\explore\command=LICNA\PESMICA.exe
{garbage codes}
open=LICNA\PESMICA.exe
{garbage codes}
@icon=fasfsa\jrtergregexe
{garbage codes}
action=Open folder to view files using Windows Explorer
{garbage codes}
USEAUTOPLAY=1
{garbage codes}
{garbage codes}
shell\open\command=LICNA\PESMICA.exe
{garbage codes}
Shell\open\command=LICNA\PESMICA.exe
{garbage codes}
icon=%SystemRoot%\system32\SHELL32.dll,4
{garbage codes}

Step 6

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