Analysis

  • max time kernel
    5s
  • max time network
    25s
  • platform
    windows10-2004_x64
  • resource
    win10v2004-20240802-en
  • resource tags

    arch:x64arch:x86image:win10v2004-20240802-enlocale:en-usos:windows10-2004-x64system
  • submitted
    17-09-2024 02:23

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 (2990) files with added filename extension

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

  • Enumerates connected drives 3 TTPs 1 IoCs

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

  • 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 2 IoCs
  • Suspicious use of AdjustPrivilegeToken 22 IoCs
  • Suspicious use of WriteProcessMemory 20 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⤵
    • 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:4520
    • C:\Windows\SYSTEM32\cmd.exe
      cmd /c wmic shadowcopy delete /nointeractive
      2⤵
      • Suspicious use of WriteProcessMemory
      PID:2900
      • C:\Windows\System32\Wbem\WMIC.exe
        wmic shadowcopy delete /nointeractive
        3⤵
        • Suspicious use of AdjustPrivilegeToken
        PID:5604
    • C:\Windows\SYSTEM32\cmd.exe
      cmd /c vssadmin.exe Delete Shadows /All /Quiet
      2⤵
      • Suspicious use of WriteProcessMemory
      PID:4884
      • C:\Windows\system32\vssadmin.exe
        vssadmin.exe Delete Shadows /All /Quiet
        3⤵
        • Interacts with shadow copies
        PID:39144
    • C:\Windows\SYSTEM32\cmd.exe
      cmd /c bcdedit /set {default} recoveryenabled No
      2⤵
      • Suspicious use of WriteProcessMemory
      PID:4052
      • C:\Windows\system32\bcdedit.exe
        bcdedit /set {default} recoveryenabled No
        3⤵
        • Modifies boot configuration data using bcdedit
        PID:39152
    • C:\Windows\SYSTEM32\cmd.exe
      cmd /c bcdedit /set {default} bootstatuspolicy ignoreallfailures
      2⤵
      • Suspicious use of WriteProcessMemory
      PID:2284
      • C:\Windows\system32\bcdedit.exe
        bcdedit /set {default} bootstatuspolicy ignoreallfailures
        3⤵
        • Modifies boot configuration data using bcdedit
        PID:39160
    • C:\Windows\SYSTEM32\cmd.exe
      cmd /c powershell -command "Get-EventLog -LogName * | ForEach { Clear-EventLog $_.Log }"
      2⤵
      • Suspicious use of WriteProcessMemory
      PID:4092
      • C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
        powershell -command "Get-EventLog -LogName * | ForEach { Clear-EventLog $_.Log }"
        3⤵
        • Command and Scripting Interpreter: PowerShell
        PID:5536
    • C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
      powershell -Command "$a = [System.IO.File]::ReadAllText(\"C:\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
      PID:36700
      • 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\1137146776.png /f
        3⤵
          PID:36344
        • C:\Windows\system32\rundll32.exe
          "C:\Windows\system32\rundll32.exe" user32.dll UpdatePerUserSystemParameters 0 False
          3⤵
            PID:36284
      • C:\Windows\system32\vssvc.exe
        C:\Windows\system32\vssvc.exe
        1⤵
          PID:14160

        Network

        MITRE ATT&CK Enterprise v15

        Replay Monitor

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        Downloads

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

          Filesize

          2KB

          MD5

          6cf293cb4d80be23433eecf74ddb5503

          SHA1

          24fe4752df102c2ef492954d6b046cb5512ad408

          SHA256

          b1f292b6199aa29c7fafbca007e5f9e3f68edcbbca1965bc828cc92dc0f18bb8

          SHA512

          0f91e2da0da8794b9797c7b50eb5dfd27bde4546ceb6902a776664ce887dd6f12a0dd8773d612ccc76dfd029cd280778a0f0ae17ce679b3d2ffd968dd7e94a00

        • C:\Users\Admin\AppData\Local\Microsoft\Windows\PowerShell\StartupProfileData-NonInteractive

          Filesize

          1KB

          MD5

          c8861299853606fac3016094fcb76d2e

          SHA1

          8969dfdc86ceceb91bec0956f6a672a8606bc841

          SHA256

          07b966f55b6c7b2f633c7a4ace5c3cc0fc6f6dcbea8ff0da2210ed4a34c2cdf0

          SHA512

          841ca021eb2e9cb9831c2637f97739b0f2b35919b4e7eea3e39af808564f06b1d2175d618912603d1f61b364882c626799f68e069b13224d5db920ac7a267ef3

        • C:\Users\Admin\AppData\Local\Temp\__PSScriptPolicyTest_abhqqv5o.sfo.ps1

          Filesize

          60B

          MD5

          d17fe0a3f47be24a6453e9ef58c94641

          SHA1

          6ab83620379fc69f80c0242105ddffd7d98d5d9d

          SHA256

          96ad1146eb96877eab5942ae0736b82d8b5e2039a80d3d6932665c1a4c87dcf7

          SHA512

          5b592e58f26c264604f98f6aa12860758ce606d1c63220736cf0c779e4e18e3cec8706930a16c38b20161754d1017d1657d35258e58ca22b18f5b232880dec82

        • F:\GET_YOUR_FILES_BACK.txt

          Filesize

          1011B

          MD5

          01188d22b1675e3437b1418e14f4ffab

          SHA1

          6e7127f3bbfce49485ed8f1acf8f697bcb952818

          SHA256

          e4b3ac00a0b2eb195b26abffbc4368077384e73393e51605edda17dae05ab7f2

          SHA512

          6903ae3247f32ad79c60a2062cd6a7bdbf5a7c9db1bdc43bdbef4da3396945014d30968ea4c8531a2d0c7b695f1ea36e2b8c51bb39cc6157c4096ac04a6e187d

        • memory/5536-17744-0x000001521F770000-0x000001521F792000-memory.dmp

          Filesize

          136KB