Analysis by: Marcus Ma. Antonio Capistrano

ALIASES:

Trojan-Ransom.Win32.Crypren.adyi (KASPERSKY), Troj/WHappy-A (SOPHOS_LITE), W32/Crypren.ADYI!tr (FORTINET)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: No

  • 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.

It is capable of encrypting files in the affected system.

  TECHNICAL DETAILS

File Size: 297,472 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 26 Oct 2017
Payload: Displays message/message boxes, Encrypts files, Connects to URLs/IPs

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.

Autostart Technique

This Ransomware modifies the following registry entry(ies) to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Wannabehappy = {malware file path}

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_CURRENT_USER\Software\WannabeHappy\
EncryptionKeyGenerated
IsGenerated = True

HKEY_CURRENT_USER\Software\WannabeHappy\
Identifier
identifier = {random 20 character string}

HKEY_CURRENT_USER\Software\WannabeHappy\
Identifier
readme = The identifier is your unique identifier to receive your encryptionkey, if removed the encryptionkey can not be returned...So be warned!

HKEY_CURRENT_USER\Software\WannabeHappy\
Encryption
Successfull = True

HKEY_CURRENT_USER\Software\WannabeHappy\
Value
value = {date and time when the malware was run}

HKEY_CURRENT_USER\Software\WannabeHappy\
EncryptionKey
Key{0-999} = {random 40 digit string}

HKEY_CURRENT_USER\Software\WannabeHappy\
EncryptionKey (This registry key is only created when it successfully communicates with c&c server)
Key = {random 200 character string}

HKEY_CURRENT_USER\Software\WannabeHappy\
EncryptionStarted (This registry key is only created when it successfully communicates with c&c server)
EncryptionStarted = True

Information Theft

This Ransomware gathers the following data:

  • Public IP address
  • MAC address

Stolen Information

This Ransomware sends the gathered information via HTTP POST to the following URL:

  • {BLOCKED}.{BLOCKED}.77.189:8443

Other Details

This Ransomware does the following:

  • If the ransomware successfully communicates with the c&c server, it displays the following window:
  • After encryption routine it displays the following window:
  • This ransomware avoids encrypting files with file size of 8,388,608 bytes or higher

It is capable of encrypting files in the affected system.

Ransomware Routine

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

  • .encrypted

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.744.04
FIRST VSAPI PATTERN DATE: 27 Oct 2017
VSAPI OPR PATTERN File: 13.745.00
VSAPI OPR PATTERN Date: 28 Oct 2017

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_WANNAHAPPY.A

[ 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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

 
  • HKEY_CURRENT_USER\Software\WannabeHappy

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\Run
    • Wannabehappy = {malware file path}

Step 6

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

Step 7

Restore encrypted files from backup.


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