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Ransom.Win32.MEDUSA.SM

September 26, 2023
 Analysis by: Raymart Christian Yambot
 ALIASES:

Win32:RansomX-gen [Ransom] (AVAST)

 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:

Downloaded from the Internet, Dropped by other malware


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 drops files as ransom note. It avoids encrypting files with the following file extensions.

  TECHNICAL DETAILS

File Size:

637,440 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

23 Sep 2023

Payload:

Disables AV, Encrypts files, Terminates processes, Deletes 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:

  • net stop "{Service name}" /y
  • taskkill /F /im {Process name} /T
  • vssadmin Delete Shadows /all /quiet
  • vssadmin resize shadowstorage /for={Drive letter} /on={Drive letter} /maxsize={Size in MB}
  • vssadmin resize shadowstorage /for={Drive letter} /on={Drive letter} /maxsize=unbounded
  • cmd /c ping localhost -n 3 > nul; & del {Malware Name}
  • powershell -executionpolicy bypass -File {Powershell script path}
  • powershell -Command "& {{Powershell script path}}"

Process Termination

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

  • via net stop:
    • Acronis VSS Provider
    • Enterprise Client Service
    • Sophos Agent
    • Sophos AutoUpdate Service
    • Sophos Clean Service
    • Sophos Device Control Service
    • Sophos File Scanner Service
    • Sophos Health Service
    • Sophos MCS Agent
    • Sophos MCS Client
    • Sophos Message Router
    • Sophos Safestore Service
    • Sophos System Protection Service
    • Sophos Web Control Service
    • SQLsafe Backup Service
    • SQLsafe Filter Service
    • Symantec System Recovery
    • Veeam Backup Catalog Data Service
    • AcronisAgent
    • AcrSch2Svc
    • Antivirus
    • ARSM
    • BackupExecAgentAccelerator
    • BackupExecAgentBrowser
    • BackupExecDeviceMediaService
    • BackupExecJobEngine
    • BackupExecManagementService
    • BackupExecRPCService
    • BackupExecVSSProvider
    • bedbg
    • fDCAgent
    • EPSecurityService
    • EPUpdateService
    • EraserSvc11710
    • EsgShKernel
    • FA_Scheduler
    • IISAdmin
    • IMAP4Svc
    • macmnsvc
    • masvc
    • MBAMService
    • MBEndpointAgent
    • McAfeeEngineService
    • McAfeeFramework
    • McAfeeFrameworkMcAfeeFramework
    • McShield
    • McTaskManager
    • mfemms
    • mfevtp
    • MMS
    • mozyprobackup
    • MsDtsServer
    • MsDtsServer100
    • MsDtsServer110
    • MSExchangeES
    • MSExchangeIS
    • MSExchangeMGMT
    • MSExchangeMTA
    • MSExchangeSA
    • MSExchangeSRS
    • MSOLAP$SQL_2008
    • MSOLAP$SYSTEM_BGC
    • MSOLAP$TPS
    • MSOLAP$TPSAMA
    • MSSQL$BKUPEXEC
    • MSSQL$ECWDB2
    • MSSQL$PRACTICEMGT
    • MSSQL$PRACTTICEBGC
    • MSSQL$PROFXENGAGEMENT
    • MSSQL$SBSMONITORING
    • MSSQL$SHAREPOINT
    • MSSQL$SQL_2008
    • MSSQL$SYSTEM_BGC
    • MSSQL$TPS
    • MSSQL$TPSAMA
    • MSSQL$VEEAMSQL2008R2
    • MSSQL$VEEAMSQL2012
    • MSSQLFDLauncher
    • MSSQLFDLauncher$PROFXENGAGEMENT
    • MSSQLFDLauncher$SBSMONITORING
    • MSSQLFDLauncher$SHAREPOINT
    • MSSQLFDLauncher$SQL_2008
    • MSSQLFDLauncher$SYSTEM_BGC
    • MSSQLFDLauncher$TPS
    • MSSQLFDLauncher$TPSAMA
    • MSSQLSERVER
    • MSSQLServerADHelper100
    • MSSQLServerOLAPService
    • MySQL80
    • MySQL57
    • ntrtscan
    • OracleClientCache80
    • PDVFSService
    • POP3Svc
    • ReportServer
    • ReportServer$SQL_2008
    • ReportServer$SYSTEM_BGC
    • ReportServer$TPS
    • ReportServer$TPSAMA
    • RESvc
    • sacsvr
    • SamSs
    • SAVAdminService
    • SAVService
    • SDRSVC
    • SepMasterService
    • ShMonitor
    • Smcinst
    • SmcService
    • SMTPSvc
    • SNAC
    • SntpService
    • sophossps
    • SQLAgent$BKUPEXEC
    • SQLAgent$ECWDB2
    • SQLAgent$PRACTTICEBGC
    • SQLAgent$PRACTTICEMGT
    • SQLAgent$PROFXENGAGEMENT
    • SQLAgent$SBSMONITORING
    • SQLAgent$SHAREPOINT
    • SQLAgent$SQL_2008
    • SQLAgent$SYSTEM_BGC
    • SQLAgent$TPS
    • SQLAgent$TPSAMA
    • SQLAgent$VEEAMSQL2008R2
    • SQLAgent$VEEAMSQL2012
    • SQLBrowser
    • SQLSafeOLRService
    • SQLSERVERAGENT
    • SQLTELEMETRY
    • SQLTELEMETRY$ECWDB2
    • SQLWriter
    • SstpSvc
    • svcGenericHost
    • swi_filter
    • swi_service
    • swi_update_64
    • TmCCSF
    • tmlisten
    • TrueKey
    • TrueKeyScheduler
    • TrueKeyServiceHelper
    • UI0Detect
    • VeeamBackupSvc
    • VeeamBrokerSvc
    • VeeamCatalogSvc
    • VeeamCloudSvc
    • VeeamDeploymentService
    • VeeamDeploySvc
    • VeeamEnterpriseManagerSvc
    • VeeamMountSvc
    • VeeamNFSSvc
    • VeeamRESTSvc
    • VeeamTransportSvc
    • W3Svc
    • wbengine
    • WRSVC
    • MSSQL$VEEAMSQL2008R2
    • SQLAgent$VEEAMSQL2008R2
    • VeeamHvIntegrationSvc
    • swi_update
    • SQLAgent$CXDB
    • SQLAgent$CITRIX_METAFRAME
    • SQL Backups
    • MSSQL$PROD
    • Zoolz 2 Service
    • MSSQLServerADHelper
    • SQLAgent$PROD
    • msftesql$PROD
    • NetMsmqActivator
    • EhttpSrv
    • ekrn
    • ESHASRV
    • MSSQL$SOPHOS
    • SQLAgent$SOPHOS
    • AVP
    • klnagent
    • MSSQL$SQLEXPRESS
    • SQLAgent$SQLEXPRESS
    • wbengine
    • kavfsslp
    • KAVFSGT
    • KAVFS
    • mfefire

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

  • via taskkill /F /im:
    • zoolz.exe
    • agntsvc.exe
    • dbeng50.exe
    • dbsnmp.exe
    • encsvc.exe
    • excel.exe
    • firefoxconfig.exe
    • infopath.exe
    • isqlplussvc.exe
    • msaccess.exe
    • msftesql.exe
    • mspub.exe
    • mydesktopqos.exe
    • mydesktopservice.exe
    • mysqld.exe
    • mysqld-nt.exe
    • mysqld-opt.exe
    • ocautoupds.exe
    • ocomm.exe
    • ocssd.exe
    • onenote.exe
    • oracle.exe
    • outlook.exe
    • powerpnt.exe
    • sqbcoreservice.exe
    • sqlagent.exe
    • sqlbrowser.exe
    • sqlservr.exe
    • sqlwriter.exe
    • steam.exe
    • synctime.exe
    • tbirdconfig.exe
    • thebat.exe
    • thebat64.exe
    • thunderbird.exe
    • visio.exe
    • winword.exe
    • wordpad.exe
    • xfssvccon.exe
    • tmlisten.exe
    • PccNTMon.exe
    • CNTAoSMgr.exe
    • Ntrtscan.exe
    • mbamtray.exe

Other Details

This Ransomware does the following:

  • Creates an anonymous pipe.
  • It shows its logs within the command prompt:

  • It deletes itself after execution.
  • It encrypts fixed, removable and network drives.

It accepts the following parameters:

  • -V → Displays the Medusa ransomware version
  • -d → Will not delete itslef after execution
  • -f → Exclude system folder from encryption
  • -i {File path} → Encrypts specified folder
  • -k {File path} → Loads key from the mentioned file
  • -n → Uses network drives
  • -p → Skips preprocess routine(preprocess: termination of processes and services, and deletion of shadow copy)
  • -s → Excludes system drive from encryption
  • -t {File path} → Changes the content of the ransom note stated in the file path
  • -v → Show console window
  • -w {File path} → Executes the powershell command
  • -x {File path} → Avoid strings mentioned in the file path

Ransomware Routine

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

  • \Windows\
  • \Windows.old\
  • \PerfLogs\
  • \MSOCache\
  • Program Files
  • Program Files (x86)
  • ProgramData

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

  • .MEDUSA

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

  • {Encrypted directory}\!!READ_ME_MEDUSA!!.txt
  • %Desktop%\!!READ_ME_MEDUSA!!.txt

It avoids encrypting files with the following file extensions:

  • .dll
  • .exe
  • .lnk
  • .MEDUSA

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

18.314.08

FIRST VSAPI PATTERN DATE:

15 Mar 2023

VSAPI OPR PATTERN File:

18.315.00

VSAPI OPR PATTERN Date:

16 Mar 2023

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.XXPE50FFF073

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}\!!READ_ME_MEDUSA!!.txt
  • %Desktop%\!!READ_ME_MEDUSA!!.txt

Step 5

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.MEDUSA.SM. 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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