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TROJ_DROPPER.TQR

October 12, 2012
 ALIASES:

PWS:Win32/Zbot (Microsoft); PWS-Zbot (McAfee); Trojan.Zbot (Symantec); Trojan-Dropper.Win32.Injector.ajiq (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Generic.KD.481864 (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.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

196,096 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

23 Dec 2011

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:

  • %User Profile%\Application Data\Unwiy
  • %User Profile%\Application Data\Mioz

(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.)

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
{ED95C869-2538-D02F-8F88-9CE204D768AA} = ""%User Profile%\Unwiy\tulefuf.exe""

Other System Modifications

This Trojan deletes the following files:

  • %User Profile%\Cookies\administrator@google[2].txt
  • %User Profile%\Mioz\lociwyt.tmp

(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.)

It adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Hiokba

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Privacy

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Hiokba
Niow = {random values}

HKEY_CURRENT_USER\Software\Microsoft\
Internet Account Manager
Server ID = 4

HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4
FirstRun = 1

HKEY_CURRENT_USER\Identities
Last Username = "Main Identity"

HKEY_CURRENT_USER\Identities
Last User ID = "{341F68BA-C841-4200-A7B4-3D5CFF202166}"

HKEY_CURRENT_USER\Identities
Identity Login = 9853

HKEY_CURRENT_USER\Identities
Identity Ordinal = 2

HKEY_CURRENT_USER\Software\Microsoft\
Internet Account Manager\Accounts
ConnectionSettingsMigrated = 1

HKEY_CURRENT_USER\Identities\{341F68BA-C841-4200-A7B4-3D5CFF202166}\
Software\Microsoft\Outlook Express\
5.0
StoreMigratedV5 = 1

HKEY_CURRENT_USER\Identities\{341F68BA-C841-4200-A7B4-3D5CFF202166}\
Software\Microsoft\Outlook Express\
5.0
Settings Upgraded = 7

HKEY_CURRENT_USER\Identities\{341F68BA-C841-4200-A7B4-3D5CFF202166}\
Software\Microsoft\Outlook Express\
5.0
Running = 1

HKEY_CURRENT_USER\Software\Microsoft\
Internet Account Manager\Accounts
AssociatedID = {random values}

HKEY_CURRENT_USER\Software\Microsoft\
Hiokba
Rehaetu = {random values}

HKEY_CURRENT_USER\Software\Microsoft\
Hiokba
Poehiml = {random values}

Dropping Routine

This Trojan drops the following files:

  • %User Profile%\Application Data\887721875.log
  • %User Profile%\Unwiy\tulefuf.exe
  • %User Profile%\Mioz\lociwyt.yhs
  • %Application Data%\Identities\{341F68BA-C841-4200-A7B4-3D5CFF202166}\Microsoft\Outlook Express\Sent Items.dbx

(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.. %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.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}nawards.com/wp-content/themes/twentyten/config.php
  • http://www.{BLOCKED}e.com/webhp
  • http://{BLOCKED}eative.com/textpattern/tx.php
  • http://{BLOCKED}nawards.com/textpattern/tx.php

It deletes the initially executed copy of itself

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

Restart in Safe Mode

[ Learn More ]

Step 3

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_CURRENT_USER\Software\Microsoft
    • Hiokba
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer
    • Privacy

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
    • {ED95C869-2538-D02F-8F88-9CE204D768AA}=""%User Profile%\Unwiy\tulefuf.exe""
  • In HKEY_CURRENT_USER\Software\Microsoft\Hiokba
    • Niow={random values}
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Account Manager
    • Server ID=4
  • In HKEY_CURRENT_USER\Software\Microsoft\WAB\WAB4
    • FirstRun=1
  • In HKEY_CURRENT_USER\Identities
    • Last Username="Main Identity"
  • In HKEY_CURRENT_USER\Identities
    • Last User ID="{341F68BA-C841-4200-A7B4-3D5CFF202166}"
  • In HKEY_CURRENT_USER\Identities
    • Identity Login=9853
  • In HKEY_CURRENT_USER\Identities
    • Identity Ordinal=2
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Account Manager\Accounts
    • ConnectionSettingsMigrated=1
  • In HKEY_CURRENT_USER\Identities\{341F68BA-C841-4200-A7B4-3D5CFF202166}\Software\Microsoft\Outlook Express\5.0
    • StoreMigratedV5=1
  • In HKEY_CURRENT_USER\Identities\{341F68BA-C841-4200-A7B4-3D5CFF202166}\Software\Microsoft\Outlook Express\5.0
    • Settings Upgraded=7
  • In HKEY_CURRENT_USER\Identities\{341F68BA-C841-4200-A7B4-3D5CFF202166}\Software\Microsoft\Outlook Express\5.0
    • Running=1
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Account Manager\Accounts
    • AssociatedID={random values}
  • In HKEY_CURRENT_USER\Software\Microsoft\Hiokba
    • Rehaetu={random values}
  • In HKEY_CURRENT_USER\Software\Microsoft\Hiokba
    • Poehiml={random values}

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.
  • %User Profile%\Application Data\Unwiy
  • %User Profile%\Application Data\Mioz

Step 6

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.
  • %User Profile%\Application Data\887721875.log
  • %User Profile%\Unwiy\tulefuf.exe
  • %User Profile%\Mioz\lociwyt.yhs
  • %Application Data%\Identities\{341F68BA-C841-4200-A7B4-3D5CFF202166}\Microsoft\Outlook Express\Sent Items.dbx

Step 7

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

Step 8

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %User Profile%\Cookies\administrator@google[2].txt
  • %User Profile%\Mioz\lociwyt.tmp


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