RANSOM_ENCRYPTILE.A

November 17, 2016
 Analysis by: Jeanne Jocson
 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

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 itself after execution.

  TECHNICAL DETAILS

File Size:

651,264 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

18 Jul 2016

Payload:

Drops files, Encrypts files

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 adds the following mutexes to ensure that only one of its copies runs at any one time:

  • 68765eyui0

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\RunOnce
Service Runtime = "%AppDataLocal%\encryptile.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run
Service Runtime = "%AppDataLocal%\encryptile.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Service Runtime = "%AppDataLocal%\encryptile.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
Service RUntime = "%AppDataLocal%\encryptile.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run
*Unikey Manager = "{malware path}"

HKEY_LOCAL_MACHINE\Microsoft\Windows\
CurrentVersion\Policies\System
EnableLUA = "0"

HKEY_LOCAL_MACHINE\Microsoft\Windows\
CurrentVersion\Policies\System
ConsentPromptBehaviorAdmin = "0"

HKEY_LOCAL_MACHINE\Microsoft\Windows\
CurrentVersion\Policies\System
PromptOnSecureDesktop= = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoControlPanel = "1"

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

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

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer

Process Termination

This Trojan terminates processes or services that contain any of the following strings if found running in the affected system's memory:

  • taskmgr
  • msconfig
  • regedit
  • Taskmgr
  • procexp
  • ProcessHacker

Dropping Routine

This Trojan drops the following files:

  • %AppDataLocal%\encryptile.exe:Zone.Identifier
  • %AppDataLocal%\Readlist.txt-contains the list of encrypted files
  • %AppDataLocal%\encryptile.exe
  • %AppDataLocal%\dllhost.exe
  • %AppDataLocal%\Shellcode.dll
  • %AppDataLocal%\language_902_______.txt
  • %AppDataLocal%\559023849238.dll
  • %AppDataLocal%\559023849238.jar
  • %AppDataLocal%\bitcoin_pay.txt
  • %AppDataLocal%\notepad.exe

(Note: %AppDataLocal% is the Application Data folder found in Local Settings, where it is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local 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.)

Other Details

This Trojan sets the attributes of the following file(s) to Hidden and System:

  • %AppDataLocal%\notepad.exe
  • %AppDataLocal%\dllhost.exe

(Note: %AppDataLocal% is the Application Data folder found in Local Settings, where it is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local 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.)

It does the following:

  • Exempt files with the following extensions from encryption:
    • .exe
    • .sys
    • .dll
    • .ini
    • .log
    • .dsk
    • .inf
    • .pnf
    • .msi
    • .mui
    • .dat
    • .vbs
    • .bat
    • .mof
    • .ttc
    • .lnk
    • .xml
    • .bdic
    • .bin
    • .pak
    • .json
    • .crx
    • .scr
    • .msp
    • .com
    • .hta
    • .cpl
    • .msc
    • .cmd
    • .scf
    • .scr
    • .wav
  • Exempt files that contains the following strings in their file path from encryption:
    • ttf
    • fon
    • -ms
    • 559023849238
    • encryptile
    • readlist
    • mftcompilerdata
    • defragdata
    • bitcoin_pay
    • \microsoft\
    • language_902_______
    • \google\
    • \browser\
    • %Windows%
    • %User Temp%
    • %Cookies%
    • %Temporary Internet Files%
  • Terminates processes that has the following strings in their Window Title:
    • AntiRansom
    • Task Manager
    • Registry Editor
    • System Configuration
    • ransomware
    • antivirus
    • system restore
    • sysinternals
    • Process Hacker
    • Facebook
    • Twitter
    • Instagram
    • YouTube
    • Tumblr
    • hacked
    • porn
    • police
    • 1080
    • 720
    • movie
  • Deletes System Restore Points

It deletes itself after execution.

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

12.864.06

FIRST VSAPI PATTERN DATE:

28 Oct 2016

VSAPI OPR PATTERN File:

12.865.00

VSAPI OPR PATTERN Date:

29 Oct 2016

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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\Windows\CurrentVersion\Policies\Explorer
    • Run
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies
    • Explorer
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies
    • Explorer

Step 5

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
    • Service Runtime = "%AppDataLocal%\encryptile.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Service Runtime = "%AppDataLocal%\encryptile.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
    • Service RUntime = "%AppDataLocal%\encryptile.exe"
  • In HKEY_LOCAL_MACHINE\Microsoft\Windows\CurrentVersion\Policies\System
    • EnableLUA = "0"
  • In HKEY_LOCAL_MACHINE\Microsoft\Windows\CurrentVersion\Policies\System
    • ConsentPromptBehaviorAdmin = "0"
  • In HKEY_LOCAL_MACHINE\Microsoft\Windows\CurrentVersion\Policies\System
    • PromptOnSecureDesktop = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • DisableTaskMgr = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • DisableRegistryTools = "1"

Step 6

Search and delete this file

[ Learn More ]
There may be some 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.
  • %AppDataLocal%\Readlist.txt
  • %AppDataLocal%\encryptile.exe
  • %AppDataLocal%\notepad.exe
  • %AppDataLocal%\dllhost.exe
  • %AppDataLocal%\Shellcode.dll
  • %AppDataLocal%\language_902_______.txt
  • %AppDataLocal%\559023849238.dll
  • %AppDataLocal%\559023849238.jar
  • %AppDataLocal%\bitcoin_pay.txt
  • %AppDataLocal%\encryptile.exe:Zone.Identifier

Step 7

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