WORM_PALEVO.ZQWA

October 08, 2012
 Analysis by: Roland Marco Dela Paz
 ALIASES:

Sophos: Mal/Palevo-A

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This worm 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 a website to send and receive information.

  TECHNICAL DETAILS

File Size:

109,056 bytes

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

10 Mar 2011

Installation

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

  • %Application Data%\rljlz.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 injects codes into the following process(es):

  • explrorer.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 = "%Application Data%\rljlz.exe"

Propagation

This worm creates the following folders in all removable drives:

  • [DRIVE]:\OBJESI

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

  • [DRIVE]:\OBJESI\sise.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:

;{garbage codes}
[autorun]
shell\Install\command=OBJESI\sise.exe
shell\open\command=OBJESI\sise.exe
shell\explore\command=OBJESI\sise.exe
Shell\open\command=OBJESI\sise.exe
useautoplay=1
shellexecute=OBJESI\sise.exe
open=OBJESI\sise.exe
action=Open folder to view files
icon=shell32.dll,4

Backdoor Routine

This worm connects to the following websites to send and receive information:

  • {BLOCKED}.{BLOCKED}.227.248

  SOLUTION

Minimum Scan Engine:

8.900

SSAPI PATTERN File:

*under processing

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

Since this malware uses rootkit technology, detection and removal using normal and safe mode methods may not eliminate it completely. This procedure restarts the system using the Windows Recovery Console.

  1. Insert the Windows Installation CD into the CD drive, then Press the restart button.
  2. Upon prompt, press any key to boot from the CD.
  3. On the main menu, type r to go to the Recovery Console.
  4. Type the drive that contains Windows (usually C:) and press Enter.
  5. In the input box, type the following then press Enter:
DATA_GENERIC
  • Type exit and press Enter to restart the system normally.

    • 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 = %Application Data%\rljlz.exe

    Step 4

    Search and delete these files

    [ Learn More ]
    There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
    • [DRIVE]:\OBJESI

    Step 5

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

    [ Learn More ]
    ;{garbage codes}
    [autorun]
    shell\Install\command=OBJESI\sise.exe
    shell\open\command=OBJESI\sise.exe
    shell\explore\command=OBJESI\sise.exe
    Shell\open\command=OBJESI\sise.exe
    useautoplay=1
    shellexecute=OBJESI\sise.exe
    open=OBJESI\sise.exe
    action=Open folder to view files
    icon=shell32.dll,4

    Step 6

    Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_PALEVO.ZQWA. 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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