Analysis by: John Rey Canon

ALIASES:

W32/Crypren.AK!tr (Fortinet); Ransom:Win32/Genasom (Microsoft); Ransom.Ufukt (Malwarebytes)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet

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.

However, as of this writing, the said sites are inaccessible. It is capable of encrypting files in the affected system.

It encrypts files with specific file extensions. It drops files as ransom note.

  TECHNICAL DETAILS

File Size: 970,240 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 18 Sep 2018
Payload: Connects to URLs/IPs, Displays message/message boxes, Encrypts files

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

  • IT.Books

Other System Modifications

This Ransomware adds the following registry keys:

HKEY_CURRENT_USER\Software\Developed by Gehan Fernando.\
IT.Books
1.0.0.0 = ""

It sets the system's desktop wallpaper to the following image:

Other Details

This Ransomware does the following:

  • It avoids encrypting files with specific strings in folder path:
    • Windows
    • AppData
    • Boot
  • It avoids encrypting files with specific strings in file name:
    • READ__IT
  • Displays a message after encrypting files:
    • saw.jpg
  • Accessed the following URLs:
    • http://{BLOCKED}cs.com/polo/chat.php
    • http://{BLOCKED}cs.com/polo/getter.php

However, as of this writing, the said sites are inaccessible.

It is capable of encrypting files in the affected system.

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .asp
  • .aspx
  • .csv
  • .dll
  • .doc
  • .docx
  • .exe
  • .htm
  • .html
  • .ini
  • .jpg
  • .mdb
  • .msi
  • .odt
  • .pdf
  • .php
  • .png
  • .ppt
  • .pptx
  • .psd
  • .rar
  • .sln
  • .sql
  • .txt
  • .xls
  • .xlsx
  • .xml
  • .zip

It appends the following extension to the file name of the encrypted files:

  • .fucked

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

  • %Desktop%\READ__IT.txt

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.512.03
FIRST VSAPI PATTERN DATE: 18 Sep 2018
VSAPI OPR PATTERN File: 14.513.00
VSAPI OPR PATTERN Date: 19 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

Identify and terminate files detected as RANSOM_ITBOOK.THIAHAH

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

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\Developed by Gehan Fernando.\IT.Books
    • 1.0.0.0

Step 5

Search and delete files detected as RANSOM_ITBOOK.THIAHAH

[ 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.  
  • %Desktop%\READ__IT.txt

Step 6

Scan your computer with your Trend Micro product to delete files detected as RANSOM_ITBOOK.THIAHAH. 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 7

Restore encrypted files from backup.


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