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WORM_KOLAB.CU

October 09, 2012
 Analysis by: MarfelTi
 ALIASES:

Microsoft: VirTool:Win32/VBInject.gen!BJ ; Kaspersky: Net-Worm.Win32.Kolab.bde

 PLATFORM:

Windows 2000, Windows XP, Wimdows 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 arrives by connecting affected removable drives to a system. 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 propagates via shared networks and drops copies of itself into available networks.

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:

470,592 bytes

File Type:

EXE

Memory Resident:

Yes

Arrival Details

This worm arrives by connecting affected removable drives to a system.

It may arrive via network shares.

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 files:

  • %System%\ap
  • %System%\sv.exe
  • %System%\vbzip10.dll

(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.)

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

  • %System%\Install.exe
  • %System%\sms.exe

(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.)

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
sms = "%System%\sms.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WIndows\CurrentVersion\Run
sms = "%System%\sms.exe"

File Infection

This worm propagates via shared networks and drops copies of itself into available networks.

Propagation

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

  • Install.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]
open=install.exe
icon=%SystemRoot%\system32\SHELL32.dll,7
UseAutoPlay=1
action=@install.exe
shell\open=Abrir
shell\open\command=install.exe
shell\open\Default=1

  SOLUTION

Minimum Scan Engine:

8.900

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

Scan your computer with your Trend Micro product and note files detected as WORM_KOLAB.CU

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
    • sms = "%System%\sms.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WIndows\CurrentVersion\Run
    • sms = "%System%\sms.exe"

Step 5

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.
  • %System%\ap
  • %System%\sv.exe
  • %System%\vbzip10.dll

Step 6

Search and delete AUTORUN.INF files created by WORM_KOLAB.CU that contain these strings

[ Learn More ]

[AUTORUN]
open=install.exe
icon=%SystemRoot%\system32\SHELL32.dll,7
UseAutoPlay=1
action=@install.exe
shell\open=Abrir
shell\open\command=install.exe
shell\open\Default=1

Step 7

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