Analysis

  • max time kernel
    55s
  • max time network
    136s
  • platform
    windows10_x64
  • resource
    win10v20210408
  • submitted
    03/08/2021, 11:03

General

  • Target

    7536b74c17754363799df14fe70d3a92.exe

  • Size

    995KB

  • MD5

    7536b74c17754363799df14fe70d3a92

  • SHA1

    790969675e8cec28cf19c18625dd764884459b01

  • SHA256

    60d1297adb502d942493a794945336aea891d2c321476ef3349ac07726fca7c3

  • SHA512

    8f706b646a4a9c3549ffda3e14bfe5724c3287e0f4dfbe853888c7e529dedaccd00af2ed933fe1e7d21de26b88b96f2ffe08319570751215975f0a3524a4e8fd

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
  • 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 use of AdjustPrivilegeToken 1 IoCs
  • Suspicious use of WriteProcessMemory 15 IoCs

Processes

  • C:\Users\Admin\AppData\Local\Temp\7536b74c17754363799df14fe70d3a92.exe
    "C:\Users\Admin\AppData\Local\Temp\7536b74c17754363799df14fe70d3a92.exe"
    1⤵
    • Suspicious use of SetThreadContext
    • Suspicious use of WriteProcessMemory
    PID:3128
    • C:\Users\Admin\AppData\Local\Temp\7536b74c17754363799df14fe70d3a92.exe
      "C:\Users\Admin\AppData\Local\Temp\7536b74c17754363799df14fe70d3a92.exe"
      2⤵
      • Loads dropped DLL
      • Checks processor information in registry
      • Suspicious use of WriteProcessMemory
      PID:3476
      • C:\Windows\SysWOW64\cmd.exe
        "C:\Windows\System32\cmd.exe" /c taskkill /pid 3476 & erase C:\Users\Admin\AppData\Local\Temp\7536b74c17754363799df14fe70d3a92.exe & RD /S /Q C:\\ProgramData\\988647133445575\\* & exit
        3⤵
        • Suspicious use of WriteProcessMemory
        PID:2696
        • C:\Windows\SysWOW64\taskkill.exe
          taskkill /pid 3476
          4⤵
          • Kills process with taskkill
          • Suspicious use of AdjustPrivilegeToken
          PID:3472

Network

        MITRE ATT&CK Enterprise v6

        Replay Monitor

        Loading Replay Monitor...

        Downloads

        • memory/3128-123-0x00000000072D0000-0x000000000736D000-memory.dmp

          Filesize

          628KB

        • memory/3128-118-0x0000000004BD0000-0x0000000004BD1000-memory.dmp

          Filesize

          4KB

        • memory/3128-121-0x0000000004D70000-0x0000000004D71000-memory.dmp

          Filesize

          4KB

        • memory/3128-122-0x0000000004BC0000-0x0000000004BCD000-memory.dmp

          Filesize

          52KB

        • memory/3128-114-0x0000000000120000-0x0000000000121000-memory.dmp

          Filesize

          4KB

        • memory/3128-124-0x0000000004500000-0x0000000004536000-memory.dmp

          Filesize

          216KB

        • memory/3128-116-0x0000000004A40000-0x0000000004A41000-memory.dmp

          Filesize

          4KB

        • memory/3128-117-0x0000000005030000-0x0000000005031000-memory.dmp

          Filesize

          4KB

        • memory/3128-120-0x0000000004A20000-0x0000000004A21000-memory.dmp

          Filesize

          4KB

        • memory/3128-119-0x0000000004B30000-0x000000000502E000-memory.dmp

          Filesize

          5.0MB

        • memory/3476-127-0x0000000000400000-0x0000000000438000-memory.dmp

          Filesize

          224KB

        • memory/3476-125-0x0000000000400000-0x0000000000438000-memory.dmp

          Filesize

          224KB