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FortiGuard Labs is aware that a joint Cybersecurity Advisory (CSA) on MedusaLocker ransomware was released by the Federal Bureau of Investigation (FBI), the Cybersecurity and Infrastructure Security Agency (CISA), the Department of the Treasury, and the Financial Crimes Enforcement Network (FinCEN). MedusaLocker infection typically occurs through Remote Desktop Protocol (RDP) compromise, propagates MedusaLocker throughout the network, and uses AES-256 encryption to encrypt files.Why is this Significant?This is significant as the joint Cybersecurity Advisory (CSA) is the latest #StopRansomware advisory released by the Federal Bureau of Investigation (FBI), the Cybersecurity and Infrastructure Security Agency (CISA), the Department of the Treasury, and the Financial Crimes Enforcement Network (FinCEN), which provides observed tactics, techniques, and procedures (TTPs) and indicators of compromise (IOCs) to help organizations protect against ransomware.What is MedusaLocker Ransomware?MedusaLocker is a ransomware that encrypts files in the compromised machines with the AES-256 encryption algorithm and demands victims to pay a ransom in order to recover the affected files. According to the advisory, MedusaLocker primarily takes advantage of an insecure RDP configuration as an initial infection vector, however email spam and malicious attachments are also used.The advisory also states that MedusaLocker ransomware uses multiple infection processes:Uses a batch file to execute PowerShell script, which propagates the ransomware throughout the network. Restarts the LanmanWorkstation service, which allows registry edits to take effect. Kills the processes belonging to well-known security, accounting, and forensic software. Restarts the machine in safe mode.Encrypts files in the compromised machines with the AES-256 encryption algorithmRuns every 60 seconds, encrypting all files except those critical to the functionality of the victim’s machine and those that have the designated encrypted file extension. Establishes persistence by copying an executable (svhost.exe or svhostt.exe) to the %APPDATA%Roaming directory and scheduling a task to run the ransomware every 15 minutes. Attempts to prevent standard recovery techniques by deleting local backups, disabling startup recovery options, and deleting shadow copies.Leaves a ransom note into every folder containing instruction on how to reach out to the attacker either via MedusaLocker’s Tor sites or emails.The following is a list of known file extensions that MedusaLocker adds to the encrypts files:.1btc.bec.cn.datalock.deadfilesgr.decrypme.encrypted.faratak.FartingGiraffeAttacks.fileslock.fileslocked.jpz.nz.key1.lock.lockdata7.lockfiles.lockfilesUS.marlock01.marlock02.marlock08.marlock11.marlock13.marlock25.marlock6.marlock011.matlock20.mylock.newware.NET1.NZ.perfection.Readinstruction.READINSTRUCTION.ReadInstructions.readinstructions.rs.skynet.stopflies.tyco.tyco.uslockhh.uslockhh.zoomzoomn.exent_lock20.networkmaze.VinDizelPux.EG.support.deadfiles.readtheinstructions.lr.divsouth.lockfilesCO.lockfilesKR.EMPg296LCKThe following is a list of known MedusaLocker’s ransom notes:! _HOW_RECOVERY_FILES _!. HTML!!!HOW_TO_DECRYPT!!!how_to_ recover_data.html HOW_TO_OPEN_FILES.htmlHOW_TO_RECOVER_DATA.htmlhow_to_recover_data.html.marlock01How_to_recovery.txtinstructions.html READINSTRUCTION.html readinstructions.html readme_to_recover_filesrecovery_instruction.htmlrecovery_instructions.html What is the Status of Coverage?FortiGuard Labs provides the following AV coverage against known samples of MedusaLocker ransomware:W32/MedusaLocker.0FEB!trW32/MedusaLocker.9106!tr.ransomW32/MedusaLocker.C!tr.ransomW32/Ransom_Win32_MEDUSALOCKER.SMTHW32/Ransom_Win32_MEDUSALOCKER.SMTH!trW32/Ransom_Win32_MEDUSALOCKER.SMTH!tr.ransomW32/DelShad.BMQ!tr.ransomW32/Filecoder.FV!trW32/Filecoder.NSF!tr.ransomW32/Filecoder.NYA!tr.ransomW32/Generic.AC.171!trW32/Generik.DGWKQJO!trW32/Kryptik.HFBI!trW32/PossibleThreatW32/Ransomware.GUN!trW32/Zudochka.VHO!tr.ransomW64/Filecoder.DF!tr.ransomPossibleThreat.FAIRiskware/DelShad
