Analysis

  • max time kernel
    118s
  • max time network
    120s
  • platform
    windows7_x64
  • resource
    win7v20210410
  • 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
  • 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
  • Suspicious behavior: EnumeratesProcesses 2 IoCs
  • Suspicious use of AdjustPrivilegeToken 2 IoCs
  • Suspicious use of WriteProcessMemory 22 IoCs

Processes

  • C:\Users\Admin\AppData\Local\Temp\7536b74c17754363799df14fe70d3a92.exe
    "C:\Users\Admin\AppData\Local\Temp\7536b74c17754363799df14fe70d3a92.exe"
    1⤵
    • Suspicious use of SetThreadContext
    • Suspicious behavior: EnumeratesProcesses
    • Suspicious use of AdjustPrivilegeToken
    • Suspicious use of WriteProcessMemory
    PID:1048
    • C:\Users\Admin\AppData\Local\Temp\7536b74c17754363799df14fe70d3a92.exe
      "C:\Users\Admin\AppData\Local\Temp\7536b74c17754363799df14fe70d3a92.exe"
      2⤵
        PID:892
      • 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:240
        • C:\Windows\SysWOW64\cmd.exe
          "C:\Windows\System32\cmd.exe" /c taskkill /pid 240 & erase C:\Users\Admin\AppData\Local\Temp\7536b74c17754363799df14fe70d3a92.exe & RD /S /Q C:\\ProgramData\\589255945486881\\* & exit
          3⤵
          • Deletes itself
          • Suspicious use of WriteProcessMemory
          PID:340
          • C:\Windows\SysWOW64\taskkill.exe
            taskkill /pid 240
            4⤵
            • Kills process with taskkill
            • Suspicious use of AdjustPrivilegeToken
            PID:1556

    Network

          MITRE ATT&CK Enterprise v6

          Replay Monitor

          Loading Replay Monitor...

          Downloads

          • memory/240-69-0x0000000000400000-0x0000000000438000-memory.dmp

            Filesize

            224KB

          • memory/240-66-0x0000000000400000-0x0000000000438000-memory.dmp

            Filesize

            224KB

          • memory/240-68-0x0000000075721000-0x0000000075723000-memory.dmp

            Filesize

            8KB

          • memory/1048-60-0x0000000001240000-0x0000000001241000-memory.dmp

            Filesize

            4KB

          • memory/1048-65-0x0000000000670000-0x00000000006A6000-memory.dmp

            Filesize

            216KB

          • memory/1048-64-0x0000000005760000-0x00000000057FD000-memory.dmp

            Filesize

            628KB

          • memory/1048-63-0x00000000003E0000-0x00000000003ED000-memory.dmp

            Filesize

            52KB

          • memory/1048-62-0x00000000011E0000-0x00000000011E1000-memory.dmp

            Filesize

            4KB