ALIASES:

TrojanDownloader:Win32/Tearspear (Microsoft); Downloader.a!za (McAfee); Downloader (Symantec); PAK:UPX, Trojan-Downloader.Win32.Genome.cvwn (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Crypt.Delf.AH (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • 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.

  TECHNICAL DETAILS

File Size: 262,656 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 01 Jun 2012

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 creates the following folders:

  • %Start Menu%\Programs\F0BDFF951
  • %User Profile%\APPLIC~1\drivers
  • %User Profile%\APPLIC~1\windows
  • %User Profile%\Application Data\drivers
  • %User Profile%\Application Data\windows

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

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\Software\Description\
Microsoft\Rpc\UuidTemporaryData

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
MSSQLServer\Client\SuperSocketNetLib\
LastConnect

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Description\
Microsoft\Rpc\UuidTemporaryData
NetworkAddress = "{random values}"

HKEY_LOCAL_MACHINE\SOFTWARE\Description\
Microsoft\Rpc\UuidTemporaryData
NetworkAddressLocal = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
MSSQLServer\Client\SuperSocketNetLib\
LastConnect
pato0006.db.7172224.hostedresource.com = "{random characters}"

HKEY_CURRENT_USER\Software\Microsoft\
Command Processor
99 = "4"

HKEY_CURRENT_USER\Software\Microsoft\
Command Processor
01 = "7"

HKEY_CURRENT_USER\Software\Microsoft\
Command Processor
02 = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Command Processor
03 = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Command Processor
04 = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Command Processor
05 = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Command Processor
06 = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Command Processor
08 = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Command Processor
09 = "7"

HKEY_CURRENT_USER\Software\Microsoft\
Command Processor
07 = "7"

Dropping Routine

This Trojan drops the following files:

  • %Start Menu%\Programs\F0BDFF951\conhots.exe
  • %User Startup%\conhots.LNK
  • %Start Menu%\Programs\F0BDFF951\chots.exe
  • %User Startup%\chots.LNK
  • %Start Menu%\Programs\F0BDFF951\cssrss.exe
  • %Start Menu%\Programs\F0BDFF951\ONLINE.dll
  • %Start Menu%\Programs\F0BDFF951\data.dll
  • %Start Menu%\Programs\F0BDFF951\F0BDFF95 (5) BRIAN-243CEDCDD
  • %User Profile%\drivers\rtl8194.vxd
  • %User Profile%\drivers\rtl9976.vxd
  • %User Profile%\drivers\rtl745G.vxd
  • %User Profile%\drivers\rtl3264.vxd
  • %User Profile%\drivers\rtl6432.vxd
  • %User Profile%\windows\energy.exe
  • %User Startup%\2F0BDFF952.LNK
  • %User Profile%\drivers\rtl2119.vxd
  • %User Profile%\drivers\ctrl2580.vxd5

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

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://kadore-ddo.{BLOCKED}m.br/images/aviso/aviso.php
  • http://www.{BLOCKED}e.com/index.html
  • http://{BLOCKED}213.200/23/readme.txt

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.200

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

Delete this registry key

[ 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\Description\Microsoft\Rpc
    • UuidTemporaryData
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSSQLServer\Client\SuperSocketNetLib
    • LastConnect

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\Description\Microsoft\Rpc\UuidTemporaryData
    • NetworkAddress = "{random values}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Description\Microsoft\Rpc\UuidTemporaryData
    • NetworkAddressLocal = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSSQLServer\Client\SuperSocketNetLib\LastConnect
    • pato0006.db.7172224.hostedresource.com = "{random characters}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Command Processor
    • 99 = "4"
  • In HKEY_CURRENT_USER\Software\Microsoft\Command Processor
    • 01 = "7"
  • In HKEY_CURRENT_USER\Software\Microsoft\Command Processor
    • 02 = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Command Processor
    • 03 = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Command Processor
    • 04 = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Command Processor
    • 05 = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Command Processor
    • 06 = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Command Processor
    • 08 = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Command Processor
    • 09 = "7"
  • In HKEY_CURRENT_USER\Software\Microsoft\Command Processor
    • 07 = "7"

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.
  • %Start Menu%\Programs\F0BDFF951\conhots.exe
  • %User Startup%\conhots.LNK
  • %Start Menu%\Programs\F0BDFF951\chots.exe
  • %User Startup%\chots.LNK
  • %Start Menu%\Programs\F0BDFF951\cssrss.exe
  • %Start Menu%\Programs\F0BDFF951\ONLINE.dll
  • %Start Menu%\Programs\F0BDFF951\data.dll
  • %Start Menu%\Programs\F0BDFF951\F0BDFF95 (5) BRIAN-243CEDCDD
  • %User Profile%\drivers\rtl8194.vxd
  • %User Profile%\drivers\rtl9976.vxd
  • %User Profile%\drivers\rtl745G.vxd
  • %User Profile%\drivers\rtl3264.vxd
  • %User Profile%\drivers\rtl6432.vxd
  • %User Profile%\windows\energy.exe
  • %User Startup%\2F0BDFF952.LNK
  • %User Profile%\drivers\rtl2119.vxd
  • %User Profile%\drivers\ctrl2580.vxd5

Step 5

Search and delete these folders

[ 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.
  • %Start Menu%\Programs\F0BDFF951
  • %User Profile%\APPLIC~1\drivers
  • %User Profile%\APPLIC~1\windows
  • %User Profile%\Application Data\drivers
  • %User Profile%\Application Data\windows

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_DLOADER.AQO. 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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