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Ransom_CRYPTESLA.YALA

June 14, 2016
 PLATFORM:

Windows

 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:

109,568 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

14 Jun 2016

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 copies of itself into the affected system:

  • %User Profile%\Application Data\AdobeFlashPlayer_68ad0fd0cc58263a.exe
  • A:\Microsoft Adobe Reader Attention.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

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
Adobe Reader UpdateHardWare = "{malware path and file name} "

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
*Adobe Reader Update32 = "{random values}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
AdobeFlashPlayersHardWare = "{random characters}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
*AdobeFlashPlayers32 = "%User Profile%\Application Data\AdobeFlashPlayer_68ad0fd0cc58263a.exe "

Other System Modifications

This Trojan deletes the following files:

  • {malware path and file name}:zone.identifier
  • %User Profile%\Application Data\AdobeFlashPlayer_68ad0fd0cc58263a.exe:Zone.Identifier

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

It adds the following registry entries:

HKEY_CURRENT_USER\Software
AdobeFirstVersionHardWare32 = "{malware path and file name}"

HKEY_CURRENT_USER\Software
AdobeLicensionHWare = "{random values}"

HKEY_CURRENT_USER\Software
AdobeFirstVersionHardWare32 = "TheEnd"

Dropping Routine

This Trojan drops the following files:

  • A:\HELP_YOUR_FILES.TXT
  • A:\HELP_YOUR_FILES.HTML
  • %System Root%\HELP_YOUR_FILES.TXT
  • %System Root%\HELP_YOUR_FILES.HTML
  • %System Root%\Documents and Settings\HELP_YOUR_FILES.TXT
  • %System Root%\Documents and Settings\HELP_YOUR_FILES.HTML
  • %User Profile%\HELP_YOUR_FILES.TXT
  • %User Profile%\HELP_YOUR_FILES.HTML
  • %User Profile%\Application Data\HELP_YOUR_FILES.TXT
  • %User Profile%\Application Data\HELP_YOUR_FILES.HTML
  • %User Profile%\Documents\HELP_YOUR_FILES.TXT
  • %User Profile%\Documents\HELP_YOUR_FILES.HTML
  • %User Profile%\My Music\HELP_YOUR_FILES.TXT
  • %User Profile%\My Music\HELP_YOUR_FILES.HTML
  • %User Profile%\My Playlists\HELP_YOUR_FILES.TXT
  • %User Profile%\My Playlists\HELP_YOUR_FILES.HTML
  • %User Profile%\Sample Music\HELP_YOUR_FILES.TXT
  • %User Profile%\Sample Music\HELP_YOUR_FILES.HTML
  • %User Profile%\Sample Playlists\HELP_YOUR_FILES.TXT
  • %User Profile%\Sample Playlists\HELP_YOUR_FILES.HTML
  • %User Profile%\0008044E\HELP_YOUR_FILES.TXT
  • %User Profile%\0008044E\HELP_YOUR_FILES.HTML
  • %User Profile%\My Pictures\HELP_YOUR_FILES.TXT
  • %User Profile%\My Pictures\HELP_YOUR_FILES.HTML
  • %User Profile%\Sample Pictures\HELP_YOUR_FILES.TXT
  • %User Profile%\Sample Pictures\HELP_YOUR_FILES.HTML
  • %User Profile%\My Videos\HELP_YOUR_FILES.TXT
  • %User Profile%\My Videos\HELP_YOUR_FILES.HTML
  • %User Profile%\DRM\HELP_YOUR_FILES.TXT
  • %User Profile%\DRM\HELP_YOUR_FILES.HTML
  • %Favorites%\HELP_YOUR_FILES.TXT
  • %Favorites%\HELP_YOUR_FILES.HTML
  • %Start Menu%\HELP_YOUR_FILES.TXT
  • %Start Menu%\HELP_YOUR_FILES.HTML
  • %Start Menu%\Programs\HELP_YOUR_FILES.TXT
  • %Start Menu%\Programs\HELP_YOUR_FILES.HTML
  • %Start Menu%\Programs\Accessories\HELP_YOUR_FILES.TXT
  • %Start Menu%\Programs\Accessories\HELP_YOUR_FILES.HTML
  • %Start Menu%\Programs\Accessories\Accessibility\HELP_YOUR_FILES.TXT
  • %Start Menu%\Programs\Accessories\Accessibility\HELP_YOUR_FILES.HTML
  • %Start Menu%\Programs\Accessories\Communications\HELP_YOUR_FILES.TXT
  • %Start Menu%\Programs\Accessories\Communications\HELP_YOUR_FILES.HTML
  • %Start Menu%\Programs\Accessories\Entertainment\HELP_YOUR_FILES.TXT
  • %Start Menu%\Programs\Accessories\Entertainment\HELP_YOUR_FILES.HTML
  • %Start Menu%\Programs\Accessories\System Tools\HELP_YOUR_FILES.TXT
  • %Start Menu%\Programs\Accessories\System Tools\HELP_YOUR_FILES.HTML
  • %Start Menu%\Programs\Administrative Tools\HELP_YOUR_FILES.TXT
  • %Start Menu%\Programs\Administrative Tools\HELP_YOUR_FILES.HTML
  • %Start Menu%\Programs\Games\HELP_YOUR_FILES.TXT
  • %Start Menu%\Programs\Games\HELP_YOUR_FILES.HTML
  • %Common Startup%\HELP_YOUR_FILES.TXT
  • %Common Startup%\HELP_YOUR_FILES.HTML
  • %Start Menu%\Programs\WinPcap\HELP_YOUR_FILES.TXT
  • %Start Menu%\Programs\WinPcap\HELP_YOUR_FILES.HTML
  • %User Profile%\Templates\HELP_YOUR_FILES.TXT
  • %User Profile%\Templates\HELP_YOUR_FILES.HTML
  • %User Profile%\Cookies\HELP_YOUR_FILES.TXT
  • %User Profile%\Cookies\HELP_YOUR_FILES.HTML
  • %User Profile%\Local Settings\HELP_YOUR_FILES.TXT
  • %User Profile%\Local Settings\HELP_YOUR_FILES.HTML
  • %Application Data%\HELP_YOUR_FILES.TXT
  • %Application Data%\HELP_YOUR_FILES.HTML
  • %User Profile%\History\HELP_YOUR_FILES.TXT
  • %User Profile%\History\HELP_YOUR_FILES.HTML
  • %User Profile%\History.IE5\HELP_YOUR_FILES.TXT
  • %User Profile%\History.IE5\HELP_YOUR_FILES.HTML
  • %User Temp%\HELP_YOUR_FILES.TXT
  • %User Temp%\HELP_YOUR_FILES.HTML
  • %Temporary Internet Files%\HELP_YOUR_FILES.TXT
  • %Temporary Internet Files%\HELP_YOUR_FILES.HTML
  • %User Profile%\My Documents\HELP_YOUR_FILES.TXT
  • %User Profile%\My Documents\HELP_YOUR_FILES.HTML
  • %User Profile%\NetHood\HELP_YOUR_FILES.TXT
  • %User Profile%\NetHood\HELP_YOUR_FILES.HTML
  • %User Profile%\PrintHood\HELP_YOUR_FILES.TXT
  • %User Profile%\PrintHood\HELP_YOUR_FILES.HTML
  • %User Profile%\Recent\HELP_YOUR_FILES.TXT
  • %User Profile%\Recent\HELP_YOUR_FILES.HTML
  • %User Profile%\SendTo\HELP_YOUR_FILES.TXT
  • %User Profile%\SendTo\HELP_YOUR_FILES.HTML
  • %User Startup%\HELP_YOUR_FILES.TXT
  • %User Startup%\HELP_YOUR_FILES.HTML
  • %Favorites%\Links\HELP_YOUR_FILES.TXT
  • %Favorites%\Links\HELP_YOUR_FILES.HTML
  • %User Profile%\MSHist012013061320130614\HELP_YOUR_FILES.TXT
  • %User Profile%\MSHist012013061320130614\HELP_YOUR_FILES.HTML
  • %Program Files%\HELP_YOUR_FILES.TXT
  • %Program Files%\HELP_YOUR_FILES.HTML
  • %System Root%\System Volume Information\HELP_YOUR_FILES.TXT
  • %System Root%\System Volume Information\HELP_YOUR_FILES.HTML
  • %Windows%\HELP_YOUR_FILES.TXT
  • %Windows%\HELP_YOUR_FILES.HTML
  • %Desktop%\HELP_YOUR_FILES.TXT
  • %Desktop%\HELP_YOUR_FILES.HTML

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %Favorites% is the Favorites folder, where it usually is C:\Documents and Settings\{user name}\Favorites on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\Favorites on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %Start Menu% is the Start Menu folder, where it usually is C:\Documents and Settings\{user name}\Start Menu on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %Common Startup% is the system's shared Startup folder, which is usually C:\Documents and Settings\All Users\Start Menu\Programs\Startup on Windows 2000, XP, and Server 2003, and C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, and 8.. %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %Temporary Internet Files% is the Temporary Internet Files folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temporary Internet Files on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Microsoft\Windows\Temporary Internet Files on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), and Windows Server 2008; C:\Users\{user name}\AppData\Local\Microsoft\Windows\INetCache on Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), and Windows Server 2012.. %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.. %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %Desktop% is the desktop folder, where it usually is C:\Documents and Settings\{user name}\Desktop in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\Desktop in Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}.253.80/default.jpg
  • {BLOCKED}.195.251

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.8

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 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
    • Adobe Reader UpdateHardWare = "{malware path and file name} "
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
    • *Adobe Reader Update32 = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • AdobeFlashPlayersHardWare = "{random characters}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
    • *AdobeFlashPlayers32 = "%User Profile%\Application Data\AdobeFlashPlayer_68ad0fd0cc58263a.exe "
  • In HKEY_CURRENT_USER\Software
    • AdobeFirstVersionHardWare32 = "{malware path and file name}"
  • In HKEY_CURRENT_USER\Software
    • AdobeLicensionHWare = "{random values}"
  • In HKEY_CURRENT_USER\Software
    • AdobeFirstVersionHardWare32 = "TheEnd"

Step 4

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.
  • A:\HELP_YOUR_FILES.TXT
  • A:\HELP_YOUR_FILES.HTML
  • %System Root%\HELP_YOUR_FILES.TXT
  • %System Root%\HELP_YOUR_FILES.HTML
  • %System Root%\Documents and Settings\HELP_YOUR_FILES.TXT
  • %System Root%\Documents and Settings\HELP_YOUR_FILES.HTML
  • %User Profile%\HELP_YOUR_FILES.TXT
  • %User Profile%\HELP_YOUR_FILES.HTML
  • %User Profile%\Application Data\HELP_YOUR_FILES.TXT
  • %User Profile%\Application Data\HELP_YOUR_FILES.HTML
  • %User Profile%\Documents\HELP_YOUR_FILES.TXT
  • %User Profile%\Documents\HELP_YOUR_FILES.HTML
  • %User Profile%\My Music\HELP_YOUR_FILES.TXT
  • %User Profile%\My Music\HELP_YOUR_FILES.HTML
  • %User Profile%\My Playlists\HELP_YOUR_FILES.TXT
  • %User Profile%\My Playlists\HELP_YOUR_FILES.HTML
  • %User Profile%\Sample Music\HELP_YOUR_FILES.TXT
  • %User Profile%\Sample Music\HELP_YOUR_FILES.HTML
  • %User Profile%\Sample Playlists\HELP_YOUR_FILES.TXT
  • %User Profile%\Sample Playlists\HELP_YOUR_FILES.HTML
  • %User Profile%\0008044E\HELP_YOUR_FILES.TXT
  • %User Profile%\0008044E\HELP_YOUR_FILES.HTML
  • %User Profile%\My Pictures\HELP_YOUR_FILES.TXT
  • %User Profile%\My Pictures\HELP_YOUR_FILES.HTML
  • %User Profile%\Sample Pictures\HELP_YOUR_FILES.TXT
  • %User Profile%\Sample Pictures\HELP_YOUR_FILES.HTML
  • %User Profile%\My Videos\HELP_YOUR_FILES.TXT
  • %User Profile%\My Videos\HELP_YOUR_FILES.HTML
  • %User Profile%\DRM\HELP_YOUR_FILES.TXT
  • %User Profile%\DRM\HELP_YOUR_FILES.HTML
  • %Favorites%\HELP_YOUR_FILES.TXT
  • %Favorites%\HELP_YOUR_FILES.HTML
  • %Start Menu%\HELP_YOUR_FILES.TXT
  • %Start Menu%\HELP_YOUR_FILES.HTML
  • %Start Menu%\Programs\HELP_YOUR_FILES.TXT
  • %Start Menu%\Programs\HELP_YOUR_FILES.HTML
  • %Start Menu%\Programs\Accessories\HELP_YOUR_FILES.TXT
  • %Start Menu%\Programs\Accessories\HELP_YOUR_FILES.HTML
  • %Start Menu%\Programs\Accessories\Accessibility\HELP_YOUR_FILES.TXT
  • %Start Menu%\Programs\Accessories\Accessibility\HELP_YOUR_FILES.HTML
  • %Start Menu%\Programs\Accessories\Communications\HELP_YOUR_FILES.TXT
  • %Start Menu%\Programs\Accessories\Communications\HELP_YOUR_FILES.HTML
  • %Start Menu%\Programs\Accessories\Entertainment\HELP_YOUR_FILES.TXT
  • %Start Menu%\Programs\Accessories\Entertainment\HELP_YOUR_FILES.HTML
  • %Start Menu%\Programs\Accessories\System Tools\HELP_YOUR_FILES.TXT
  • %Start Menu%\Programs\Accessories\System Tools\HELP_YOUR_FILES.HTML
  • %Start Menu%\Programs\Administrative Tools\HELP_YOUR_FILES.TXT
  • %Start Menu%\Programs\Administrative Tools\HELP_YOUR_FILES.HTML
  • %Start Menu%\Programs\Games\HELP_YOUR_FILES.TXT
  • %Start Menu%\Programs\Games\HELP_YOUR_FILES.HTML
  • %Common Startup%\HELP_YOUR_FILES.TXT
  • %Common Startup%\HELP_YOUR_FILES.HTML
  • %Start Menu%\Programs\WinPcap\HELP_YOUR_FILES.TXT
  • %Start Menu%\Programs\WinPcap\HELP_YOUR_FILES.HTML
  • %User Profile%\Templates\HELP_YOUR_FILES.TXT
  • %User Profile%\Templates\HELP_YOUR_FILES.HTML
  • %User Profile%\Cookies\HELP_YOUR_FILES.TXT
  • %User Profile%\Cookies\HELP_YOUR_FILES.HTML
  • %User Profile%\Local Settings\HELP_YOUR_FILES.TXT
  • %User Profile%\Local Settings\HELP_YOUR_FILES.HTML
  • %Application Data%\HELP_YOUR_FILES.TXT
  • %Application Data%\HELP_YOUR_FILES.HTML
  • %User Profile%\History\HELP_YOUR_FILES.TXT
  • %User Profile%\History\HELP_YOUR_FILES.HTML
  • %User Profile%\History.IE5\HELP_YOUR_FILES.TXT
  • %User Profile%\History.IE5\HELP_YOUR_FILES.HTML
  • %User Temp%\HELP_YOUR_FILES.TXT
  • %User Temp%\HELP_YOUR_FILES.HTML
  • %Temporary Internet Files%\HELP_YOUR_FILES.TXT
  • %Temporary Internet Files%\HELP_YOUR_FILES.HTML
  • %User Profile%\My Documents\HELP_YOUR_FILES.TXT
  • %User Profile%\My Documents\HELP_YOUR_FILES.HTML
  • %User Profile%\NetHood\HELP_YOUR_FILES.TXT
  • %User Profile%\NetHood\HELP_YOUR_FILES.HTML
  • %User Profile%\PrintHood\HELP_YOUR_FILES.TXT
  • %User Profile%\PrintHood\HELP_YOUR_FILES.HTML
  • %User Profile%\Recent\HELP_YOUR_FILES.TXT
  • %User Profile%\Recent\HELP_YOUR_FILES.HTML
  • %User Profile%\SendTo\HELP_YOUR_FILES.TXT
  • %User Profile%\SendTo\HELP_YOUR_FILES.HTML
  • %User Startup%\HELP_YOUR_FILES.TXT
  • %User Startup%\HELP_YOUR_FILES.HTML
  • %Favorites%\Links\HELP_YOUR_FILES.TXT
  • %Favorites%\Links\HELP_YOUR_FILES.HTML
  • %User Profile%\MSHist012013061320130614\HELP_YOUR_FILES.TXT
  • %User Profile%\MSHist012013061320130614\HELP_YOUR_FILES.HTML
  • %Program Files%\HELP_YOUR_FILES.TXT
  • %Program Files%\HELP_YOUR_FILES.HTML
  • %System Root%\System Volume Information\HELP_YOUR_FILES.TXT
  • %System Root%\System Volume Information\HELP_YOUR_FILES.HTML
  • %Windows%\HELP_YOUR_FILES.TXT
  • %Windows%\HELP_YOUR_FILES.HTML
  • %Desktop%\HELP_YOUR_FILES.TXT
  • %Desktop%\HELP_YOUR_FILES.HTML

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom_CRYPTESLA.YALA. 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 6

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.

  • {malware path and file name}:zone.identifier
  • %User Profile%\Application Data\AdobeFlashPlayer_68ad0fd0cc58263a.exe:Zone.Identifier


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