TROJ_CUTWAIL.BU

October 09, 2012
 Analysis by: Cris Nowell Pantanilla
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

92,672 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

29 Oct 2010

Arrival Details

This Trojan 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 Trojan drops the following files:

  • %System%\drivers\wcscd.sys - TROJ_AGENT.SMC1

(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:

  • %User Profile%\wuaucldt.exe
  • %System%\wuaucldt.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.. %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 injects threads into the following normal process(es):

  • svchost.exe

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
wuaucldt = %User Profile%\wuaucldt.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
wuaucldt = %System%\wuaucldt.exe

Other Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}5.{BLOCKED}4.239.87.{BLOCKED}dr.arpa
  • {BLOCKED}3.{BLOCKED}m.com.ua
  • {BLOCKED}8.{BLOCKED}0.80.34.{BLOCKED}servers.com
  • {BLOCKED}8.{BLOCKED}0.80.35
  • {BLOCKED}8.{BLOCKED}0.80.36
  • {BLOCKED}3.{BLOCKED}0.36.70.{BLOCKED}dr.arpa
  • 3.{BLOCKED}0.74.65.{BLOCKED}dr.arpa
  • 3.{BLOCKED}0.74.65.{BLOCKED}ic.{BLOCKED}esdata.net
  • {BLOCKED}9.{BLOCKED}8.{BLOCKED}1.212.{BLOCKED}dr.arpa
  • {BLOCKED}0.{BLOCKED}6.100.242
  • {BLOCKED}0.{BLOCKED}6.100.243
  • {BLOCKED}0.{BLOCKED}6.100.244
  • {BLOCKED}4.{BLOCKED}2.4.12
  • {BLOCKED}4.{BLOCKED}2.4.13
  • {BLOCKED}records.com.br
  • {BLOCKED}8.iptp.net
  • {BLOCKED}tal.com
  • {BLOCKED}el.{BLOCKED}ngquest.com
  • {BLOCKED}xrecords.com.br
  • {BLOCKED}k.{BLOCKED}hantom.com
  • {BLOCKED}ash.com
  • {BLOCKED}tion.{BLOCKED}er.com.br
  • {BLOCKED}3.{BLOCKED}t2.com.br
  • {BLOCKED}05.{BLOCKED}re.ne.jp
  • {BLOCKED}ng.{BLOCKED}rg.com.ua
  • {BLOCKED}r.{BLOCKED}hima-u.ac.jp
  • {BLOCKED}2.{BLOCKED}p.km.ua
  • {BLOCKED}ja.{BLOCKED}ay.com.br
  • {BLOCKED}mba.{BLOCKED}da.com.ua
  • {BLOCKED}rkey.com.ua
  • {BLOCKED}1.{BLOCKED}pamer.com
  • {BLOCKED}2.{BLOCKED}pamer.com
  • {BLOCKED}s.org.ua
  • {BLOCKED}oprint.com
  • {BLOCKED}v.{BLOCKED}ndd.jp
  • {BLOCKED}dor165.{BLOCKED}ting.com.br
  • {BLOCKED}l.{BLOCKED}kro.ua
  • {BLOCKED}76.{BLOCKED}eb.com.br
  • {BLOCKED}ic.{BLOCKED}1.20.35.41.{BLOCKED}nter1.com.br
  • {BLOCKED}ic.{BLOCKED}1.20.45.207.{BLOCKED}enter1.com.br
  • {BLOCKED}w1.{BLOCKED}t2.com.br
  • {BLOCKED}rvers.net
  • www.{BLOCKED}dd.jp
  • www.{BLOCKED}oxrecords.com.br
  • www.{BLOCKED}er.com.br
  • www.{BLOCKED}eshop.com.br
  • www.{BLOCKED}folheados.com.br
  • www.{BLOCKED}gistics.co.jp
  • www.{BLOCKED}uryislandcasino.com.ua

However, as of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine:

8.900

FIRST VSAPI PATTERN FILE:

7.576.49

FIRST VSAPI PATTERN DATE:

29 Oct 2010

Step 1

Restart in Safe Mode

[ Learn More ]

Step 2

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
    • wuaucldt="%User Profile%\wuaucldt.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • wuaucldt="%System%\wuaucldt.exe"

Step 3

Search and delete this file

[ 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%\drivers\wcscd.sys

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_CUTWAIL.BU. 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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