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Ransom_PYLOCKY.THHCAAH

September 10, 2018
 ALIASES:

Trojan:Win32/Occamy.C (Microsoft), Trojan-Ransom.Win32.Encoder.gv (Kaspersky)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Ransomware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It drops files as ransom note.

  TECHNICAL DETAILS

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

27 Aug 2018

Arrival Details

This Ransomware 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 Ransomware drops the following files:

  • %User Temp%\is-{Random Characters}.tmp\{Malware Filename}.tmp
  • %User Temp%\is-{Random Characters}.tmp\bz2.pyd
  • %User Temp%\is-{Random Characters}.tmp\Crypto.Cipher._AES.pyd
  • %User Temp%\is-{Random Characters}.tmp\Crypto.Cipher._DES.pyd
  • %User Temp%\is-{Random Characters}.tmp\Crypto.Cipher._DES3.pyd
  • %User Temp%\is-{Random Characters}.tmp\Crypto.Hash._SHA256.pyd
  • %User Temp%\is-{Random Characters}.tmp\Crypto.Random.OSRNG.winrandom.pyd
  • %User Temp%\is-{Random Characters}.tmp\Crypto.Util.strxor.pyd
  • %User Temp%\is-{Random Characters}.tmp\Crypto.Util._counter.pyd
  • %User Temp%\is-{Random Characters}.tmp\lockyfud.exe
  • %User Temp%\is-{Random Characters}.tmp\lockyfud.exe.manifest
  • %User Temp%\is-{Random Characters}.tmp\mfc90.dll
  • %User Temp%\is-{Random Characters}.tmp\mfc90u.dll
  • %User Temp%\is-{Random Characters}.tmp\mfcm90.dll
  • %User Temp%\is-{Random Characters}.tmp\mfcm90u.dll
  • %User Temp%\is-{Random Characters}.tmp\Microsoft.VC90.CRT.manifest
  • %User Temp%\is-{Random Characters}.tmp\Microsoft.VC90.MFC.manifest
  • %User Temp%\is-{Random Characters}.tmp\msvcm90.dll
  • %User Temp%\is-{Random Characters}.tmp\msvcp90.dll
  • %User Temp%\is-{Random Characters}.tmp\msvcr90.dll
  • %User Temp%\is-{Random Characters}.tmp\python27.dll
  • %User Temp%\is-{Random Characters}.tmp\pythoncom27.dll
  • %User Temp%\is-{Random Characters}.tmp\pywintypes27.dll
  • %User Temp%\is-{Random Characters}.tmp\select.pyd
  • %User Temp%\is-{Random Characters}.tmp\unicodedata.pyd
  • %User Temp%\is-{Random Characters}.tmp\win32api.pyd
  • %User Temp%\is-{Random Characters}.tmp\win32trace.pyd
  • %User Temp%\is-{Random Characters}.tmp\win32ui.pyd
  • %User Temp%\is-{Random Characters}.tmp\_ctypes.pyd
  • %User Temp%\is-{Random Characters}.tmp\_hashlib.pyd
  • %User Temp%\is-{Random Characters}.tmp\_win32sysloader.pyd
  • %User Temp%\{Random Letters}\gen_py\__init__.py
  • %User Temp%\{Random Letters}\gen_py\dicts.dat

(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, 7, and 8.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
MyProgram = "%User Temp%\is-{Random Character}.tmp\lockyfud.exe"

Ransomware Routine

This Ransomware appends the following extension to the file name of the encrypted files:

  • .lockymap
  • .lockedfile

It drops the following file(s) as ransom note:

  • {Every Folder}\LOCKY-README.txt

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.476.03

FIRST VSAPI PATTERN DATE:

31 Aug 2018

VSAPI OPR PATTERN File:

14.477.00

VSAPI OPR PATTERN Date:

01 Sep 2018

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

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
    • MyProgram = "%User Temp%\is-{Random Character}.tmp\lockyfud.exe"

Step 4

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.  
  • %User Temp%\is-{Random Characters}.tmp\{Malware Filename}.tmp
  • %User Temp%\is-{Random Characters}.tmp\bz2.pyd
  • %User Temp%\is-{Random Characters}.tmp\Crypto.Cipher._AES.pyd
  • %User Temp%\is-{Random Characters}.tmp\Crypto.Cipher._DES.pyd
  • %User Temp%\is-{Random Characters}.tmp\Crypto.Cipher._DES3.pyd
  • %User Temp%\is-{Random Characters}.tmp\Crypto.Hash._SHA256.pyd
  • %User Temp%\is-{Random Characters}.tmp\Crypto.Random.OSRNG.winrandom.pyd
  • %User Temp%\is-{Random Characters}.tmp\Crypto.Util.strxor.pyd
  • %User Temp%\is-{Random Characters}.tmp\Crypto.Util._counter.pyd
  • %User Temp%\is-{Random Characters}.tmp\lockyfud.exe
  • %User Temp%\is-{Random Characters}.tmp\lockyfud.exe.manifest
  • %User Temp%\is-{Random Characters}.tmp\mfc90.dll
  • %User Temp%\is-{Random Characters}.tmp\mfc90u.dll
  • %User Temp%\is-{Random Characters}.tmp\mfcm90.dll
  • %User Temp%\is-{Random Characters}.tmp\mfcm90u.dll
  • %User Temp%\is-{Random Characters}.tmp\Microsoft.VC90.CRT.manifest
  • %User Temp%\is-{Random Characters}.tmp\Microsoft.VC90.MFC.manifest
  • %User Temp%\is-{Random Characters}.tmp\msvcm90.dll
  • %User Temp%\is-{Random Characters}.tmp\msvcp90.dll
  • %User Temp%\is-{Random Characters}.tmp\msvcr90.dll
  • %User Temp%\is-{Random Characters}.tmp\python27.dll
  • %User Temp%\is-{Random Characters}.tmp\pythoncom27.dll
  • %User Temp%\is-{Random Characters}.tmp\pywintypes27.dll
  • %User Temp%\is-{Random Characters}.tmp\select.pyd
  • %User Temp%\is-{Random Characters}.tmp\unicodedata.pyd
  • %User Temp%\is-{Random Characters}.tmp\win32api.pyd
  • %User Temp%\is-{Random Characters}.tmp\win32trace.pyd
  • %User Temp%\is-{Random Characters}.tmp\win32ui.pyd
  • %User Temp%\is-{Random Characters}.tmp\_ctypes.pyd
  • %User Temp%\is-{Random Characters}.tmp\_hashlib.pyd
  • %User Temp%\is-{Random Characters}.tmp\_win32sysloader.pyd
  • %User Temp%\{Random Letters}\gen_py\__init__.py
  • %User Temp%\{Random Letters}\gen_py\dicts.dat

Step 5

Scan your computer with your Trend Micro product to delete files detected as Ransom_PYLOCKY.THHCAAH. 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 the following Trend Micro Support pages for more information:

Step 6

Restore encrypted files from backup.


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