Ransom.Win32.ERIS.C

 Analysis by: Jemimah Mae Molina

 ALIASES:

Trojan-Ransom.Eris (IKARUS); a variant of Win32/Filecoder.Eris.B trojan (NOD32)

 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 connects to certain websites to send and receive information. It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

1,803,776 bytes

File Type:

EXE

File Compression:

UPX

Memory Resident:

No

Initial Samples Received Date:

05 Aug 2019

Payload:

Terminates processes, 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 processes:

  • taskkill.exe /f /im mysqld.exe
  • taskkill.exe /f /im sqlwriter.exe
  • taskkill.exe /f /im sqlserver.exe
  • taskkill.exe /f /im MSExchange*
  • taskkill.exe /f /im Microsoft.Exchange.*

Process Termination

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

  • sql
  • backup
  • malware
  • server
  • agent
  • http
  • apache

Dropping Routine

This Ransomware drops the following files:

  • %ProgramData%\00000000.pky → contains public key
  • %ProgramData%\00000000.eky → contains encryption key
  • %ProgramData%\00000000.ext → contains file extension of encrypted files

(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit), or C:\Documents and Settings\All Users on Windows Server 2003(32-bit), 2000(32-bit) and XP.)

Other Details

This Ransomware connects to the following URL(s) to get the affected system's IP address:

  • http://extreme-ip{BLOCKED}.com/json

It connects to the following website to send and receive information:

  • http://{BLOCKED}wzczbcbi4edpi4tx3khwbnty3obfhemd5i5gbyci3hxx3k5pad.{BLOCKED}n.pet/api/v1/check
  • http://{BLOCKED}wzczbcbi4edpi4tx3khwbnty3obfhemd5i5gbyci3hxx3k5pad.{BLOCKED}n.pet/api/v1/sync

It does the following:

  • It deletes the shadow volume copies and disables system recovery using the following commands:
    • vssadmin delete shadows /all /quiet
    • wmic shadowcopy delete
    • wbadmin delete catalog -quiet
    • bcdedit /set {default} bootstatuspolicy ignoreallfailures
    • bcdedit /set {default} recoveryenabled no
  • It wipes deleted files from encrypted drives using the following command:
    • cipher /W:{Encrypted Drive Letter}:

It deletes itself after execution.

Ransomware Routine

This Ransomware avoids encrypting files with the following strings in their file name:

  • .sys
  • .com
  • autoexec.bat
  • boot.ini
  • ntdetect.com
  • msdos.sys
  • io.sys
  • pagefile.sys
  • ntuser.dat
  • config.sys
  • ntldr

It avoids encrypting files found in the following folders:

  • windows
  • windows.old
  • system volume information
  • $recycle.bin
  • program files
  • program files (x86)
  • programdata
  • i386
  • amd64
  • sysvol

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

  • .{5 random characters}

It leaves text files that serve as ransom notes containing the following text:

  • {Encrypted Directory}\HELP-{5 random characters}.txt

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.314.04

FIRST VSAPI PATTERN DATE:

22 Aug 2019

VSAPI OPR PATTERN File:

15.315.00

VSAPI OPR PATTERN Date:

23 Aug 2019

Step 1

Trend Micro products with the XGen technology detect this malware as

[ Learn More ]
 
  • Troj.Win32.TRX.XXPE50FFF031

Step 2

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 3

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 4

Search and delete these components

[ Learn More ]
There may be some components 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.
  • %ProgramData%\00000000.pky
  • %ProgramData%\00000000.eky
  • %ProgramData%\00000000.ext
  • {Encrypted Directory}\HELP-{5 random characters}.txt

Step 5

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.ERIS.C. 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.

NOTES:

  • Enabling Volume Shadow Service
    • Run the command prompt (cmd.exe) as administrator.
    • Enable volume shadow service using the following command:
      net start vss
  • Enabling Windows Error Recovery
    • Run the command prompt (cmd.exe) as administrator.
    • Enable Windows error recovery screen on startup using the following command:
      bcdedit /set {default} bootstatuspolicy displayallfailures
  • Enabling Startup Repair
    • Run the command prompt (cmd.exe) as administrator.
    • Enable startup repair using the following command:
      bcedit /set {default} recoveryenabled Yes
  • Restoring Backup Catalog
    • Run the command prompt (cmd.exe) as administrator.
    • Restore backup catalog using the following command:
      wbadmin restore catalog


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