Analysis

  • max time kernel
    62s
  • max time network
    125s
  • platform
    windows10-2004_x64
  • resource
    win10v2004-20220721-en
  • resource tags

    arch:x64arch:x86image:win10v2004-20220721-enlocale:en-usos:windows10-2004-x64system
  • submitted
    27-07-2022 15:07

General

  • Target

    gunzipped.exe

  • Size

    730KB

  • MD5

    02c69e67c2f23c547d0022147da9fbe9

  • SHA1

    6686b9d64df9a2c31f61c5a6682b2d899ab1a599

  • SHA256

    c87ec3f9dfb87a10f1c38102a3c58bc2cbb252891b5c882f3c4f3f0a9058b170

  • SHA512

    7fcd69e6b1eb521200d7111ff120f9fb2b67ff76f3bb49372781a9469224831ca21aad0955e1b72bd98d677450c8726053601b703818a8573e4cded9b3950c73

Malware Config

Extracted

Family

oski

C2

master101work.co

Signatures

  • Oski

    Oski is an infostealer targeting browser data, crypto wallets.

  • Downloads MZ/PE file
  • Checks computer location settings 2 TTPs 2 IoCs

    Looks up country code configured in the registry, likely geofence.

  • 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.

  • Creates scheduled task(s) 1 TTPs 1 IoCs

    Schtasks is often used by malware for persistence or to perform post-infection execution.

  • Kills process with taskkill 1 IoCs
  • Suspicious behavior: EnumeratesProcesses 2 IoCs
  • Suspicious use of AdjustPrivilegeToken 2 IoCs
  • Suspicious use of WriteProcessMemory 21 IoCs

Processes

  • C:\Users\Admin\AppData\Local\Temp\gunzipped.exe
    "C:\Users\Admin\AppData\Local\Temp\gunzipped.exe"
    1⤵
    • Checks computer location settings
    • Suspicious use of SetThreadContext
    • Suspicious use of WriteProcessMemory
    PID:4492
    • C:\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell.exe
      "C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe" Add-MpPreference -ExclusionPath "C:\Users\Admin\AppData\Roaming\yGkHpD.exe"
      2⤵
      • Suspicious behavior: EnumeratesProcesses
      • Suspicious use of AdjustPrivilegeToken
      PID:60
    • C:\Windows\SysWOW64\schtasks.exe
      "C:\Windows\System32\schtasks.exe" /Create /TN "Updates\yGkHpD" /XML "C:\Users\Admin\AppData\Local\Temp\tmp4249.tmp"
      2⤵
      • Creates scheduled task(s)
      PID:1020
    • C:\Users\Admin\AppData\Local\Temp\gunzipped.exe
      "C:\Users\Admin\AppData\Local\Temp\gunzipped.exe"
      2⤵
      • Checks computer location settings
      • Loads dropped DLL
      • Checks processor information in registry
      • Suspicious use of WriteProcessMemory
      PID:2060
      • C:\Windows\SysWOW64\cmd.exe
        "C:\Windows\System32\cmd.exe" /c taskkill /pid 2060 & erase C:\Users\Admin\AppData\Local\Temp\gunzipped.exe & RD /S /Q C:\\ProgramData\\703565485021732\\* & exit
        3⤵
        • Suspicious use of WriteProcessMemory
        PID:4264
        • C:\Windows\SysWOW64\taskkill.exe
          taskkill /pid 2060
          4⤵
          • Kills process with taskkill
          • Suspicious use of AdjustPrivilegeToken
          PID:4516

Network

MITRE ATT&CK Matrix ATT&CK v6

Execution

Scheduled Task

1
T1053

Persistence

Scheduled Task

1
T1053

Privilege Escalation

Scheduled Task

1
T1053

Credential Access

Credentials in Files

2
T1081

Discovery

Query Registry

3
T1012

System Information Discovery

3
T1082

Collection

Data from Local System

2
T1005

Replay Monitor

Loading Replay Monitor...

Downloads

  • C:\ProgramData\mozglue.dll
    Filesize

    133KB

    MD5

    8f73c08a9660691143661bf7332c3c27

    SHA1

    37fa65dd737c50fda710fdbde89e51374d0c204a

    SHA256

    3fe6b1c54b8cf28f571e0c5d6636b4069a8ab00b4f11dd842cfec00691d0c9cd

    SHA512

    0042ecf9b3571bb5eba2de893e8b2371df18f7c5a589f52ee66e4bfbaa15a5b8b7cc6a155792aaa8988528c27196896d5e82e1751c998bacea0d92395f66ad89

  • C:\ProgramData\nss3.dll
    Filesize

    1.2MB

    MD5

    bfac4e3c5908856ba17d41edcd455a51

    SHA1

    8eec7e888767aa9e4cca8ff246eb2aacb9170428

    SHA256

    e2935b5b28550d47dc971f456d6961f20d1633b4892998750140e0eaa9ae9d78

    SHA512

    2565bab776c4d732ffb1f9b415992a4c65b81bcd644a9a1df1333a269e322925fc1df4f76913463296efd7c88ef194c3056de2f1ca1357d7b5fe5ff0da877a66

  • C:\ProgramData\sqlite3.dll
    Filesize

    630KB

    MD5

    e477a96c8f2b18d6b5c27bde49c990bf

    SHA1

    e980c9bf41330d1e5bd04556db4646a0210f7409

    SHA256

    16574f51785b0e2fc29c2c61477eb47bb39f714829999511dc8952b43ab17660

    SHA512

    335a86268e7c0e568b1c30981ec644e6cd332e66f96d2551b58a82515316693c1859d87b4f4b7310cf1ac386cee671580fdd999c3bcb23acf2c2282c01c8798c

  • C:\Users\Admin\AppData\Local\Temp\tmp4249.tmp
    Filesize

    1KB

    MD5

    93c12798bd0589dc3f8599de8ca4b033

    SHA1

    6a53d062e48d28a7068b0eac3fbf1ac1599eccc5

    SHA256

    ad90c85b673456e14ab90cbc2df71e6ae54242db942d3d9d7c0a1d0316d4b744

    SHA512

    02653a406e6de4719cb821f54c530b31f117371b5c3688bbc3e766be6e434a819cc5c7d9cfdf5422766aee8928bc2db1e84b27be9aa653aac31028c490c81735

  • memory/60-146-0x0000000005240000-0x0000000005262000-memory.dmp
    Filesize

    136KB

  • memory/60-161-0x0000000007660000-0x00000000076F6000-memory.dmp
    Filesize

    600KB

  • memory/60-136-0x0000000000000000-mapping.dmp
  • memory/60-153-0x00000000706E0000-0x000000007072C000-memory.dmp
    Filesize

    304KB

  • memory/60-138-0x00000000027E0000-0x0000000002816000-memory.dmp
    Filesize

    216KB

  • memory/60-164-0x0000000007700000-0x0000000007708000-memory.dmp
    Filesize

    32KB

  • memory/60-163-0x0000000007720000-0x000000000773A000-memory.dmp
    Filesize

    104KB

  • memory/60-162-0x0000000007610000-0x000000000761E000-memory.dmp
    Filesize

    56KB

  • memory/60-142-0x0000000005350000-0x0000000005978000-memory.dmp
    Filesize

    6.2MB

  • memory/60-152-0x0000000007090000-0x00000000070C2000-memory.dmp
    Filesize

    200KB

  • memory/60-160-0x0000000007450000-0x000000000745A000-memory.dmp
    Filesize

    40KB

  • memory/60-159-0x00000000073E0000-0x00000000073FA000-memory.dmp
    Filesize

    104KB

  • memory/60-158-0x0000000007A30000-0x00000000080AA000-memory.dmp
    Filesize

    6.5MB

  • memory/60-147-0x0000000005A20000-0x0000000005A86000-memory.dmp
    Filesize

    408KB

  • memory/60-148-0x00000000060E0000-0x00000000060FE000-memory.dmp
    Filesize

    120KB

  • memory/60-154-0x0000000006690000-0x00000000066AE000-memory.dmp
    Filesize

    120KB

  • memory/1020-137-0x0000000000000000-mapping.dmp
  • memory/2060-156-0x0000000000400000-0x0000000000438000-memory.dmp
    Filesize

    224KB

  • memory/2060-145-0x0000000000400000-0x0000000000438000-memory.dmp
    Filesize

    224KB

  • memory/2060-140-0x0000000000000000-mapping.dmp
  • memory/2060-141-0x0000000000400000-0x0000000000438000-memory.dmp
    Filesize

    224KB

  • memory/2060-143-0x0000000000400000-0x0000000000438000-memory.dmp
    Filesize

    224KB

  • memory/2060-144-0x0000000000400000-0x0000000000438000-memory.dmp
    Filesize

    224KB

  • memory/4264-155-0x0000000000000000-mapping.dmp
  • memory/4492-130-0x00000000005E0000-0x000000000069C000-memory.dmp
    Filesize

    752KB

  • memory/4492-135-0x000000000B0E0000-0x000000000B146000-memory.dmp
    Filesize

    408KB

  • memory/4492-131-0x0000000005700000-0x0000000005CA4000-memory.dmp
    Filesize

    5.6MB

  • memory/4492-133-0x00000000050D0000-0x00000000050DA000-memory.dmp
    Filesize

    40KB

  • memory/4492-132-0x0000000005030000-0x00000000050C2000-memory.dmp
    Filesize

    584KB

  • memory/4492-134-0x00000000072C0000-0x000000000735C000-memory.dmp
    Filesize

    624KB

  • memory/4516-157-0x0000000000000000-mapping.dmp