Analysis

  • max time kernel
    151s
  • max time network
    159s
  • platform
    windows11-21h2_x64
  • resource
    win11-20240221-en
  • resource tags

    arch:x64arch:x86image:win11-20240221-enlocale:en-usos:windows11-21h2-x64system
  • submitted
    23/03/2024, 19:56

General

  • Target
    Client-built.exe
  • Size 348KB
  • Sample240323-yn5kcaeb6s
  • SHA256 169c150e8f08da5a4ab2b46bc67cdd1d2d006a060b39d66e559dbfdc53017414
  • MD5 SHA1 SHA512 SSDEEP

Malware Config

Extracted

Family
  • quasar

Version
  • 1.3.0.0

Botnet
  • Office04

C2
  • Vallithebest-32755.portmap.host:32755

Mutex
  • QSR_MUTEX_3gXoc7Rbb6gDK9k7Ha

Attributes
  • encryption_key

    MgIQlrEArYoUL3gDO4iZ

  • install_name

    WindowsSound.exe

  • log_directory

    Logs

  • reconnect_delay

    3000

  • startup_key

    WindowsSound.exe

  • subdirectory

    SubDir

Signatures

  • Quasar RAT

    Quasar is an open source Remote Access Tool.

  • Quasar payload 2 IoCs
  • Executes dropped EXE 1 IoCs
  • Adds Run key to start application 2 TTPs 1 IoCs
  • Looks up external IP address via web service 1 IoCs

    Uses a legitimate IP lookup service to find the infected system's external IP.

  • 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 9 IoCs

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:3140
    • C:\Windows\SysWOW64\schtasks.exe
      "schtasks" /create /tn "WindowsSound.exe" /sc ONLOGON /tr "C:\Users\Admin\AppData\Local\Temp\Client-built.exe" /rl HIGHEST /f
      2⤵
      • Creates scheduled task(s)
      PID:2000
    • C:\Users\Admin\AppData\Roaming\SubDir\WindowsSound.exe
      "C:\Users\Admin\AppData\Roaming\SubDir\WindowsSound.exe"
      2⤵
      • Executes dropped EXE
      • Adds Run key to start application
      • Suspicious use of AdjustPrivilegeToken
      • Suspicious use of SetWindowsHookEx
      • Suspicious use of WriteProcessMemory
      PID:1108
      • C:\Windows\SysWOW64\schtasks.exe
        "schtasks" /create /tn "WindowsSound.exe" /sc ONLOGON /tr "C:\Users\Admin\AppData\Roaming\SubDir\WindowsSound.exe" /rl HIGHEST /f
        3⤵
        • Creates scheduled task(s)
        PID:500

Network

        MITRE ATT&CK Enterprise v15

        Replay Monitor

        Loading Replay Monitor...

        Downloads

        WindowsSound.exe

        • Path C:\Users\Admin\AppData\Roaming\SubDir\WindowsSound.exe
        • Size 348KB
        • SHA256 169c150e8f08da5a4ab2b46bc67cdd1d2d006a060b39d66e559dbfdc53017414
        • MD5 SHA1 SHA512 SSDEEP

        memory/1108-20-0x0000000005800000-0x0000000005810000-memory.dmp

        memory/1108-19-0x0000000074B20000-0x00000000752D1000-memory.dmp

        memory/1108-18-0x0000000006E80000-0x0000000006E8A000-memory.dmp

        memory/1108-16-0x0000000005800000-0x0000000005810000-memory.dmp

        memory/1108-14-0x0000000074B20000-0x00000000752D1000-memory.dmp

        memory/3140-6-0x0000000006740000-0x0000000006752000-memory.dmp

        memory/3140-7-0x0000000006B90000-0x0000000006BCC000-memory.dmp

        memory/3140-0-0x0000000000D10000-0x0000000000D6E000-memory.dmp

        memory/3140-15-0x0000000074B20000-0x00000000752D1000-memory.dmp

        memory/3140-5-0x00000000059A0000-0x0000000005A06000-memory.dmp

        memory/3140-4-0x00000000057A0000-0x00000000057B0000-memory.dmp

        memory/3140-3-0x00000000057B0000-0x0000000005842000-memory.dmp

        memory/3140-2-0x0000000005E50000-0x00000000063F6000-memory.dmp

        memory/3140-1-0x0000000074B20000-0x00000000752D1000-memory.dmp