ALIASES:

TrojanDownloader:Win32/Renos.AS (Microsoft); Downloader-ASH.gen.b (McAfee); Trojan.Blusod (Symantec); Backdoor.Win32.Frauder.fb (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Win32/Cryptor (AVG)

 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: 199,168 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 17 Jun 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.

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
lphc3u8j0eral = "%System%\lphc3u8j0eral.exe"

Other System Modifications

This Trojan deletes the following files:

  • %System%\lphc3u8j0eral.exe:Zone.Identifier
  • %User Temp%\.tt6.tmp
  • %User Temp%\.tt9.tmp
  • %User Temp%\.ttC.tmp
  • %User Temp%\.ttF.tmp
  • %User Temp%\.tt12.tmp

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.. %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.)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Software Notifier

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System

HKEY_CURRENT_USER\Software\Sysinternals

HKEY_CURRENT_USER\Software\Sysinternals\
Bluescreen Screen Saver

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Software Notifier
InstallID = "e3e26843-77bf-4cb6-ba4f-888a754b7af9"

HKEY_CURRENT_USER\Control Panel\Desktop
ConvertedWallpaper = "%System%\phc3u8j0eral.bmp"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
NoDispBackgroundPage = "1"

HKEY_CURRENT_USER\Software\Sysinternals\
Bluescreen Screen Saver
EulaAccepted = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
NoDispScrSavPage = "1"

It modifies the following registry entries:

HKEY_CURRENT_USER\Control Panel\Colors
Background = "0 0 255"

(Note: The default value data of the said registry entry is 0 78 152.)

HKEY_CURRENT_USER\Control Panel\Desktop
WallpaperStyle = "0"

(Note: The default value data of the said registry entry is 2.)

HKEY_CURRENT_USER\Control Panel\Desktop
TileWallpaper = "0"

(Note: The default value data of the said registry entry is 0.)

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = "%System%\phc3u8j0eral.bmp"

(Note: The default value data of the said registry entry is %Windows%\web\wallpaper\Bliss.bmp.)

HKEY_CURRENT_USER\Control Panel\Desktop
OriginalWallpaper = "%System%\phc3u8j0eral.bmp"

HKEY_CURRENT_USER\Control Panel\Desktop
SCRNSAVE.EXE = "%System%\blphc3u8j0eral.scr"

(Note: The default value data of the said registry entry is %Windows%\system32\logon.scr.)

HKEY_CURRENT_USER\Control Panel\Desktop
ScreenSaveActive = "1"

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Control Panel\Desktop
ScreenSaveTimeOut = "600"

(Note: The default value data of the said registry entry is 600.)

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\.tt1.tmp.vbs
  • %System%\phc3u8j0eral.bmp
  • %System%\blphc3u8j0eral.scr

(Note: %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.. %System% is the Windows system folder, which is usually C:\Windows\System32.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://windowsupdate.{BLOCKED}oft.com
  • http://{BLOCKED}8.com/{random path}

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.300

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

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_LOCAL_MACHINE\SOFTWARE\Microsoft
    • Software Notifier
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies
    • System
  • In HKEY_CURRENT_USER\Software
    • Sysinternals
  • In HKEY_CURRENT_USER\Software\Sysinternals
    • Bluescreen Screen Saver

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • lphc3u8j0eral = "%System%\lphc3u8j0eral.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Software Notifier
    • InstallID = "e3e26843-77bf-4cb6-ba4f-888a754b7af9"
  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • ConvertedWallpaper = "%System%\phc3u8j0eral.bmp"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • NoDispBackgroundPage = "1"
  • In HKEY_CURRENT_USER\Software\Sysinternals\Bluescreen Screen Saver
    • EulaAccepted = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • NoDispScrSavPage = "1"

Step 5

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Control Panel\Colors
    • From: Background = "0 0 255"
      To: Background = ""0 78 152""
  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • From: WallpaperStyle = "0"
      To: WallpaperStyle = ""2""
  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • From: TileWallpaper = "0"
      To: TileWallpaper = ""0""
  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • From: Wallpaper = "%System%\phc3u8j0eral.bmp"
      To: Wallpaper = ""%Windows%\web\wallpaper\Bliss.bmp""
  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • OriginalWallpaper = "%System%\phc3u8j0eral.bmp"
  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • From: SCRNSAVE.EXE = "%System%\blphc3u8j0eral.scr"
      To: SCRNSAVE.EXE = ""%Windows%\system32\logon.scr""
  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • From: ScreenSaveActive = "1"
      To: ScreenSaveActive = ""1""
  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • From: ScreenSaveTimeOut = "600"
      To: ScreenSaveTimeOut = ""600""

Step 6

Search and delete these components

[ Learn More ]
There may be some components 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 Temp%\.tt1.tmp.vbs
  • %System%\phc3u8j0eral.bmp
  • %System%\blphc3u8j0eral.scr

Step 7

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

  • %System%\lphc3u8j0eral.exe:Zone.Identifier
  • %User Temp%\.tt6.tmp
  • %User Temp%\.tt9.tmp
  • %User Temp%\.ttC.tmp
  • %User Temp%\.ttF.tmp
  • %User Temp%\.tt12.tmp


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