Analysis

  • max time kernel
    15s
  • max time network
    39s
  • platform
    windows7_x64
  • resource
    win7v20210410
  • submitted
    03/08/2021, 11:17

General

  • Target

    da484abefb23789c13add9ecd7ea7eeb.exe

  • Size

    693KB

  • MD5

    da484abefb23789c13add9ecd7ea7eeb

  • SHA1

    cf0098c51761c3c9b860cdfd290734f0d1657bba

  • SHA256

    223dfd54929007ac23d6a20dbcf81a519a14f1c4061d23afcb761b75796042d2

  • SHA512

    380d3227555739a95ae2514fbe1f24882cbf91db508339837aee2fc6d1ac1c5a7feabcef9bf87ebc8b4efe6fa1f142f2ad9efd595899875fd1e416aa1965d368

Malware Config

Extracted

Family

oski

C2

http://2.56.59.226/www/

Signatures

  • Oski

    Oski is an infostealer targeting browser data, crypto wallets.

  • suricata: ET MALWARE Suspicious Zipped Filename in Outbound POST Request (Passwords.txt)
  • suricata: ET MALWARE Vidar/Arkei/Megumin/Oski Stealer Data Exfil
  • Downloads MZ/PE file
  • Deletes itself 1 IoCs
  • Loads dropped DLL 5 IoCs
  • Reads user/profile data of web browsers 2 TTPs

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

  • Accesses cryptocurrency files/wallets, possible credential harvesting 2 TTPs
  • Checks installed software on the system 1 TTPs

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

  • Suspicious use of SetThreadContext 1 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 1 IoCs

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

  • Kills process with taskkill 1 IoCs
  • Modifies Internet Explorer settings 1 TTPs 1 IoCs
  • Suspicious use of AdjustPrivilegeToken 2 IoCs
  • Suspicious use of SetWindowsHookEx 2 IoCs
  • Suspicious use of WriteProcessMemory 19 IoCs

Processes

  • C:\Users\Admin\AppData\Local\Temp\da484abefb23789c13add9ecd7ea7eeb.exe
    "C:\Users\Admin\AppData\Local\Temp\da484abefb23789c13add9ecd7ea7eeb.exe"
    1⤵
    • Suspicious use of SetThreadContext
    • Modifies Internet Explorer settings
    • Suspicious use of AdjustPrivilegeToken
    • Suspicious use of SetWindowsHookEx
    • Suspicious use of WriteProcessMemory
    PID:916
    • C:\Users\Admin\AppData\Local\Temp\da484abefb23789c13add9ecd7ea7eeb.exe
      "C:\Users\Admin\AppData\Local\Temp\da484abefb23789c13add9ecd7ea7eeb.exe"
      2⤵
      • Loads dropped DLL
      • Checks processor information in registry
      • Suspicious use of WriteProcessMemory
      PID:756
      • C:\Windows\SysWOW64\cmd.exe
        "C:\Windows\System32\cmd.exe" /c taskkill /pid 756 & erase C:\Users\Admin\AppData\Local\Temp\da484abefb23789c13add9ecd7ea7eeb.exe & RD /S /Q C:\\ProgramData\\420531560174735\\* & exit
        3⤵
        • Deletes itself
        • Suspicious use of WriteProcessMemory
        PID:1144
        • C:\Windows\SysWOW64\taskkill.exe
          taskkill /pid 756
          4⤵
          • Kills process with taskkill
          • Suspicious use of AdjustPrivilegeToken
          PID:920

Network

        MITRE ATT&CK Enterprise v6

        Replay Monitor

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        Downloads

        • memory/756-69-0x0000000075011000-0x0000000075013000-memory.dmp

          Filesize

          8KB

        • memory/756-67-0x0000000000400000-0x000000000047F000-memory.dmp

          Filesize

          508KB

        • memory/756-70-0x0000000000400000-0x000000000047F000-memory.dmp

          Filesize

          508KB

        • memory/916-60-0x0000000000970000-0x0000000000971000-memory.dmp

          Filesize

          4KB

        • memory/916-66-0x0000000008910000-0x000000000898E000-memory.dmp

          Filesize

          504KB

        • memory/916-63-0x00000000043D1000-0x00000000043D2000-memory.dmp

          Filesize

          4KB

        • memory/916-65-0x00000000043D7000-0x00000000043E8000-memory.dmp

          Filesize

          68KB

        • memory/916-64-0x00000000043D2000-0x00000000043D3000-memory.dmp

          Filesize

          4KB

        • memory/916-62-0x00000000043D0000-0x00000000043D1000-memory.dmp

          Filesize

          4KB