Analysis

  • max time kernel
    59s
  • max time network
    148s
  • platform
    windows10_x64
  • resource
    win10v20210410
  • submitted
    28/04/2021, 03:41

General

  • Target
    IMG0537521501.exe
  • Size 218KB
  • Sample210428-ncb2swdxbx
  • SHA256 a5c9be9bcb214e69a39285a634f95e43fdf1ad10536bcc9bce84be7edb48cb31
  • MD5 SHA1 SHA512

Malware Config

Extracted

Family
  • oski

C2
  • 31.210.20.238

Signatures

  • Oski

    Oski is an infostealer targeting browser data, crypto wallets.

  • Downloads MZ/PE file
  • Loads dropped DLL 3 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
  • Suspicious behavior: EnumeratesProcesses 6 IoCs
  • Suspicious use of AdjustPrivilegeToken 2 IoCs
  • Suspicious use of WriteProcessMemory 18 IoCs

Processes

  • C:\Users\Admin\AppData\Local\Temp\IMG0537521501.exe
    "C:\Users\Admin\AppData\Local\Temp\IMG0537521501.exe"
    1⤵
    • Suspicious use of SetThreadContext
    • Suspicious behavior: EnumeratesProcesses
    • Suspicious use of AdjustPrivilegeToken
    • Suspicious use of WriteProcessMemory
    PID:4440
    • C:\Users\Admin\AppData\Local\Temp\IMG0537521501.exe
      C:\Users\Admin\AppData\Local\Temp\IMG0537521501.exe
      2⤵
        PID:1832
      • C:\Users\Admin\AppData\Local\Temp\IMG0537521501.exe
        C:\Users\Admin\AppData\Local\Temp\IMG0537521501.exe
        2⤵
        • Loads dropped DLL
        • Checks processor information in registry
        • Suspicious use of WriteProcessMemory
        PID:1936
        • C:\Windows\SysWOW64\cmd.exe
          "C:\Windows\System32\cmd.exe" /c taskkill /pid 1936 & erase C:\Users\Admin\AppData\Local\Temp\IMG0537521501.exe & RD /S /Q C:\\ProgramData\\026095113336674\\* & exit
          3⤵
          • Suspicious use of WriteProcessMemory
          PID:4004
          • C:\Windows\SysWOW64\taskkill.exe
            taskkill /pid 1936
            4⤵
            • Kills process with taskkill
            • Suspicious use of AdjustPrivilegeToken
            PID:3196

    Network

          MITRE ATT&CK Enterprise v6

          Replay Monitor

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          Downloads

          memory/1936-122-0x0000000000400000-0x0000000000438000-memory.dmp

          memory/1936-124-0x0000000000400000-0x0000000000438000-memory.dmp

          memory/4440-118-0x0000000004CB0000-0x0000000004CB1000-memory.dmp

          memory/4440-121-0x0000000004C30000-0x0000000004C4C000-memory.dmp

          memory/4440-120-0x0000000004BE0000-0x0000000004BE1000-memory.dmp

          memory/4440-119-0x0000000004DC0000-0x0000000004DC1000-memory.dmp

          memory/4440-114-0x0000000000350000-0x0000000000351000-memory.dmp

          memory/4440-117-0x0000000002730000-0x0000000002732000-memory.dmp

          memory/4440-116-0x00000000052D0000-0x00000000052D1000-memory.dmp