Analysis

  • max time kernel
    102s
  • max time network
    157s
  • platform
    windows7_x64
  • resource
    win7-20220414-en
  • submitted
    07/07/2022, 17:24

General

  • Target
    DCRatBuild_Full.exe
  • Size 2.5MB
  • Sample220707-vypebseee3
  • SHA256 dccd3eab40a7320e2d30eabd3bdb5ee0ba29d16176e73f4adf34e3158d50eef8
  • MD5 SHA1 SHA512

Malware Config

Signatures

  • DcRat 17 IoCs

    DarkCrystal(DC) is a new .NET RAT active since June 2019 capable of loading additional plugins.

  • Modifies WinLogon for persistence 2 TTPs 5 IoCs
  • Process spawned unexpected child process 15 IoCs

    This typically indicates the parent process was compromised via an exploit or macro.

  • suricata: ET MALWARE DCRAT Activity (GET)

    suricata: ET MALWARE DCRAT Activity (GET)

  • DCRat payload 8 IoCs

    Detects payload of DCRat, commonly dropped by NSIS installers.

  • Disables Task Manager via registry modification
  • Executes dropped EXE 2 IoCs
  • Loads dropped DLL 2 IoCs
  • Adds Run key to start application 2 TTPs 10 IoCs
  • Drops file in Program Files directory 7 IoCs
  • Enumerates physical storage devices 1 TTPs

    Attempts to interact with connected storage/optical drive(s). Likely ransomware behaviour.

  • Creates scheduled task(s) 1 TTPs 15 IoCs

    Schtasks is often used by malware for persistence or to perform post-infection execution.

  • Modifies registry key 1 TTPs 1 IoCs
  • Suspicious behavior: EnumeratesProcesses 10 IoCs
  • Suspicious use of AdjustPrivilegeToken 2 IoCs
  • Suspicious use of WriteProcessMemory 23 IoCs

Processes

  • C:\Users\Admin\AppData\Local\Temp\DCRatBuild_Full.exe
    "C:\Users\Admin\AppData\Local\Temp\DCRatBuild_Full.exe"
    1⤵
    • Suspicious use of WriteProcessMemory
    PID:1672
    • C:\Windows\SysWOW64\WScript.exe
      "C:\Windows\System32\WScript.exe" "C:\Users\Admin\AppData\Local\Temp\blockrefCommon\f3eALabGJmbx2bkCsBaU.vbe"
      2⤵
      • Suspicious use of WriteProcessMemory
      PID:876
      • C:\Windows\SysWOW64\cmd.exe
        cmd /c ""C:\Users\Admin\AppData\Local\Temp\blockrefCommon\P9UyGj8fNPESmY.bat" "
        3⤵
        • Loads dropped DLL
        • Suspicious use of WriteProcessMemory
        PID:1296
        • C:\Users\Admin\AppData\Local\Temp\blockrefCommon\Portsurrogatehost.exe
          "C:\Users\Admin\AppData\Local\Temp\blockrefCommon\Portsurrogatehost.exe"
          4⤵
          • DcRat
          • Modifies WinLogon for persistence
          • Executes dropped EXE
          • Adds Run key to start application
          • Drops file in Program Files directory
          • Suspicious behavior: EnumeratesProcesses
          • Suspicious use of AdjustPrivilegeToken
          • Suspicious use of WriteProcessMemory
          PID:2044
          • C:\Users\All Users\Adobe\Acrobat\csrss.exe
            "C:\Users\All Users\Adobe\Acrobat\csrss.exe"
            5⤵
            • Executes dropped EXE
            • Suspicious behavior: EnumeratesProcesses
            • Suspicious use of AdjustPrivilegeToken
            PID:1300
        • C:\Windows\SysWOW64\reg.exe
          reg add HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System /v DisableTaskMgr /t REG_DWORD /d 1 /f
          4⤵
          • Modifies registry key
          PID:1396
    • C:\Windows\SysWOW64\WScript.exe
      "C:\Windows\System32\WScript.exe" "C:\Users\Admin\AppData\Local\Temp\blockrefCommon\file.vbs"
      2⤵
        PID:1988
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "lsassl" /sc MINUTE /mo 7 /tr "'C:\Program Files (x86)\Microsoft.NET\Primary Interop Assemblies\lsass.exe'" /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:1880
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "lsass" /sc ONLOGON /tr "'C:\Program Files (x86)\Microsoft.NET\Primary Interop Assemblies\lsass.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:1636
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "lsassl" /sc MINUTE /mo 6 /tr "'C:\Program Files (x86)\Microsoft.NET\Primary Interop Assemblies\lsass.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:1776
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "wininitw" /sc MINUTE /mo 14 /tr "'C:\Program Files\Java\wininit.exe'" /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:2020
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "wininit" /sc ONLOGON /tr "'C:\Program Files\Java\wininit.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:1628
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "wininitw" /sc MINUTE /mo 5 /tr "'C:\Program Files\Java\wininit.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:1372
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "smsss" /sc MINUTE /mo 13 /tr "'C:\Program Files\Windows Journal\it-IT\smss.exe'" /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:1512
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "smss" /sc ONLOGON /tr "'C:\Program Files\Windows Journal\it-IT\smss.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:1112
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "smsss" /sc MINUTE /mo 6 /tr "'C:\Program Files\Windows Journal\it-IT\smss.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:1548
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "csrssc" /sc MINUTE /mo 13 /tr "'C:\Users\All Users\Adobe\Acrobat\csrss.exe'" /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:976
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "csrss" /sc ONLOGON /tr "'C:\Users\All Users\Adobe\Acrobat\csrss.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:1376
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "csrssc" /sc MINUTE /mo 12 /tr "'C:\Users\All Users\Adobe\Acrobat\csrss.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:1752
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "winlogonw" /sc MINUTE /mo 9 /tr "'C:\Recovery\3ca42062-bc30-11ec-af8e-f2122c6314cc\winlogon.exe'" /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:1324
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "winlogon" /sc ONLOGON /tr "'C:\Recovery\3ca42062-bc30-11ec-af8e-f2122c6314cc\winlogon.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:1624
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "winlogonw" /sc MINUTE /mo 9 /tr "'C:\Recovery\3ca42062-bc30-11ec-af8e-f2122c6314cc\winlogon.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:1284

    Network

          MITRE ATT&CK Enterprise v6

          Replay Monitor

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          Downloads

          csrss.exe

          • Path C:\ProgramData\Adobe\Acrobat\csrss.exe
          • Size 2.2MB
          • SHA256 1aa5b51d990d7a1a56b5a4181678633fbe02c77154f2fcd865f670b5fafc8612
          • MD5 SHA1 SHA512 SSDEEP

          P9UyGj8fNPESmY.bat

          • Path C:\Users\Admin\AppData\Local\Temp\blockrefCommon\P9UyGj8fNPESmY.bat
          • Size 157B
          • SHA256 eecd17242cee9f4812a9e61f189e4c43c78c595690e72a937d8287dce5563cb9
          • MD5 SHA1 SHA512

          Portsurrogatehost.exe

          • Path C:\Users\Admin\AppData\Local\Temp\blockrefCommon\Portsurrogatehost.exe
          • Size 2.2MB
          • SHA256 1aa5b51d990d7a1a56b5a4181678633fbe02c77154f2fcd865f670b5fafc8612
          • MD5 SHA1 SHA512 SSDEEP

          Portsurrogatehost.exe

          • Path C:\Users\Admin\AppData\Local\Temp\blockrefCommon\Portsurrogatehost.exe
          • Size 2.2MB
          • SHA256 1aa5b51d990d7a1a56b5a4181678633fbe02c77154f2fcd865f670b5fafc8612
          • MD5 SHA1 SHA512 SSDEEP

          f3eALabGJmbx2bkCsBaU.vbe

          • Path C:\Users\Admin\AppData\Local\Temp\blockrefCommon\f3eALabGJmbx2bkCsBaU.vbe
          • Size 209B
          • SHA256 3916307bef91035d352655d3110d533904e3946c309c3497e35096e7156f0136
          • MD5 SHA1 SHA512

          file.vbs

          • Path C:\Users\Admin\AppData\Local\Temp\blockrefCommon\file.vbs
          • Size 34B
          • SHA256 f1cccb5ae4aa51d293bd3c7d2a1a04cb7847d22c5db8e05ac64e9a6d7455aa0b
          • MD5 SHA1 SHA512

          csrss.exe

          • Path C:\Users\All Users\Adobe\Acrobat\csrss.exe
          • Size 2.2MB
          • SHA256 1aa5b51d990d7a1a56b5a4181678633fbe02c77154f2fcd865f670b5fafc8612
          • MD5 SHA1 SHA512 SSDEEP

          Portsurrogatehost.exe

          • Path \Users\Admin\AppData\Local\Temp\blockrefCommon\Portsurrogatehost.exe
          • Size 2.2MB
          • SHA256 1aa5b51d990d7a1a56b5a4181678633fbe02c77154f2fcd865f670b5fafc8612
          • MD5 SHA1 SHA512 SSDEEP

          Portsurrogatehost.exe

          • Path \Users\Admin\AppData\Local\Temp\blockrefCommon\Portsurrogatehost.exe
          • Size 2.2MB
          • SHA256 1aa5b51d990d7a1a56b5a4181678633fbe02c77154f2fcd865f670b5fafc8612
          • MD5 SHA1 SHA512 SSDEEP

          memory/1300-80-0x0000000000390000-0x00000000003E6000-memory.dmp

          memory/1300-78-0x0000000000D20000-0x0000000000F64000-memory.dmp

          memory/1672-54-0x0000000075AE1000-0x0000000075AE3000-memory.dmp

          memory/2044-68-0x00000000000A0000-0x00000000002E4000-memory.dmp

          memory/2044-74-0x0000000000830000-0x0000000000838000-memory.dmp

          memory/2044-73-0x0000000000820000-0x000000000082E000-memory.dmp

          memory/2044-72-0x00000000007F0000-0x0000000000802000-memory.dmp

          memory/2044-71-0x00000000007A0000-0x00000000007F6000-memory.dmp

          memory/2044-70-0x0000000000790000-0x00000000007A0000-memory.dmp

          memory/2044-69-0x0000000000770000-0x000000000078C000-memory.dmp