Analysis by: Anthony Joe Melgarejo

ALIASES:

Trojan.Dropper (Symantec)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 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: 6,128,128 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 22 Jan 2013

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:

  • %Desktop%\Free PDF Unlocker.lnk
  • %Start Menu%\Programs\Free PDF Unlocker\Free PDF Unlocker.lnk
  • %Start Menu%\Programs\Free PDF Unlocker\Uninstall Free PDF Unlocker.lnk
  • %Application Data%\MCommon\config.dat
  • %Application Data%\MCommon\sites.dat
  • %Application Data%\MCommon\uid.dat
  • %Application Data%\MCommon\uinfo.dat
  • %Application Data%\MCommon\vinfo.dat
  • %Application Data%\MCommon\WindowsLiveUpdate.exe
  • %Application Data%\WinLive\Interop.SHDocVw.dll
  • %Application Data%\WinLive\MSHTMLSubset.dll
  • %Application Data%\WinLive\WinLive.dll
  • %Application Data%\Mozilla\Firefox\Extensions
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome\content
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome\content\addlist.js
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome\content\em.xul
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome\content\hashtable.js
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome\content\overlay.xul
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome\content\update.js
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome\skin
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome\skin\mozilla-logo.png
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome.manifest
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\install.rdf
  • %User Temp%\MTemp\chrome
  • %User Temp%\MTemp\chrome\content
  • %User Temp%\MTemp\chrome\content\addlist.js
  • %User Temp%\MTemp\chrome\content\em.xul
  • %User Temp%\MTemp\chrome\content\hashtable.js
  • %User Temp%\MTemp\chrome\content\overlay.xul
  • %User Temp%\MTemp\chrome\content\update.js
  • %User Temp%\MTemp\chrome\skin
  • %User Temp%\MTemp\chrome\skin\mozilla-logo.png
  • %User Temp%\MTemp\chrome.manifest
  • %User Temp%\MTemp\install.rdf
  • %Program Files%\Free PDF Unlocker\AxInterop.XtremeCommandBars.dll
  • %Program Files%\Free PDF Unlocker\AxInterop.XtremeSkinFramework.dll
  • %Program Files%\Free PDF Unlocker\Codejock.CommandBars.v12.1.1.lic
  • %Program Files%\Free PDF Unlocker\Codejock.CommandBars.v12.1.1.ocx
  • %Program Files%\Free PDF Unlocker\Codejock.SkinFramework.v12.1.1.lic
  • %Program Files%\Free PDF Unlocker\Codejock.SkinFramework.v12.1.1.ocx
  • %Program Files%\Free PDF Unlocker\Dictionary.txt
  • %Program Files%\Free PDF Unlocker\dotnetfx35setup.exe
  • %Program Files%\Free PDF Unlocker\Free PDF Unlocker.application
  • %Program Files%\Free PDF Unlocker\Free PDF Unlocker.exe.config
  • %Program Files%\Free PDF Unlocker\Free PDF Unlocker.exe.manifest
  • %Program Files%\Free PDF Unlocker\Interop.XtremeCommandBars.dll
  • %Program Files%\Free PDF Unlocker\Interop.XtremeSkinFramework.dll
  • %Program Files%\Free PDF Unlocker\itextsharp.dll
  • %Program Files%\Free PDF Unlocker\styles
  • %Program Files%\Free PDF Unlocker\styles\Office2007Silver.dll
  • %Program Files%\Free PDF Unlocker\styles\Vista.cjstyles
  • %Program Files%\Free PDF Unlocker\unins000.dat
  • %Program Files%\Free PDF Unlocker\unins000.exe

(Note: %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Desktop on Windows Vista and 7.. %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu on Windows Vista and 7.. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.. %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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

It drops and executes the following files:

  • %Program Files%\Free PDF Unlocker\Free PDF Unlocker.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

It creates the following folders:

  • %Start Menu%\Programs\Free PDF Unlocker
  • %Application Data%\MCommon
  • %Application Data%\WinLive
  • %User Temp%\MTemp
  • %Program Files%\Free PDF Unlocker

(Note: %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu on Windows Vista and 7.. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.. %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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

Autostart Technique

This Trojan adds the following registry keys to install itself as a Browser Helper Object (BHO):

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects\{2adefb8e-b923-35e6-86e2-2b7841f5d2a2}

It creates the following registry entries to enable automatic execution of dropped component at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
WindowsLiveUpdate = "%Application Data%\MCommon\WindowsLiveUpdate.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CLASSES_ROOT\IE.PerformancePack

HKEY_CLASSES_ROOT\Component Categories\{62C8FE65-4EBB-45e7-B440-6E39B2CDBF29}

HKEY_CURRENT_USER\Software\Free PDF Unlocker

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Ext\
Stats\{2ADEFB8E-B923-35E6-86E2-2B7841F5D2A2}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\BAP

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\PPP

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\RASBACP

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\RASCCP

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\RASEAP

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\RASIPCP

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\RASIPHLP

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\RASMAN

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\RASPAP

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\RASQEC

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\RASSPAP

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\RASTAPI

HKEY_CLASSES_ROOT\IE.PerformancePack\CLSID

HKEY_CLASSES_ROOT\CLSID\{2ADEFB8E-B923-35E6-86E2-2B7841F5D2A2}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{2ADEFB8E-B923-35E6-86E2-2B7841F5D2A2}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Free PDF Unlocker_is1

It adds the following registry entries:

HKEY_CLASSES_ROOT\Component Categories\{62C8FE65-4EBB-45e7-B440-6E39B2CDBF29}
0 = ".NET Category"

HKEY_CURRENT_USER\Software\Mozilla\
Firefox\Extensions
hotfix@mozilla.org = "%Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Approved Extensions
{2ADEFB8E-B923-35e6-86E2-2B7841F5D2A2} = "{random values}"

HKEY_LOCAL_MACHINE\SOFTWARE\Mozilla\
Firefox\Extensions
hotfix@mozilla.org = "%Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\
0002
EnableForRas = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\
0002
EnableForRouting = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\
0002
EnableForOutboundRouting = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\
0003
EnableForRas = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\
0003
EnableForRouting = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\
0003
EnableForOutboundRouting = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\
0004
EnableForRas = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\
0004
EnableForRouting = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\
0004
EnableForOutboundRouting = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\
0005
EnableForRas = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\
0005
EnableForRouting = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\
0005
EnableForOutboundRouting = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{2ADEFB8E-B923-35E6-86E2-2B7841F5D2A2}
(Default) = "Blog This in Windows Live"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\RasMan\Parameters
IpOutLowWatermark = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\RasMan\Parameters
IpOutHighWatermark = "5"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\RasMan\Parameters
NbfOutLowWatermark = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\RasMan\Parameters
NbfOutHighWatermark = "5"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\RasMan\Parameters
NbfInLowWatermark = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\RasMan\Parameters
NbfInHighWatermark = "5"

HKEY_CLASSES_ROOT\IE.PerformancePack
(Default) = "IE.PerformancePack"

HKEY_CLASSES_ROOT\IE.PerformancePack\CLSID
(Default) = "{2ADEFB8E-B923-35E6-86E2-2B7841F5D2A2}"

HKEY_CLASSES_ROOT\CLSID\{2ADEFB8E-B923-35E6-86E2-2B7841F5D2A2}
(Default) = "Blog This in Windows Live"

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 9.674.02
FIRST VSAPI PATTERN DATE: 22 Jan 2013
VSAPI OPR PATTERN File: 9.675.00
VSAPI OPR PATTERN Date: 23 Jan 2013

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Terminate a malware/grayware process

[ Learn More ]

*Note: If the detected process is not displayed in theWindows Task Manager, continue doing the next steps.

    • Free PDF Unlocker.exe

Step 3

Remove TROJ_DROPPR.BECI by using its own Uninstall option

[ Learn More ]
To uninstall the grayware process

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\RunOnce
    • WindowsLiveUpdate = "%Application Data%\MCommon\WindowsLiveUpdate.exe"
  • In HKEY_CLASSES_ROOT\Component Categories\{62C8FE65-4EBB-45e7-B440-6E39B2CDBF29}
    • 0 = ".NET Category"
  • In HKEY_CURRENT_USER\Software\Mozilla\Firefox\Extensions
    • hotfix@mozilla.org = "%Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Approved Extensions
    • {2ADEFB8E-B923-35e6-86E2-2B7841F5D2A2} = "{random values}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Mozilla\Firefox\Extensions
    • hotfix@mozilla.org = "%Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\0002
    • EnableForRas = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\0002
    • EnableForRouting = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\0002
    • EnableForOutboundRouting = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\0003
    • EnableForRas = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\0003
    • EnableForRouting = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\0003
    • EnableForOutboundRouting = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\0004
    • EnableForRas = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\0004
    • EnableForRouting = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\0004
    • EnableForOutboundRouting = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\0005
    • EnableForRas = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\0005
    • EnableForRouting = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\0005
    • EnableForOutboundRouting = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RasMan\Parameters
    • IpOutLowWatermark = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RasMan\Parameters
    • IpOutHighWatermark = "5"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RasMan\Parameters
    • NbfOutLowWatermark = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RasMan\Parameters
    • NbfOutHighWatermark = "5"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RasMan\Parameters
    • NbfInLowWatermark = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RasMan\Parameters
    • NbfInHighWatermark = "5"

Step 5

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\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects
    • {2adefb8e-b923-35e6-86e2-2b7841f5d2a2}
  • In HKEY_CLASSES_ROOT
    • IE.PerformancePack
  • In HKEY_CLASSES_ROOT\Component Categories
    • {62C8FE65-4EBB-45e7-B440-6E39B2CDBF29}
  • In HKEY_CURRENT_USER\Software
    • Free PDF Unlocker
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Ext\Stats
    • {2ADEFB8E-B923-35E6-86E2-2B7841F5D2A2}
  • In HKEY_CLASSES_ROOT\CLSID
    • {2ADEFB8E-B923-35E6-86E2-2B7841F5D2A2}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID
    • {2ADEFB8E-B923-35E6-86E2-2B7841F5D2A2}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing
    • BAP
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing
    • PPP
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing
    • RASBACP
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing
    • RASCCP
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing
    • RASEAP
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing
    • RASIPCP
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing
    • RASIPHLP
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing
    • RASMAN
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing
    • RASPAP
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing
    • RASQEC
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing
    • RASSPAP
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing
    • RASTAPI

Step 6

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.
  • %Application Data%\MCommon
  • %Application Data%\WinLive
  • %User Temp%\MTemp

Step 7

Scan your computer with your Trend Micro product to delete files detected as TROJ_DROPPR.BECI. 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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