Analysis by: Mohammed Malubay
ALIASES:

Trojan:Win32/Coroxy.MR!MTB(MICROSOFT); HEUR:Trojan.Win32.Zenpak.pef(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

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 executes then deletes itself afterward.

It avoids encrypting files with the following file extensions.

  TECHNICAL DETAILS

File Size: 204,800 bytes
File Type: EXE
Initial Samples Received Date: 08 Feb 2021
Payload: Deletes files, Terminates processes

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 executes then deletes itself afterward.

Process Termination

This Ransomware terminates the following services if found on the affected system:

  • Lotus*
  • veeam*
  • cbvscserv*
  • hMailServer
  • backup*
  • *backup*
  • apach*
  • firebird*
  • ibmiasrw
  • IBM Domino*
  • Simply Accounting Database Connection Manager
  • IASJet
  • QB*
  • *sql*
  • sql*
  • QuickBooksDB*
  • IISADMIN
  • omsad
  • dc*32
  • server Administrator
  • wbengine
  • mr2kserv
  • MSExchange*
  • ShadowProtectSvc
  • SP*4
  • teamviewer
  • MMS
  • AcronisAgent
  • ARSM
  • AcrSch2Svc
  • vsnapvss
  • SPXService
  • StorageCraft ImageManager
  • wrsvc
  • stc_endpt_svc
  • acrsch2svc*

It terminates the following processes if found running in the affected system's memory:

  • nslsvice.exe
  • pg*
  • nservice.exe
  • cbvscserv*
  • ntrtscan.exe
  • cbservi*
  • hMailServer*
  • IBM*
  • bes10*
  • black*
  • apach*
  • bd2*
  • db*
  • ba*
  • be*
  • QB*
  • oracle*
  • wbengine*
  • vee*
  • postg*
  • sage*
  • sap*
  • b1*
  • fdlaunch*
  • msmdsrv*
  • report*
  • msdtssr*
  • coldfus*
  • cfdot*
  • swag*
  • swstrtr*
  • jetty.exe
  • wrsa.exe
  • team*
  • agent*
  • store.exe
  • sql*
  • sqbcoreservice.exe
  • thunderbird.exe
  • ocssd.exe
  • encsvc.exe
  • excel.exe
  • synctime.exe
  • mspub.exe
  • ocautoupds.exe
  • thebat.exe
  • dbeng50.exe
  • *sql*
  • mydesktopservice.exe
  • onenote.exe
  • outlook.exe
  • powerpnt.exe
  • msaccess.exe
  • tbirdconfig.exe
  • wordpad.exe
  • ocomm.exe
  • dbsnmp.exe
  • thebat64.exe
  • winword.exe
  • oracle.exe
  • xfssvccon.exe
  • firefoxconfig.exe
  • visio.exe
  • mydesktopqos.exe
  • infopath.exe
  • agntsvc.exe

Other Details

This Ransomware does the following:

  • It encrypts all drives.
  • It deletes scheduled tasks with arguments containing the following strings:
    • reboot
    • restart
    • shutdown
    • logoff
    • back

Ransomware Routine

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

  • ntuser.dat*
  • iconcache.db
  • gdipfont*.dat
  • ntuser.ini
  • usrclass.dat
  • usrclass.dat*
  • boot.ini
  • bootmgr
  • bootnxt
  • desktop.ini
  • ntuser.dat
  • autorun.inf
  • ntldr
  • thumbs.db
  • bootsect.bak
  • bootfont.bin

It avoids encrypting files with the following strings in their file path:

  • *system volume information
  • *windows.old
  • *:\users\*\*temp.mp
  • *msocache
  • *:\winnt
  • *$windows.~ws
  • *perflogs
  • *boot
  • *:\windows
  • *:\program file*\vmware.e
  • \*\users\*\*temp.temp
  • \*\winnt.nt
  • \*\windows.ws
  • *\program file*\vmware.e
  • *appdata*microsoft
  • *appdata*packages
  • *microsoft\provisioning
  • *dvd maker
  • *Internet Explorer
  • *Mozilla
  • *Mozilla*
  • *Old Firefox data
  • *\program file*\windows media*.*
  • *\program file*\windows portable*.*
  • *windows defender
  • *\program file*\windows nt.t
  • *\program file*\windows photo*.*
  • *\program file*\windows side*.*
  • *\program file*\windowspowershell.l
  • *\program file*\cuass*.*
  • *\program file*\microsoft games.s
  • *\program file*\common files\system.em
  • *\program file*\common files\*shared.ed
  • *\program file*\common files\reference ass*.s*
  • *\windows\cache*.*
  • *temporary internet*
  • *media player
  • *:\users\*\appdata\*\microsoft.soft
  • \*\users\*\appdata\*\microsoft.rosoft
  • *\Program File*\Cisco.o

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

  • .{6 random characters}

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

  • {Encrypted Directory}\{Appended File Extension}-Readme.txt

It avoids encrypting files with the following file extensions:

  • .msp
  • .exe
  • .sys
  • .msc
  • .mod
  • .clb
  • .mui
  • .regtrans-ms
  • .theme
  • .hta
  • .shs
  • .nomedia
  • .diagpkg
  • .cab
  • .ics
  • .msstyles
  • .cur
  • .drv
  • .icns
  • .diagcfg
  • .dll
  • .ocx
  • .lnk
  • .ico
  • .idx
  • .ps1
  • .mpa
  • .cpl
  • .icl
  • .msu
  • .msi
  • .nls
  • .scr
  • .adv
  • .386
  • .com
  • .hlp
  • .rom
  • .lock
  • .386
  • .wpx
  • .ani
  • .prf
  • .rtp
  • .ldf
  • .key
  • .diagcab
  • .cmd
  • .spl
  • .deskthemepack
  • .bat
  • .themepack

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 16.526.05
FIRST VSAPI PATTERN DATE: 08 Feb 2021
VSAPI OPR PATTERN File: 16.527.00
VSAPI OPR PATTERN Date: 09 Feb 2021

Step 1

Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:

  • Troj.Win32.TRX.XXPE50FFF042

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 files

[ 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.
  • {Encrypted Directory}\{Appended File Extension}-Readme.txt

Step 5

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.NETWALKER.FKIQ. 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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