Analysis

  • max time kernel
    155s
  • max time network
    159s
  • platform
    windows7_x64
  • resource
    win7-en
  • submitted
    03/09/2021, 09:06

General

  • Target
    3a3c73c139d12addf585756334a51fb8ca6381a27531c67ba306923a08fbb05e.exe
  • Size 794KB
  • Sample210903-k2rnragack
  • SHA256 3a3c73c139d12addf585756334a51fb8ca6381a27531c67ba306923a08fbb05e
  • MD5 SHA1 SHA512

Malware Config

Extracted

Family
  • vidar

Version
  • 40.4

Botnet
  • 517

C2
  • https://romkaxarit.tumblr.com/

Attributes
  • profile_id

    517

Signatures

  • Detected Djvu ransomeware 6 IoCs
  • Djvu Ransomware

    Ransomware which is a variant of the STOP family.

  • Vidar

    Vidar is an infostealer based on Arkei stealer.

  • suricata: ET MALWARE Potential Dridex.Maldoc Minimal Executable Request

    suricata: ET MALWARE Potential Dridex.Maldoc Minimal Executable Request

  • suricata: ET MALWARE Suspicious Zipped Filename in Outbound POST Request (Passwords.txt)

    suricata: ET MALWARE Suspicious Zipped Filename in Outbound POST Request (Passwords.txt)

  • suricata: ET MALWARE Vidar/Arkei Stealer Client Data Upload

    suricata: ET MALWARE Vidar/Arkei Stealer Client Data Upload

  • suricata: ET MALWARE Vidar/Arkei/Megumin/Oski Stealer Data Exfil

    suricata: ET MALWARE Vidar/Arkei/Megumin/Oski Stealer Data Exfil

  • Vidar Stealer 4 IoCs
  • Downloads MZ/PE file
  • Executes dropped EXE 2 IoCs
  • Loads dropped DLL 6 IoCs
  • Modifies file permissions 1 TTPs 1 IoCs
  • Reads user/profile data of web browsers 2 TTPs

    Infostealers often target stored browser data, which can include saved credentials etc.

  • Accesses 2FA software files, possible credential harvesting 2 TTPs
  • Accesses cryptocurrency files/wallets, possible credential harvesting 2 TTPs
  • Adds Run key to start application 2 TTPs 1 IoCs
  • Checks installed software on the system 1 TTPs

    Looks up Uninstall key entries in the registry to enumerate software on the system.

  • Looks up external IP address via web service 2 IoCs

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

  • Suspicious use of SetThreadContext 3 IoCs
  • Enumerates physical storage devices 1 TTPs

    Attempts to interact with connected storage/optical drive(s). Likely ransomware behaviour.

  • Checks processor information in registry 2 TTPs 2 IoCs

    Processor information is often read in order to detect sandboxing environments.

  • Delays execution with timeout.exe 1 IoCs
  • Kills process with taskkill 1 IoCs
  • Modifies system certificate store 2 TTPs 5 IoCs
  • Suspicious behavior: EnumeratesProcesses 8 IoCs
  • Suspicious use of AdjustPrivilegeToken 1 IoCs
  • Suspicious use of WriteProcessMemory 55 IoCs

Processes

  • C:\Users\Admin\AppData\Local\Temp\3a3c73c139d12addf585756334a51fb8ca6381a27531c67ba306923a08fbb05e.exe
    "C:\Users\Admin\AppData\Local\Temp\3a3c73c139d12addf585756334a51fb8ca6381a27531c67ba306923a08fbb05e.exe"
    1⤵
    • Suspicious use of SetThreadContext
    • Suspicious use of WriteProcessMemory
    PID:1836
    • C:\Users\Admin\AppData\Local\Temp\3a3c73c139d12addf585756334a51fb8ca6381a27531c67ba306923a08fbb05e.exe
      "C:\Users\Admin\AppData\Local\Temp\3a3c73c139d12addf585756334a51fb8ca6381a27531c67ba306923a08fbb05e.exe"
      2⤵
      • Adds Run key to start application
      • Modifies system certificate store
      • Suspicious behavior: EnumeratesProcesses
      • Suspicious use of WriteProcessMemory
      PID:1752
      • C:\Windows\SysWOW64\icacls.exe
        icacls "C:\Users\Admin\AppData\Local\e95b9bb4-adca-479b-a789-85d3f53fb3a5" /deny *S-1-1-0:(OI)(CI)(DE,DC)
        3⤵
        • Modifies file permissions
        PID:1284
      • C:\Users\Admin\AppData\Local\Temp\3a3c73c139d12addf585756334a51fb8ca6381a27531c67ba306923a08fbb05e.exe
        "C:\Users\Admin\AppData\Local\Temp\3a3c73c139d12addf585756334a51fb8ca6381a27531c67ba306923a08fbb05e.exe" --Admin IsNotAutoStart IsNotTask
        3⤵
        • Suspicious use of SetThreadContext
        • Suspicious use of WriteProcessMemory
        PID:1268
        • C:\Users\Admin\AppData\Local\Temp\3a3c73c139d12addf585756334a51fb8ca6381a27531c67ba306923a08fbb05e.exe
          "C:\Users\Admin\AppData\Local\Temp\3a3c73c139d12addf585756334a51fb8ca6381a27531c67ba306923a08fbb05e.exe" --Admin IsNotAutoStart IsNotTask
          4⤵
          • Loads dropped DLL
          • Suspicious behavior: EnumeratesProcesses
          • Suspicious use of WriteProcessMemory
          PID:824
          • C:\Users\Admin\AppData\Local\eaddc13f-1ec6-42de-b431-921acc10e7b6\build2.exe
            "C:\Users\Admin\AppData\Local\eaddc13f-1ec6-42de-b431-921acc10e7b6\build2.exe"
            5⤵
            • Executes dropped EXE
            • Suspicious use of SetThreadContext
            • Suspicious use of WriteProcessMemory
            PID:1836
            • C:\Users\Admin\AppData\Local\eaddc13f-1ec6-42de-b431-921acc10e7b6\build2.exe
              "C:\Users\Admin\AppData\Local\eaddc13f-1ec6-42de-b431-921acc10e7b6\build2.exe"
              6⤵
              • Executes dropped EXE
              • Loads dropped DLL
              • Checks processor information in registry
              • Modifies system certificate store
              • Suspicious behavior: EnumeratesProcesses
              • Suspicious use of WriteProcessMemory
              PID:1020
              • C:\Windows\SysWOW64\cmd.exe
                "C:\Windows\System32\cmd.exe" /c taskkill /im build2.exe /f & timeout /t 6 & del /f /q "C:\Users\Admin\AppData\Local\eaddc13f-1ec6-42de-b431-921acc10e7b6\build2.exe" & del C:\ProgramData\*.dll & exit
                7⤵
                • Suspicious use of WriteProcessMemory
                PID:1420
                • C:\Windows\SysWOW64\taskkill.exe
                  taskkill /im build2.exe /f
                  8⤵
                  • Kills process with taskkill
                  • Suspicious use of AdjustPrivilegeToken
                  PID:1040
                • C:\Windows\SysWOW64\timeout.exe
                  timeout /t 6
                  8⤵
                  • Delays execution with timeout.exe
                  PID:1736

Network

        MITRE ATT&CK Enterprise v6

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        Downloads

        memory/824-64-0x0000000000400000-0x0000000000537000-memory.dmp

        memory/1020-75-0x0000000000400000-0x00000000004D7000-memory.dmp

        memory/1020-70-0x0000000000400000-0x00000000004D7000-memory.dmp

        memory/1752-57-0x0000000000400000-0x0000000000537000-memory.dmp

        memory/1752-53-0x0000000000400000-0x0000000000537000-memory.dmp

        memory/1752-56-0x00000000758D1000-0x00000000758D3000-memory.dmp

        memory/1836-73-0x0000000004510000-0x00000000045E3000-memory.dmp

        memory/1836-55-0x0000000002440000-0x000000000255B000-memory.dmp