Charles 4.5.1逆向工程/破解

Charles 4.5.1逆向破解

前两天剁了Burp Pro 2.1.04破解版，今天写写如何破解Charles 4.5.1。该文主要以逆向与软件安全为方向编写（作者scz）。你也可参阅Charles破解版/破解工具找到你想要的。

Charles如果未注册，启动时有个10s倒计时，30天试用期，每运行30分钟就自动退出。

Charles缺省是用其自带JDK 11启动的:

C:\Program Files\Charles\jdk\

正常注册流程是:

启动Charles->Help->Register Charles->输入Registered Name/License Key

这里会弹一个对话框，有Register、Cancel两个按钮。如何找到Register按钮对应的代码？假设Register按钮用到了JButton，在按钮上显示"Register"这个字符串时会用到javax.swing.AbstractButton.setText()，查看它的调用栈回溯，或许就能定位Register按钮对应的代码。

对javax.swing.AbstractButton.setText()设断，命中时:

[1] javax.swing.AbstractButton.setText (AbstractButton.java:297), pc = 0 [2] javax.swing.AbstractButton.init (AbstractButton.java:2,128), pc = 6 [3] javax.swing.JButton.<init> (JButton.java:131), pc = 18 [4] javax.swing.JButton.<init> (JButton.java:104), pc = 3 [5] com.xk72.charles.gui.frames.RegisterFrame.<init> (null), pc = 45 [6] com.xk72.charles.gui.menus.HelpMenu$4.actionPerformed (null), pc = 8 [7] javax.swing.AbstractButton.fireActionPerformed (AbstractButton.java:1,967), pc = 83

爽到了，关注"com.xk72.charles.gui.frames.RegisterFrame.class"。

比起Burp Pro 2.1.04，Charles 4.5.1的混淆程度太弱，说是一马平川不为过。据说Charles早期版本没有混淆过，比如4.0.2，我以前没接触过。

Charles 4.5.1反编译

C:\Program Files\Charles\lib\charles.jar

com.xk72.charles.gui.frames.RegisterFrame.class

public class RegisterFrame extends JDialog { private final JTextField tName; private final JTextField tSerial; /* * Register按钮 */ private final JButton bRegister; /* * Cancel按钮 */ private final JButton bCancel; public RegisterFrame ( Frame paramFrame ) { super( paramFrame, true ); setTitle( "Register Charles" ); this.tName = new JTextField( 20 ); this.tSerial = new JTextField( 20 ); this.bRegister = new JButton( "Register" ); this.bCancel = new JButton( "Cancel" ); Container localContainer; (localContainer = getContentPane()).setLayout( new MigLayout( "wrap,fill", "[label][fill,grow]" ) ); localContainer.add( new JLabel( "Registered Name:" ) ); localContainer.add( this.tName ); localContainer.add( new JLabel( "License Key:" ) ); localContainer.add( this.tSerial ); localContainer.add( this.bCancel, "tag cancel,split 2,span,center" ); localContainer.add( this.bRegister, "tag ok" ); this.bCancel.addActionListener( new gTDF( this ) ); /* * 在此添加Register按钮的处理代码，据此关注 * * com.xk72.charles.gui.frames.PeRA.class */ this.bRegister.addActionListener( new PeRA( this ) ); pack(); if ( paramFrame != null ) { ( paramFrame = new Point( paramFrame.getLocation() ) ).translate( 20, 20 ); setLocation( paramFrame ); } getRootPane().setDefaultButton( this.bRegister ); getRootPane().getInputMap(1).put( KeyStroke.getKeyStroke( "ESCAPE" ), "escape" ); getRootPane().getActionMap().put( "escape", new RegisterFrame.3( this ) ); }

com.xk72.charles.gui.frames.PeRA.class

import com.xk72.charles.YQUd; final class PeRA implements ActionListener { PeRA( RegisterFrame paramRegisterFrame ) { } public final void actionPerformed ( ActionEvent paramActionEvent ) { paramActionEvent = RegisterFrame.tEdg( this.tEdg ).getText().trim(); String str = RegisterFrame.TryJ( this.tEdg ).getText().trim(); if ( ( paramActionEvent.length() > 0 ) && ( str.length() > 0 ) ) { Object localObject; /* * 为了注册成功，YQUd.tEdg()必须返回null。据此关注 * * com.xk72.charles.YQUd.class */ if ( ( localObject = YQUd.tEdg( paramActionEvent, str ) ) != null ) { /* * 注册失败 */ ExtendedJOptionPane.tEdg( this.tEdg, localObject, "Charles Registration", 2 ); return; } /* * 注册成功，显示注册信息 */ ExtendedJOptionPane.tEdg( this.tEdg, "Thank you for registering. Charles will now close. Please start Charles again to continue.", "Charles Registration", 1 ); ( localObject = CharlesContext.getInstance() ).getConfiguration().getRegistrationConfiguration().setName( paramActionEvent ); ( ( CharlesContext )localObject ).getConfiguration().getRegistrationConfiguration().setKey( str ); ( ( CharlesContext )localObject ).exit( 0, true ); } } }

YQUd.class共有5个public method:

1. public com.xk72.charles.YQUd();
2. public static boolean tEdg();
3. public static void TryJ();
4. public static java.lang.String NCuT();
5. public static java.lang.String tEdg(java.lang.String, java.lang.String);

com.xk72.charles.YQUd.class

public final class YQUd { private static YQUd TryJ; /* * 为true时表示已注册 */ private boolean NCuT; public YQUd () { this.NCuT = false; this.Rarr = "Unregistered"; } /* * 为true时表示已注册 */ public static boolean tEdg () { YQUd var0 = TryJ; return TryJ.NCuT; } public static void TryJ () { TryJ = new YQUd(); } /* * 这是要显示到"About Charles"的内容 */ public static String NCuT () { YQUd var0 = TryJ; switch( gTDF.tEdg[var0.aqrV.ordinal()] ) { case 1: return var0.Rarr; case 2: return var0.Rarr + " - Site License"; case 3: return var0.Rarr + " - Multi-Site License"; default: return var0.Rarr; } } /* * 务必让本函数返回null */ public static String tEdg ( String var0, String var1 ) { YQUd var3; try { var3 = new YQUd( var0, var1 ); } catch ( LicenseException var2 ) { return var2.getMessage(); } TryJ = var3; return null; }

编辑YQUd.java:

package com.xk72.charles; public final class YQUd { /* * 只Patch这5个public method，其他private的扔掉即可 */ public YQUd () { } /* * 为true时表示已注册 */ public static boolean tEdg () { return( true ); } public static void TryJ () { } /* * 这是要显示到"About Charles"的内容，这个内容任意 */ public static String NCuT () { return "Anyting - Site License"; } /* * 务必让本函数返回null */ public static String tEdg ( String var0, String var1 ) { return null; } }

编译YQUd.java得到新的YQUd.class，替换charles.jar中的YQUd.class。

比起Burp，破解Charles实在是太简单了。要点是定位YQUd.class，每个版本混淆后的名字都不一样，需要重新定位。由于已经讲清楚原理，以后破解都不需要动态调试设断，直接在反编译器中静态定位。

作者：scz