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  њ      њ    -  -- A C i D B U R N - P R O D U C T i O N S --  -    њ     њ
                                SRT - CRO



        JAVA REVERSE ENGINEERING: How to defeat java !
								 
		Tutorial by ACiD BuRN [Immortal Descendants]			 
                             (October 23th, 1999) 			





Intro:

ok , it is really easy to reverse java apps , when u got a decompiler !!
i will show u how easy can be java reversing , but there is harder things , like
name / serial apps.I never seen anyone yet , but there is somes already done !

Tools needed:
		- JAD (java decompiler)
		- nothing more :)	


URLS:           http://www.lawrencegoetz.com/   (the java target app)
                http://acidburn2000.cjb.net/    (the java decompiler soon on my site)


In this tutor we will crack 3 Things : Goetz's Banner V 2.0 , Goetz's Marquee 1.1,
and ManKind java crackme !


ok , lets start

unzip the Goetz's Banner V 2.0 archive in one directory.You must see some files , and if 
you run the sample file , (exemple.html) you see the banner effect due of this nice
java thingy , but A BIG UNREGISTERED SHIT is shown !! hehe Doh :p
so, Java files are '.class' , so just click on the gbanner.class file , and move it on
Jad.exe to decompile it!!
But it is better to make a Bat file becoz , the decompiled file might be in the Windows
directory!
anyway , if you can find it , just do a search on your hard disk on gbanner.jad
Ok, now you have this file , open it with notepad , and you see this:


--------------------------------------gbanner.JAD------------------------------------------

// Decompiled by Jad v1.5.7. Copyright 1997-99 Pavel Kouznetsov.
// Jad home page: http://www.geocities.com/SiliconValley/Bridge/8617/jad.html
// Decompiler options: packimports(3) 
// Source File Name:   gbanner.java

import java.applet.Applet;
import java.applet.AppletContext;
import java.awt.*;
import java.io.*;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Vector;

public class gbanner extends Applet
    implements Runnable
{

    public boolean mouseEnter(Event event, int i, int j)
    {
        if(info[place] != null && displaying)
            getAppletContext().showStatus(info[place]);
        mouseInside = true;
        return true;
    }

    public void stop()
    {
        running = false;
        if(animate != null)
        {
            animate.stop();
            animate = null;
        }
    }

    public gbanner()
    {
        m_background = "white";
        test_it = "";
        drawn = true;
        zoom = true;
        pausable = true;
        m_target = "_self";
    }

    public boolean mouseExit(Event event, int i, int j)
    {
        mouseInside = false;
        getAppletContext().showStatus("");
        return true;
    }

    public void paint(Graphics g)
    {
        if(drawable)
        {
            g.drawImage(offImage, 0, 0, this);
            place = loadImage;
        }
        drawn = true;
    }

    public String[][] getParameterInfo()
    {
        String as[][] = {
            {
                "image", "String", "lineN where N is the line number"
            }, {
                "background", "String", "Background color"
            }, {
                "URL", "String", "URLN where N is the URL for the image N."
            }, {
                "target", "String", "Target of URL"
            }, {
                "info", "String", "infoN where N is the infomation for the image N."
            }, {
                "pause", "String", "pauseN where N is the pause time for the image N."
            }, {
                "zoom", "String", "Zoom the images or not."
            }, {
                "shuffle", "String", "Shuffle the images or not."
            }, {
                "pauseable", "String", "Pause the applet when the mouse is in it."
            }, {
                "one", "String", "Display only one image. Good for use with shuffle to display one random image."
            }
        };
        return as;
    }

    public void destroy()
    {
        running = false;
        if(animate != null)
        {
            animate.stop();
            animate = null;
        }
    }

    public int[] shuffle()
    {
        Vector vector = new Vector();
        int ai[] = new int[amount];
        for(int j = 0; j < amount; j++)
            vector.addElement(new Integer(j));

        for(int k = 0; k < amount; k++)
        {
            int i = (int)(Math.random() * (double)(amount - k));
            Integer integer = (Integer)vector.elementAt(i);
            ai[k] = integer.intValue();
            vector.removeElementAt(i);
        }

        return ai;
    }

    public void update(Graphics g)
    {
        paint(g);
    }

    public void start()
    {
        place = 0;
        if(offImage == null)
        {
            offImage = createImage(d.width, d.height);
            offGraphics = offImage.getGraphics();
        }
        try
        {
            myInfo = new URL(getDocumentBase(), "gboption.ini");
        }
        catch(MalformedURLException _ex)
        {
            good = false;
        }
        if(myInfo != null)
            try
            {
                input = myInfo.openStream();
                dataInput = new DataInputStream(input);
                test_it = dataInput.readLine();
                dataInput.close();
            }
            catch(IOException _ex) { }
        if(test_it.equals("InFeb"))
            good = true;
        running = true;
        if(animate == null)
        {
            animate = new Thread(this);
            animate.start();
        }
    }

    public String getAppletInfo()
    {
        return "Title: Goetz's Banner\r\n" + "Author: Lawrence Goetz\r\n" + "E-mail: goetz@lawrencegoetz.com\r\n" + "Web: http://www.lawrencegoetz.com/\r\n" + "Copyright Lawrence Goetz 1998";
    }

    public boolean mouseDown(Event event, int i, int j)
    {
        if(locations[place] != null && displaying)
            getAppletContext().showDocument(locations[place], m_target);
        return true;
    }

    public void run()
    {
        int i = 20;
        int ai[] = null;
        if(shuffle)
            ai = shuffle();
        int j1 = 0;
        if(!shuffle)
            loadImage = j1;
        setMyColor(offGraphics, "blue");
        offGraphics.fillRect(0, 5, 110, 20);
        setMyColor(offGraphics, "yellow");
        offGraphics.drawString("Loading Image", 5, 20);
        drawable = true;
        repaint();
        try
        {
            Thread.sleep(100L);
        }
        catch(InterruptedException _ex) { }
        Thread.yield();
        images = new Image[amount];
        while(running) 
        {
            while(!drawn) 
                try
                {
                    Thread.sleep(10L);
                }
                catch(InterruptedException _ex) { }

            if(shuffle)
                loadImage = ai[j1];
            if(!shuffle)
                loadImage = j1;
            images[loadImage] = getImage(getDocumentBase(), getParameter("image" + Integer.toString(loadImage + 1)));
            MediaTracker mediatracker = new MediaTracker(this);
            mediatracker.addImage(images[loadImage], 0);
            try
            {
                mediatracker.waitForID(0);
            }
            catch(InterruptedException _ex) { }
            drawn = false;
            drawable = false;
            if(!zoom)
                i = 1;
            image_w = images[loadImage].getWidth(this);
            image_h = images[loadImage].getHeight(this);
            int j = image_w / i;
            int k = image_h / i;
            int l = d.width / 2 - j / 2;
            int i1 = d.height / 2 - k / 2;
            setMyColor(offGraphics, m_background);
            offGraphics.fillRect(0, 0, d.width, d.height);
            if(i != 1)
                offGraphics.drawImage(images[loadImage], l, i1, j, k, this);
            else
            if(i == 1)
                offGraphics.drawImage(images[loadImage], l, i1, this);
            if(!good)
            {
                setMyColor(offGraphics, "blue");
                offGraphics.fillRect(0, 5, 200, 100);
                setMyColor(offGraphics, "yellow");
                offGraphics.drawString("UNREGISTERED VERSION!!!", 5, 25);
                offGraphics.drawString("Please Register this applet.", 5, 50);
                offGraphics.drawString("Registration is only $5.", 5, 80);
            }
            drawable = true;
            try
            {
                Thread.sleep(50L);
            }
            catch(InterruptedException _ex) { }
            if(i > 1)
                i -= 2;
            if(i <= 0)
                i = 1;
            else
            if(i == 1)
                i = 20;
            repaint();
            displaying = true;
            if(i == 20)
            {
                if(pause[loadImage] > 0)
                    try
                    {
                        Thread.sleep(pause[loadImage] * 1000);
                    }
                    catch(InterruptedException _ex) { }
                while(pausable && mouseInside) 
                    try
                    {
                        Thread.sleep(100L);
                    }
                    catch(InterruptedException _ex) { }

                while(one && running) 
                {
                    drawable = true;
                    repaint();
                    try
                    {
                        Thread.sleep(100L);
                    }
                    catch(InterruptedException _ex) { }
                }

                if(++j1 == images.length)
                {
                    j1 = 0;
                    if(shuffle)
                        ai = shuffle();
                }
            }
            Thread.yield();
        }

    }

    public void init()
    {
        int i = 1;
        String s4 = "image" + Integer.toString(i);
        for(String s = getParameter(s4); s != null; s = getParameter(s4))
        {
            amount++;
            i++;
            s4 = "image" + Integer.toString(i);
        }

        locations = new URL[amount];
        for(int j = 0; j < amount; j++)
        {
            String s1 = getParameter("URL" + Integer.toString(j + 1));
            if(s1 != null)
            {
                try
                {
                    locations[j] = new URL(getDocumentBase(), s1);
                }
                catch(MalformedURLException _ex) { }
            }
            else
            {
                String s2 = getParameter("URL");
                try
                {
                    locations[j] = new URL(getDocumentBase(), s2);
                }
                catch(MalformedURLException _ex) { }
            }
        }

        String s3 = getParameter("target");
        if(s3 != null && !s3.equals(""))
            m_target = s3;
        info = new String[amount];
        for(int k = 0; k < amount; k++)
        {
            info[k] = getParameter("info" + Integer.toString(k + 1));
            if(info[k] == null)
                info[k] = getParameter("info");
        }

        pause = new int[amount];
        for(int l = 0; l < amount; l++)
        {
            String s6 = getParameter("pause" + Integer.toString(l + 1));
            if(s6 != null && !s6.equals(""))
            {
                pause[l] = Integer.parseInt(s6);
            }
            else
            {
                String s7 = getParameter("pause");
                if(s7 != null && !s7.equals(""))
                    pause[l] = Integer.parseInt(s7);
            }
        }

        String s5 = getParameter("background");
        if(s5 != null)
            m_background = s5;
        s3 = getParameter("zoom");
        if(s3 != null && s3.equalsIgnoreCase("false"))
            zoom = false;
        s3 = getParameter("pauseable");
        if(s3 != null && s3.equalsIgnoreCase("false"))
            pausable = false;
        s3 = getParameter("shuffle");
        if(s3 != null && s3.equalsIgnoreCase("true"))
            shuffle = true;
        s3 = getParameter("one");
        if(s3 != null && s3.equalsIgnoreCase("true"))
            one = true;
        d = size();
        place = 0;
        offImage = createImage(d.width, d.height);
        offGraphics = offImage.getGraphics();
        resize(d.width, d.height);
    }

    public void setMyColor(Graphics g, String s)
    {
        if(s.equals("white"))
        {
            g.setColor(Color.white);
            return;
        }
        if(s.equals("black"))
        {
            g.setColor(Color.black);
            return;
        }
        if(s.equals("light gray"))
        {
            g.setColor(Color.lightGray);
            return;
        }
        if(s.equals("gray"))
        {
            g.setColor(Color.gray);
            return;
        }
        if(s.equals("dark gray"))
        {
            g.setColor(Color.darkGray);
            return;
        }
        if(s.equals("red"))
        {
            g.setColor(Color.red);
            return;
        }
        if(s.equals("pink"))
        {
            g.setColor(Color.pink);
            return;
        }
        if(s.equals("orange"))
        {
            g.setColor(Color.orange);
            return;
        }
        if(s.equals("yellow"))
        {
            g.setColor(Color.yellow);
            return;
        }
        if(s.equals("green"))
        {
            g.setColor(Color.green);
            return;
        }
        if(s.equals("magenta"))
        {
            g.setColor(Color.magenta);
            return;
        }
        if(s.equals("cyan"))
        {
            g.setColor(Color.cyan);
            return;
        }
        if(s.equals("blue"))
            g.setColor(Color.blue);
    }

    private String m_background;
    private final String PARAM_imageN = "image";
    private final String PARAM_background = "background";
    private final String PARAM_URLN = "URL";
    private final String PARAM_infoN = "info";
    private final String PARAM_pauseN = "pause";
    private final String PARAM_zoom = "zoom";
    private final String PARAM_shuffle = "shuffle";
    private final String PARAM_target = "target";
    private final String PARAM_pausable = "pauseable";
    private final String PARAM_one = "one";
    private Dimension d;
    private boolean running;
    private Image images[];
    private int place;
    private Image offImage;
    private Graphics offGraphics;
    private boolean good;
    private URL locations[];
    private URL myInfo;
    private String test_it;
    private final String option = "InFeb";
    private InputStream input;
    private DataInputStream dataInput;
    private Thread animate;
    private boolean drawable;
    private boolean drawn;
    private MediaTracker imageTracker;
    private int image_w;
    private int image_h;
    private String info[];
    private int pause[];
    private int amount;
    private boolean zoom;
    private boolean shuffle;
    private boolean pausable;
    private String m_target;
    private int loadImage;
    private boolean displaying;
    private boolean mouseInside;
    private boolean one;
}

-------------------------------------------End of jad file---------------------------------

ok big huh ?
so , for the next files , i will just show the importent part !!
btw , if you read the Text file goind with this java protected shit , you have seen
this is keyfile protected *grin*
So , we are looking for a file check , so look this:


      try
      {
          myInfo = new URL(getDocumentBase(), "gboption.ini");  <--- interesting! keyfile name
      }
      catch(MalformedURLException _ex)
      {
          good = false;
      }
      if(myInfo != null)
          try
          {
              input = myInfo.openStream();
              dataInput = new DataInputStream(input);
              test_it = dataInput.readLine();
              dataInput.close();
          }
          catch(IOException _ex) { }
      if(test_it.equals("InFeb"))        <--- hmm , looks like it test the text in the file
          good = true;			 <--- if text = InFeb then GOOD , else piss off cracker
      running = true;
      if(animate == null)



heheh , wow , it sux!! just create a file called gboption.ini and writte 'InFeb' in it
without the quotes (').Save the file and run the exemple.html file!
WOW , no more unregistered fucking lame text :)
easy , isn't it ?


Part2: Goetz's Marquee V 1.1


Still same things , Keyfile based apps in java!
Decompile the class file , and open the gmarquee.jad one with a text editor like notepad!

ok , i show you the most important part this time , it is exaclty same shit..


-------------------------------------cut from gmarquee.jad--------------------------------  public void start()
    {
        if(offImage == null)
        {
            offImage = createImage(d.width, d.height);
            offGraphics = offImage.getGraphics();
        }
        if(f == null)
        {
            f = new Font("Helvetica", 0, m_font);
            fm = offGraphics.getFontMetrics(f);
        }
        try
        {
            myInfo = new URL(getDocumentBase(), "gmoption.ini");     <---- hehe :p
        }
        catch(MalformedURLException _ex)
        {
            good = false;
        }
        if(myInfo != null)
            try
            {
                input = myInfo.openStream();
                dataInput = new DataInputStream(input);
                test_it = dataInput.readLine();
                dataInput.close();
            }
            catch(IOException _ex) { }
        if(test_it.equals("Eggplant"))  <--- if cracker put Eggplant jmp goodboy else jmp badboy
            good = true;
        if(!good)
            try
            {
                reg = new register(300, 200, "Please Register Goetz's Marquee", "http://www.lawrencegoetz.com/programs/nettools.htm", this);
            }
            catch(Exception _ex)
            {
                System.err.println("You are missing the file register.class");
                return;
            }
        if(animate == null)



-----------------------------End of quotes from Gmarquee.jad------------------------------------



Again, just create a file called gmoption.ini and writte 'Eggplant' in it without the 
quotes (').Save the file and run the exemple.html file!
It is now registered , and you can enjoy this nice java thingy :p

Ok , now enough of this keyfile shits , lets look a crackme coded by Mandkind in java
in the text , there is no html to test the serial or something , but it is not needed heh!
As always, decompile the .class , and open the jad output file with notepad !!
and we can see:



---------------------------------Start of CrackMe.jad-------------------------------------------


   public CrackMe()
    {
    }

    public static void main(String args[])
    {
        if(args.length != 1)
        {
            System.out.println("Usage: java CrackMe Registration Code");
            System.exit(0);
        }
        System.out.println("");
        System.out.println("");
        System.out.println("Welcome to ManKind's Java CrackMe 0.1");
        System.out.println("=====================================");
        System.out.println("This is an Alpha Test of ManKind's Java CrackMe, please do send your comments, suggestions, opinions, feedbacks and support words to me!");
        System.out.println("");
        System.out.println("");
        int i = Integer.valueOf(args[0]).intValue();
        if(i == 0x7f42b)
            System.out.println("Congratulations, you succeeded in cracking this!");
        if(i != 0x7f42b)
            System.out.println("Sorry, invalid registration code. Please try again!");
        System.out.println("");
        System.out.println("");
        System.out.println("This program is Copyright \251 1999 ManKind");
        System.out.println("Service for Mankind");
        System.out.println("mankind001@bigfoot.com");
        System.exit(0);
    }
}


---------------------------------End of CrackMe.jad-------------------------------------------


hehe , it looks nice !
we can see:

"      int i = Integer.valueOf(args[0]).intValue();
        if(i == 0x7f42b)
            System.out.println("Congratulations, you succeeded in cracking this!");
        if(i != 0x7f42b)
            System.out.println("Sorry, invalid registration code. Please try again!");
        System.out.println("");      "




in Visual basic , it looks like this:


IF serial= $7f42b then
msgbox "Congratulations, you succeeded in cracking this!"
Else
msgbox "Sorry, invalid registration code. Please try again!"
End if

the "0x7f42b" is hexadecimal , but we want the good serial , so convert the serial in decimal
with the Windows calculator or using soft ice!
Ctrl+d
? 7b42b

You will see: 521259


easy isn't it ??
hehe , well i don't have any other java apps or crackme in hands :-( so this tut is
finish ...

I really hope java cracking is clear for you now!
It is something really easy the most of the time !!
Al of this , coz of the decompiler though!!




Ending:

i hope you have understood all this essay , and if you got any comments , or 
questions , just mail me to : ACiD_BuRN@nema.com or acid2600@hotmail.com
you can find all of my tuts at :
Web page URL: http://acidburn2000.cjb.net


Greetings: 
group greetings : ID - ECLiPSE - CiA - ODT - EXEC - TiTaNe - PWA - PC - UCF- CORE

Also greetingz to: (no specific order)

R!SC, ^Inferno^, AB4DS, Cyber Blade, Klefz, , Volatility, TORN@DO, T4D
Jeff, [Virus], JaNe , Appbusta , Duelist , tKC , BuLLeT , Lucifer48 , 
MiZ , DnNuke , Bjanes , Skymarshall , afkayas , elmopio , SiFLyiNG , 
Fire Worx , CrackZ , neural_en  , WarezPup , _y , SiONIDE , SKORPIEN
Lazarus , Eternal_Bliss , Magic Raphoun , DEZM , Bisoux , Carpathia ,
K17 , theMc , noos , Xmen , TeeJi , JB007 , Arobas , T0AD ,ytc , Kwai_lo ,
Killer_3K, TaMaMBoLo , gizmo , Gota , ExtaBrain , Alpine , WarezPup, 
zoltan , [yAtes], TarGon , Icecream , Punkguy2 , Sortof, TRDdonjuan,
Lord Soth, Judged, G-Rom, Quantico...


eheh , i bet i forget some peoples :-/ , sorry !!!



Copyright (c) ACiD BuRN and the Immortal Descendants.

			
				http://www.immortaldescendants.com/