Analysis

  • max time kernel
    1690s
  • max time network
    1792s
  • platform
    windows10-1703_x64
  • resource
    win10-20240214-en
  • resource tags

    arch:x64arch:x86image:win10-20240214-enlocale:en-usos:windows10-1703-x64system
  • submitted
    31/03/2024, 00:40

General

  • Target
    Client-built.exe
  • Size 3.1MB
  • Sample240331-a1mnasae4s
  • SHA256 f2e04196e1353ad216e077e0aeb2e1ab8ee93b8b16b205422b4cc6d8adc50cc2
  • MD5 SHA1 SHA512 SSDEEP

Malware Config

Extracted

Family
  • quasar

Version
  • 1.4.1

Botnet
  • Ratted

C2
  • 140.238.91.110:44867

Mutex
  • be049c71-d631-4f68-8b3e-8e01081f2340

Attributes
  • encryption_key

    AA883CE7347A3543F81EBCDE3BBF3BFC9C60344E

  • install_name

    WOS64UPD.exe

  • log_directory

    Windows Update Logs

  • reconnect_delay

    3000

  • startup_key

    Windows Updater

  • subdirectory

    Windows

Signatures

  • Quasar RAT

    Quasar is an open source Remote Access Tool.

  • Quasar payload 2 IoCs
  • Executes dropped EXE 1 IoCs
  • Creates scheduled task(s) 1 TTPs 2 IoCs

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

  • Suspicious use of AdjustPrivilegeToken 2 IoCs
  • Suspicious use of SetWindowsHookEx 1 IoCs
  • Suspicious use of WriteProcessMemory 6 IoCs
  • Uses Task Scheduler COM API 1 TTPs

    The Task Scheduler COM API can be used to schedule applications to run on boot or at set times.

Processes

  • C:\Users\Admin\AppData\Local\Temp\Client-built.exe
    "C:\Users\Admin\AppData\Local\Temp\Client-built.exe"
    1⤵
    • Suspicious use of AdjustPrivilegeToken
    • Suspicious use of WriteProcessMemory
    PID:4564
    • C:\Windows\SYSTEM32\schtasks.exe
      "schtasks" /create /tn "Windows Updater" /sc ONLOGON /tr "C:\Users\Admin\AppData\Roaming\Windows\WOS64UPD.exe" /rl HIGHEST /f
      2⤵
      • Creates scheduled task(s)
      PID:3876
    • C:\Users\Admin\AppData\Roaming\Windows\WOS64UPD.exe
      "C:\Users\Admin\AppData\Roaming\Windows\WOS64UPD.exe"
      2⤵
      • Executes dropped EXE
      • Suspicious use of AdjustPrivilegeToken
      • Suspicious use of SetWindowsHookEx
      • Suspicious use of WriteProcessMemory
      PID:4932
      • C:\Windows\SYSTEM32\schtasks.exe
        "schtasks" /create /tn "Windows Updater" /sc ONLOGON /tr "C:\Users\Admin\AppData\Roaming\Windows\WOS64UPD.exe" /rl HIGHEST /f
        3⤵
        • Creates scheduled task(s)
        PID:824

Network

        MITRE ATT&CK Enterprise v15

        Replay Monitor

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        Downloads

        WOS64UPD.exe

        • Path C:\Users\Admin\AppData\Roaming\Windows\WOS64UPD.exe
        • Size 3.1MB
        • SHA256 f2e04196e1353ad216e077e0aeb2e1ab8ee93b8b16b205422b4cc6d8adc50cc2
        • MD5 SHA1 SHA512 SSDEEP

        memory/4564-0-0x0000000000FA0000-0x00000000012C4000-memory.dmp

        memory/4564-1-0x00007FFF710E0000-0x00007FFF71ACC000-memory.dmp

        memory/4564-2-0x000000001C0A0000-0x000000001C0B0000-memory.dmp

        memory/4564-8-0x00007FFF710E0000-0x00007FFF71ACC000-memory.dmp

        memory/4932-10-0x0000000003040000-0x0000000003050000-memory.dmp

        memory/4932-9-0x00007FFF710E0000-0x00007FFF71ACC000-memory.dmp

        memory/4932-11-0x000000001C2D0000-0x000000001C320000-memory.dmp

        memory/4932-12-0x000000001C3E0000-0x000000001C492000-memory.dmp

        memory/4932-15-0x000000001C380000-0x000000001C392000-memory.dmp

        memory/4932-16-0x000000001CED0000-0x000000001CF0E000-memory.dmp

        memory/4932-17-0x00007FFF710E0000-0x00007FFF71ACC000-memory.dmp

        memory/4932-18-0x0000000003040000-0x0000000003050000-memory.dmp