WORM_LINEAGE.OI

 Analysis by: Roland Dela Paz

 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 removable drives


This worm 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:

116,290 bytes

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

17 Jul 2009

Payload:

Drops files

Installation

This worm drops the following files:

  • %System%\kavo.exe - copy of itself
  • %System%\kavo0.dll - detected as MAL_NSANTI-1
  • %User Temp%\5.dll - detected as MAL_NSANTI-1

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

It injects threads into the following normal process(es):

  • explorer.exe

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
kava = %System%\kavo.exe

Other System Modifications

This worm modifies the following registry entries to hide files with Hidden attributes:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = 2

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = 0

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SHOWALL
CheckedValue = 0

(Note: The default value data of the said registry entry is 1.)

Propagation

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

  • u.cmd

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 characters}
[AutoRun]
;{garbage characters}
open=u.cmd
;{garbage characters}
shell\open\Command=u.cmd
;{garbage characters}
shell\open\Default=1
;{garbage characters}
shell\explore\Command=u.cmd
;{garbage characters}

  SOLUTION

Minimum Scan Engine:

8.900

FIRST VSAPI PATTERN FILE:

5.150.05

FIRST VSAPI PATTERN DATE:

10 Mar 2008

VSAPI OPR PATTERN File:

5.151.00

VSAPI OPR PATTERN Date:

10 Mar 2010

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

Remove malware files dropped/downloaded by WORM_LINEAGE.OI

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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
    • kava = %System%\kavo.exe

Step 5

Restore this modified 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\Explorer\Advanced
    • From: Hidden = 2
      To: Hidden = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: ShowSuperHidden = 0
      To: ShowSuperHidden = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL
    • From: CheckedValue = 0
      To: CheckedValue = 1

Step 6

Search and delete AUTORUN.INF files created by WORM_LINEAGE.OI that contain these strings

[ Learn More ]
;{garbage characters}
[AutoRun]
;{garbage characters}
open=u.cmd
;{garbage characters}
shell\open\Command=u.cmd
;{garbage characters}
shell\open\Default=1
;{garbage characters}
shell\explore\Command=u.cmd
;{garbage characters}

Step 7

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