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Ransom.PS1.PROLOCK.AA

May 28, 2020
 Analysis by: Joshua Paul Ignacio
 ALIASES:

PwrSh:PowerSploit-D [Trj] (AVAST)

 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:

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:

2,720 bytes

Memory Resident:

No

Initial Samples Received Date:

19 Mar 2020

Payload:

Terminates processes, 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:

  • vssadmin.exe resize shadowstorage /for={Drive Letter}: /on={Drive Letter}: /maxsize=401MB → resizes the maximum amount of storage space that can be used for shadow copy storage
  • vssadmin.exe resize shadowstorage /for={Drive Letter}: /on={Drive Letter}: /maxsize=unbounded → resizes the maximum amount of storage space that can be used for shadow copy storage
  • vssadmin.exe delete shadows /all /quiet → deletes shadow copies

Process Termination

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

  • Acronis VSS Provider
  • AcronisAgent
  • Alerter
  • BackupExecAgentAccelerator
  • BackupExecDeviceMediaService
  • BackupExecJobEngine
  • BackupExecManagementService
  • BackupExecRPCService
  • BackupExecVSSProvider
  • BASupportExpressSrvcUpdater_N_Central
  • BASupportExpressStandaloneService_N_Central
  • bbagent
  • CSFalconService
  • DFSR
  • epag
  • EPIntegrationService
  • EPProtectedService
  • epredline
  • EPSecurityService
  • EPUpdateService
  • EqlReqService
  • EqlVss
  • hasplms
  • macmnsvc
  • masvc
  • MB3Service
  • MBAMService
  • MBEndpointAgent
  • McAfeeDLPAgentService
  • McAfeeFramework
  • mfemms
  • mozyprobackup
  • MsDtsServer
  • MSExchangeADTopology
  • MSExchangeDelivery
  • MSExchangeDiagnostics
  • MSExchangeEdgeSync
  • MSExchangeES
  • MSExchangeHM
  • MSExchangeHMRecovery
  • MSExchangeIS
  • MSExchangeMailboxReplication
  • MSExchangeMGMT
  • MSExchangeMTA
  • MSExchangeRepl
  • MSExchangeRPC
  • MSExchangeSA
  • MSExchangeServiceHost
  • MSExchangeSRS
  • MSExchangeTransport
  • MSExchangeUM
  • MSExchangeUMCR
  • MSMQ
  • MSOLAP$*
  • MSOLAP$SQL_2008
  • MSOLAP$SYSTEM_BGC
  • MSOLAP$TPS
  • MSOLAP$TPSAMA
  • MSSQL$*
  • MSSQL$BKUPEXEC
  • MSSQL$ECWDB2
  • MSSQL$PRACTICEMGT
  • MSSQL$PRACTTICEBGC
  • MSSQL$PROD
  • MSSQL$PROFXENGAGEMENT
  • MSSQL$SBSMONITORING
  • MSSQL$SHAREPOINT
  • MSSQL$SOPHOS
  • MSSQL$SQL_2008
  • MSSQL$SQLEXPRESS
  • MSSQL$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$TPSAMA
  • MSSQLSERVER
  • MSSQLServerADHelper
  • MSSQLServerADHelper100
  • MSSQLServerOLAPService
  • MySQL57
  • NasPmService
  • OracleClientCache80
  • OSearch15
  • psqlWGE
  • QuickBooksDB25
  • RapidRecoveryAgent
  • ReportServer
  • ReportServer$*
  • ReportServer$SQL_2008
  • ReportServer$SYSTEM_BGC
  • ReportServer$TPS
  • ReportServer$TPSAMA
  • SPAdminV4
  • SPSearchHostController
  • SPTraceV4
  • SPUserCodeV4
  • SPWriterV4
  • SQLAgent$*
  • SQLAgent$BKUPEXEC
  • SQLAgent$CITRIX_METAFRAME
  • SQLAgent$CXDB
  • SQLAgent$ECWDB2
  • SQLAgent$PRACTTICEBGC
  • SQLAgent$PRACTTICEMGT
  • SQLAgent$PROD
  • SQLAgent$PROFXENGAGEMENT
  • SQLAgent$SBSMONITORING
  • SQLAgent$SHAREPOINT
  • SQLAgent$SOPHOS
  • SQLAgent$SQL_2008
  • SQLAgent$SQLEXPRESS
  • SQLAgent$SYSTEM_BGC
  • SQLAgent$TPS
  • SQLAgent$TPSAMA
  • SQLAgent$VEEAMSQL2008R2
  • SQLAgent$VEEAMSQL2012
  • SQLBackupAgent
  • SQLBackups
  • SQLBrowser
  • SQLsafe Backup Service
  • SQLSafeOLRService
  • SQLSERVERAGENT
  • SQLTELEMETRY
  • SQLWriter
  • stc_endpt_svc
  • swprv
  • Symantec System Recovery
  • SyncoveryVSSService
  • TeamViewer
  • TMBMServer
  • tmccsf
  • tmlisten
  • Veeam Backup Catalog Data Service
  • VeeamBackupSvc
  • VeeamCatalogSvc
  • VeeamCloudSvc
  • VeeamEndpointBackupSvc
  • VeeamEnterpriseManagerSvc
  • VeeamMountSvc
  • VeeamNFSSvc
  • VeeamRESTSvc
  • VeeamTransportSvc
  • vhdsvc
  • VSNAPVSS
  • wbengine
  • WinVNC4
  • wsbexchange
  • YTBackup

Other Details

This Ransomware does the following:

  • It requires the following file in order to execute its malicious routines properly:
    • C:\Programdata\WinMgr.bmp → Detected as Ransom.Win32.PROLOCK.AA
  • It avoids encrypting files that are below 8KB in size.

Ransomware Routine

This Ransomware avoids encrypting files found in the following folders:

  • $Recycle.Bin
  • All Users
  • Boot
  • Common Files
  • DVD Maker
  • Internet Explorer
  • Kaspersky Lab
  • Kaspersky Lab Setup Files
  • Microsoft
  • Microsoft.NET
  • Microsoft_Corporation
  • Mozilla Firefox
  • PerfLog
  • System Volume Information
  • Uninstall Information
  • Windows
  • Windows Defender
  • Windows Mail
  • Windows Media Player
  • Windows NT
  • Windows Photo Viewer
  • Windows Portable Devices
  • Windows Sidebar
  • WindowsApps
  • WindowsPowerShell

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

  • .proLock

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

  • {Encrypted Directory}\[HOW TO RECOVER FILES].TXT

It avoids encrypting files with the following file extensions:

  • .bac
  • .bak
  • .bat
  • .bkf
  • .chm
  • .cmd
  • .dll
  • .dsk
  • .exe
  • .hlf
  • .ico
  • .inf
  • .ini
  • .lng
  • .lnk
  • .msi
  • .set
  • .sys
  • .ttf
  • .vhd
  • .wbc
  • .win

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.752.04

FIRST VSAPI PATTERN DATE:

19 Mar 2020

VSAPI OPR PATTERN File:

15.753.00

VSAPI OPR PATTERN Date:

20 Mar 2020

Step 1

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 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.PS1.PROLOCK.AA

[ 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.  
  • {Encrypted Directory}\\[HOW TO RECOVER FILES].TXT

Step 5

Scan your computer with your Trend Micro product to delete files detected as Ransom.PS1.PROLOCK.AA. 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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