Analysis

  • max time kernel
    130s
  • max time network
    156s
  • platform
    windows10-2004_x64
  • resource
    win10v2004-en-20220113
  • submitted
    23-03-2022 21:00

General

Malware Config

Signatures

  • DcRat 21 IoCs

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

  • Process spawned unexpected child process 12 IoCs

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

  • UAC bypass 3 TTPs
  • suricata: ET MALWARE DCRAT Activity (GET)

    suricata: ET MALWARE DCRAT Activity (GET)

  • Executes dropped EXE 1 IoCs
  • Checks computer location settings 2 TTPs 2 IoCs

    Looks up country code configured in the registry, likely geofence.

  • Adds Run key to start application 2 TTPs 12 IoCs
  • Checks whether UAC is enabled 1 TTPs 6 IoCs
  • Drops file in System32 directory 15 IoCs
  • Drops file in Program Files directory 2 IoCs
  • Drops file in Windows directory 4 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 12 IoCs

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

  • Modifies registry class 1 IoCs
  • Suspicious behavior: EnumeratesProcesses 9 IoCs
  • Suspicious use of AdjustPrivilegeToken 3 IoCs
  • Suspicious use of WriteProcessMemory 8 IoCs
  • System policy modification 1 TTPs 9 IoCs

Processes

  • C:\Users\Admin\AppData\Local\Temp\6.exe
    "C:\Users\Admin\AppData\Local\Temp\6.exe"
    1⤵
    • DcRat
    • Checks computer location settings
    • Adds Run key to start application
    • Checks whether UAC is enabled
    • Drops file in System32 directory
    • Drops file in Windows directory
    • Modifies registry class
    • Suspicious behavior: EnumeratesProcesses
    • Suspicious use of AdjustPrivilegeToken
    • Suspicious use of WriteProcessMemory
    • System policy modification
    PID:1160
    • C:\Windows\System32\cmd.exe
      "C:\Windows\System32\cmd.exe" /C "C:\Users\Admin\AppData\Local\Temp\YhJtA5Z5n3.bat"
      2⤵
      • Suspicious use of WriteProcessMemory
      PID:4808
      • C:\Windows\system32\w32tm.exe
        w32tm /stripchart /computer:localhost /period:5 /dataonly /samples:2
        3⤵
          PID:3736
        • C:\Users\Admin\AppData\Local\Temp\6.exe
          "C:\Users\Admin\AppData\Local\Temp\6.exe"
          3⤵
          • Checks computer location settings
          • Adds Run key to start application
          • Checks whether UAC is enabled
          • Drops file in Program Files directory
          • Drops file in Windows directory
          • Suspicious behavior: EnumeratesProcesses
          • Suspicious use of AdjustPrivilegeToken
          • Suspicious use of WriteProcessMemory
          • System policy modification
          PID:4352
          • C:\Documents and Settings\winlogon.exe
            "C:\Documents and Settings\winlogon.exe"
            4⤵
            • Executes dropped EXE
            • Checks whether UAC is enabled
            • Suspicious behavior: EnumeratesProcesses
            • Suspicious use of AdjustPrivilegeToken
            • System policy modification
            PID:2988
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "dwm" /sc ONLOGON /tr "'C:\Windows\System32\gdi32full\dwm.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:5000
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "sihost" /sc ONLOGON /tr "'C:\Windows\System32\GenValObj\sihost.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:4468
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "dwm" /sc ONLOGON /tr "'C:\Windows\System32\ImplatSetup\dwm.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:4476
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "taskhostw" /sc ONLOGON /tr "'C:\Windows\System32\drvstore\taskhostw.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:3904
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "dwm" /sc ONLOGON /tr "'C:\Windows\System32\mfc120chs\dwm.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:436
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "fontdrvhost" /sc ONLOGON /tr "'C:\Windows\System32\WorkfoldersControl\fontdrvhost.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:3672
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "StartMenuExperienceHost" /sc ONLOGON /tr "'C:\Windows\SystemApps\Microsoft.Windows.StartMenuExperienceHost_cw5n1h2txyewy\AppxBlockMap\StartMenuExperienceHost.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:5080
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "taskhostw" /sc ONLOGON /tr "'C:\Windows\System32\srm\taskhostw.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:1440
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "RuntimeBroker" /sc ONLOGON /tr "'C:\ProgramData\Package Cache\{B175520C-86A2-35A7-8619-86DC379688B9}v11.0.61030\packages\vcRuntimeAdditional_x86\RuntimeBroker.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:1516
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "winlogon" /sc ONLOGON /tr "'C:\Documents and Settings\winlogon.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:2184
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "explorer" /sc ONLOGON /tr "'C:\Windows\bootstat\explorer.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:1688
    • C:\Windows\system32\schtasks.exe
      schtasks.exe /create /tn "explorer" /sc ONLOGON /tr "'C:\Program Files (x86)\Google\Policies\explorer.exe'" /rl HIGHEST /f
      1⤵
      • DcRat
      • Process spawned unexpected child process
      • Creates scheduled task(s)
      PID:2920

    Network

    MITRE ATT&CK Matrix ATT&CK v6

    Execution

    Scheduled Task

    1
    T1053

    Persistence

    Registry Run Keys / Startup Folder

    1
    T1060

    Scheduled Task

    1
    T1053

    Privilege Escalation

    Bypass User Account Control

    1
    T1088

    Scheduled Task

    1
    T1053

    Defense Evasion

    Bypass User Account Control

    1
    T1088

    Disabling Security Tools

    1
    T1089

    Modify Registry

    3
    T1112

    Discovery

    Query Registry

    1
    T1012

    System Information Discovery

    3
    T1082

    Replay Monitor

    Loading Replay Monitor...

    Downloads

    • C:\Documents and Settings\winlogon.exe
      Filesize

      564KB

      MD5

      748a4bea8c0624a4c7a69f67263e0839

      SHA1

      6955b7d516df38992ac6bff9d0b0f5df150df859

      SHA256

      220d8f8ff82d413c81bd02dfa001e1c478e8fbea44bad24f21b3a5284e15632e

      SHA512

      5fcdfddce3cc2e636001ed08c5f2f7590aadaa37c091f7ba94e519d298e284362721f1859c6ffbf064ae23e05d4e0e9754b515396812fbe9f9028497396799fd

    • C:\Users\Admin\AppData\Local\Microsoft\CLR_v4.0\UsageLogs\6.exe.log
      Filesize

      1KB

      MD5

      b7c0c43fc7804baaa7dc87152cdc9554

      SHA1

      1bab62bd56af745678d4e967d91e1ccfdeed4038

      SHA256

      46386a61f3aaf1b1c2e6efc9fc7e9e9ff16cd13ae58b8d856835771fedb6d457

      SHA512

      9fda3dd00a3406137e0113f13f78e77b20a76512b35820d38df696842cbbf2e2ebabfb99a3846c9637ecb54af858ec1551521187e379872973006426a253f769

    • C:\Users\Admin\AppData\Local\Temp\YhJtA5Z5n3.bat
      Filesize

      203B

      MD5

      1d1523baa7f95f99f056551c38538d8b

      SHA1

      a02089b0cd2fb7f6308eddb35437c117b4194e07

      SHA256

      cb5094fe8d71624397c5fae8831bc3103e468c5b17c383245fa5d16226b5776c

      SHA512

      ea33e3ae876ae4cb6447d485aea54c90bf81f01e619e35805a58548532ced360f88793d1cb5b40cefea39498dab29a4c60c6a4a802d10aa2018639af3a321527

    • C:\Users\winlogon.exe
      Filesize

      564KB

      MD5

      748a4bea8c0624a4c7a69f67263e0839

      SHA1

      6955b7d516df38992ac6bff9d0b0f5df150df859

      SHA256

      220d8f8ff82d413c81bd02dfa001e1c478e8fbea44bad24f21b3a5284e15632e

      SHA512

      5fcdfddce3cc2e636001ed08c5f2f7590aadaa37c091f7ba94e519d298e284362721f1859c6ffbf064ae23e05d4e0e9754b515396812fbe9f9028497396799fd

    • memory/1160-131-0x00007FFE67680000-0x00007FFE68141000-memory.dmp
      Filesize

      10.8MB

    • memory/1160-132-0x0000000002C90000-0x0000000002C92000-memory.dmp
      Filesize

      8KB

    • memory/1160-130-0x0000000000B40000-0x0000000000BD4000-memory.dmp
      Filesize

      592KB

    • memory/2988-144-0x000000001BBB0000-0x000000001BBB2000-memory.dmp
      Filesize

      8KB

    • memory/2988-143-0x00007FFE67330000-0x00007FFE67DF1000-memory.dmp
      Filesize

      10.8MB

    • memory/2988-140-0x0000000000000000-mapping.dmp
    • memory/3736-135-0x0000000000000000-mapping.dmp
    • memory/4352-138-0x00007FFE67330000-0x00007FFE67DF1000-memory.dmp
      Filesize

      10.8MB

    • memory/4352-139-0x000000001B220000-0x000000001B222000-memory.dmp
      Filesize

      8KB

    • memory/4352-136-0x0000000000000000-mapping.dmp
    • memory/4808-133-0x0000000000000000-mapping.dmp