Analysis by: Michael Jhon Ofiaza
ALIASES:

Ransom:MSIL/WannaPeace.A (Microsoft) ; Trojan-Ransom.MSIL.Agent.aar (Kaspersky) ; Trojan Horse (Norton)

 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: Dropped by other malware, 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 encrypts files found in specific folders.

  TECHNICAL DETAILS

File Size: 674,816 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 29 Nov 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.

Installation

This Ransomware drops the following files:

  • %Program Files%\drivers.txt

(Note: %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.)

Other Details

This Ransomware connects to the following time servers to determine the current date:

  • http://www.horacerta.com.br/

Ransomware Routine

This Ransomware encrypts files found in the following folders:

  • %Windows%\testes

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

It renames encrypted files using the following names:

  • {Filename}_enc.{Extension}

NOTES:

This ransomware displays the following after encryption:

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.812.08
FIRST VSAPI PATTERN DATE: 29 Nov 2017
VSAPI OPR PATTERN File: 13.813.00
VSAPI OPR PATTERN Date: 30 Nov 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_WPEACE.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

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.  
  • %Program Files%\drivers.txt

Step 5

Scan your computer with your Trend Micro product to delete files detected as RANSOM_WPEACE.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 6

Restore encrypted files from backup.


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