package org.owasp.webgoat.lessons;
import java.io.IOException;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CharsetEncoder;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.List;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEParameterSpec;
import org.apache.ecs.Element;
import org.apache.ecs.ElementContainer;
import org.apache.ecs.html.A;
import org.apache.ecs.html.B;
import org.apache.ecs.html.IMG;
import org.apache.ecs.html.Input;
import org.apache.ecs.html.P;
import org.apache.ecs.html.TD;
import org.apache.ecs.html.TR;
import org.apache.ecs.html.Table;
import org.owasp.webgoat.session.ECSFactory;
import org.owasp.webgoat.session.WebSession;
import org.owasp.webgoat.util.HtmlEncoder;
/***************************************************************************************************
*
*
* This file is part of WebGoat, an Open Web Application Security Project utility. For details,
* please see http://www.owasp.org/
*
* Copyright (c) 2002 - 2007 Bruce Mayhew
*
* This program is free software; you can redistribute it and/or modify it under the terms of the
* GNU General Public License as published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
* even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with this program; if
* not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
* 02111-1307, USA.
*
* Getting Source ==============
*
* Source for this application is maintained at code.google.com, a repository for free software
* projects.
*
* For details, please see http://code.google.com/p/webgoat/
*
* @author Jeff Williams <a href="http://www.aspectsecurity.com">Aspect Security</a>
* @created October 28, 2003
*/
public class Encoding extends LessonAdapter
{
public final static A ASPECT_LOGO = new A().setHref("http://www.aspectsecurity.com")
.addElement(
new IMG("images/logos/aspect.jpg").setAlt("Aspect Security").setBorder(0).setHspace(0)
.setVspace(0));
private final static String INPUT = "input";
private final static String KEY = "key";
// local encoders
private static sun.misc.BASE64Decoder decoder = new sun.misc.BASE64Decoder();
private static sun.misc.BASE64Encoder encoder = new sun.misc.BASE64Encoder();
// encryption constant
private static byte[] salt = { (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
(byte) 0x00, (byte) 0x00 };
/**
* Returns the base 64 decoding of a string.
*
* @param str
* Description of the Parameter
* @return Description of the Return Value
* @exception IOException
* Description of the Exception
*/
public static String base64Decode(String str) throws IOException
{
byte[] b = decoder.decodeBuffer(str);
return (new String(b));
}
/**
* Description of the Method
*
* @param c
* Description of the Parameter
* @return Description of the Return Value
* @exception IOException
* Description of the Exception
*/
public static String base64Decode(char[] c) throws IOException
{
return base64Decode(new String(c));
}
/**
* Description of the Method
*
* @param c
* Description of the Parameter
* @return Description of the Return Value
*/
public static String base64Encode(char[] c)
{
return base64Encode(new String(c));
}
/**
* Returns the base 64 encoding of a string.
*
* @param str
* Description of the Parameter
* @return Description of the Return Value
*/
public static String base64Encode(String str)
{
byte[] b = str.getBytes();
return (encoder.encode(b));
}
/**
* Description of the Method
*
* @param b
* Description of the Parameter
* @return Description of the Return Value
*/
public static String base64Encode(byte[] b)
{
return (encoder.encode(b));
}
/**
* Description of the Method
*
* @param s
* Description of the Parameter
* @return Description of the Return Value
*/
protected Element createContent(WebSession s)
{
ElementContainer ec = new ElementContainer();
try
{
String userInput = s.getParser().getRawParameter(INPUT, "");
String userKey = s.getParser().getStringParameter(KEY, "");
Table table = new Table();
TR tr = new TR();
tr.addElement(new TD("Enter a string: "));
Input input = new Input(Input.TEXT, INPUT, userInput);
tr.addElement(new TD().addElement(input));
table.addElement(tr);
tr = new TR();
tr.addElement(new TD("Enter a password (optional): "));
Input key = new Input(Input.TEXT, KEY, userKey);
tr.addElement(new TD().addElement(key));
table.addElement(tr);
tr = new TR();
Element b = ECSFactory.makeButton("Go!");
tr.addElement(new TD().setAlign("center").setColSpan(2).addElement(b));
table.addElement(tr);
ec.addElement(table);
ec.addElement(new P());
Table t = new Table();
t.setWidth("100%");
t.setBorder(0);
t.setCellSpacing(1);
t.setCellPadding(4);
String description;
t.addElement(makeTitleRow("Description", "Encoded", "Decoded"));
description = "Base64 encoding is a simple reversable encoding used to encode bytes into ASCII characters. Useful for making bytes into a printable string, but provides no security.";
// t.addElement( makeDescriptionRow( description ) );
t.addElement(makeRow(description, base64Encode(userInput), base64Decode(userInput)));
// t.addElement( makeSpacerRow() );
description = "Entity encoding uses special sequences like &amp; for special characters. This prevents these characters from being interpreted by most interpreters.";
t.addElement(makeRow(description, HtmlEncoder.encode(userInput), HtmlEncoder.decode(userInput)));
description = "Password based encryption (PBE) is strong encryption with a text password. Cannot be decrypted without the password";
t.addElement(makeRow(description, encryptString(userInput, userKey), decryptString(userInput, userKey)));
description = "MD5 hash is a checksum that can be used to validate a string or byte array, but cannot be reversed to find the original string or bytes. For obscure cryptographic reasons, it is better to use SHA-256 if you have a choice.";
t.addElement(makeRow(description, hashMD5(userInput), "Cannot reverse a hash"));
description = "SHA-256 hash is a checksum that can be used to validate a string or byte array, but cannot be reversed to find the original string or bytes.";
t.addElement(makeRow(description, hashSHA(userInput), "N/A"));
description = "Unicode encoding is...";
t.addElement(makeRow(description, "Not Implemented", "Not Implemented"));
description = "URL encoding is...";
t.addElement(makeRow(description, urlEncode(userInput), urlDecode(userInput)));
description = "Hex encoding simply encodes bytes into %xx format.";
t.addElement(makeRow(description, hexEncode(userInput), hexDecode(userInput)));
description = "Rot13 encoding is a way to make text unreadable, but is easily reversed and provides no security.";
t.addElement(makeRow(description, rot13(userInput), userInput));
description = "XOR with password encoding is a weak encryption scheme that mixes a password into data.";
t.addElement(makeRow(description, xorEncode(userInput, userKey), xorDecode(userInput, userKey)));
description = "Double unicode encoding is...";
t.addElement(makeRow(description, "Not Implemented", "Not Implemented"));
description = "Double URL encoding is...";
t.addElement(makeRow(description, urlEncode(urlEncode(userInput)), urlDecode(urlDecode(userInput))));
ec.addElement(t);
}
catch (Exception e)
{
s.setMessage("Error generating " + this.getClass().getName());
e.printStackTrace();
}
if (getLessonTracker(s).getNumVisits() > 3)
{
makeSuccess(s);
}
return (ec);
}
/**
* Convenience method for encrypting a string.
*
* @param str
* Description of the Parameter
* @param pw
* Description of the Parameter
* @return String the encrypted string.
*/
public static synchronized String decryptString(String str, String pw)
{
try
{
PBEParameterSpec ps = new javax.crypto.spec.PBEParameterSpec(salt, 20);
SecretKeyFactory kf = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
Cipher passwordDecryptCipher = Cipher.getInstance("PBEWithMD5AndDES/CBC/PKCS5Padding");
char[] pass = pw.toCharArray();
SecretKey k = kf.generateSecret(new javax.crypto.spec.PBEKeySpec(pass));
passwordDecryptCipher.init(Cipher.DECRYPT_MODE, k, ps);
byte[] dec = decoder.decodeBuffer(str);
byte[] utf8 = passwordDecryptCipher.doFinal(dec);
return new String(utf8, "UTF-8");
}
catch (Exception e)
{
return ("This is not an encrypted string");
}
}
/**
* Convenience method for encrypting a string.
*
* @param str
* Description of the Parameter
* @param pw
* Description of the Parameter
* @return String the encrypted string.
* @exception SecurityException
* Description of the Exception
*/
public static synchronized String encryptString(String str, String pw) throws SecurityException
{
try
{
PBEParameterSpec ps = new javax.crypto.spec.PBEParameterSpec(salt, 20);
SecretKeyFactory kf = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
Cipher passwordEncryptCipher = Cipher.getInstance("PBEWithMD5AndDES/CBC/PKCS5Padding");
char[] pass = pw.toCharArray();
SecretKey k = kf.generateSecret(new javax.crypto.spec.PBEKeySpec(pass));
passwordEncryptCipher.init(Cipher.ENCRYPT_MODE, k, ps);
byte[] utf8 = str.getBytes("UTF-8");
byte[] enc = passwordEncryptCipher.doFinal(utf8);
return encoder.encode(enc);
}
catch (Exception e)
{
return ("Encryption error");
}
}
/**
* Gets the category attribute of the Encoding object
*
* @return The category value
*/
protected Category getDefaultCategory()
{
return Category.INSECURE_STORAGE;
}
/**
* Gets the hints attribute of the HelloScreen object
*
* @return The hints value
*/
public List<String> getHints(WebSession s)
{
List<String> hints = new ArrayList<String>();
hints.add("Enter a string and press 'go'");
hints.add("Enter 'abc' and notice the rot13 encoding is 'nop' ( increase each letter by 13 characters ).");
hints.add("Enter 'a c' and notice the url encoding is 'a+c' ( ' ' is converted to '+' ).");
return hints;
}
/**
* Gets the instructions attribute of the Encoding object
*
* @return The instructions value
*/
public String getInstructions(WebSession s)
{
return "This lesson will familiarize the user with different encoding schemes. ";
}
private final static Integer DEFAULT_RANKING = new Integer(15);
protected Integer getDefaultRanking()
{
return DEFAULT_RANKING;
}
/**
* Gets the title attribute of the HelloScreen object
*
* @return The title value
*/
public String getTitle()
{
return ("Encoding Basics");
}
/**
* Returns the MD5 hash of a String.
*
* @param str
* Description of the Parameter
* @return Description of the Return Value
*/
public static String hashMD5(String str)
{
byte[] b = str.getBytes();
MessageDigest md = null;
try
{
md = MessageDigest.getInstance("MD5");
md.update(b);
} catch (NoSuchAlgorithmException e)
{
// it's got to be there
e.printStackTrace();
}
return (base64Encode(md.digest()));
}
/**
* Returns the SHA hash of a String.
*
* @param str
* Description of the Parameter
* @return Description of the Return Value
*/
public static String hashSHA(String str)
{
byte[] b = str.getBytes();
MessageDigest md = null;
try
{
md = MessageDigest.getInstance("SHA-256");
md.update(b);
} catch (NoSuchAlgorithmException e)
{
// it's got to be there
e.printStackTrace();
}
return (base64Encode(md.digest()));
}
/**
* Description of the Method
*
* @param hexString
* Description of the Parameter
* @return Description of the Return Value
*/
public static String hexDecode(String hexString)
{
try
{
if ((hexString.length() % 3) != 0) { return ("String not comprised of Hex digit pairs."); }
char[] chars = new char[hexString.length()];
char[] convChars = new char[hexString.length() / 3];
hexString.getChars(0, hexString.length(), chars, 0);
for (int i = 1; i < hexString.length(); i += 3)
{
String hexToken = new String(chars, i, 2);
convChars[i / 3] = (char) Integer.parseInt(hexToken, 16);
}
return new String(convChars);
} catch (NumberFormatException nfe)
{
return ("String not comprised of Hex digits");
}
}
/**
* Description of the Method
*
* @param asciiString
* Description of the Parameter
* @return Description of the Return Value
*/
public static String hexEncode(String asciiString)
{
char[] ascii = new char[asciiString.length()];
asciiString.getChars(0, asciiString.length(), ascii, 0);
StringBuffer hexBuff = new StringBuffer();
for (int i = 0; i < asciiString.length(); i++)
{
hexBuff.append("%");
hexBuff.append(Integer.toHexString(ascii[i]));
}
return hexBuff.toString().toUpperCase();
}
/**
* The main program for the Encoding class
*
* @param args
* The command line arguments
*/
public static void main(String[] args)
{
try
{
String userInput = args[0];
String userKey = args[1];
System.out.println("Working with: " + userInput);
System.out.print("Base64 encoding: ");
System.out.println(base64Encode(userInput) + " : " + base64Decode(userInput));
System.out.print("Entity encoding: ");
System.out.println(HtmlEncoder.encode(userInput) + " : " + HtmlEncoder.decode(userInput));
System.out.print("Password based encryption (PBE): ");
System.out.println(encryptString(userInput, userKey) + " : " + decryptString(userInput, userKey));
System.out.print("MD5 hash: ");
System.out.println(hashMD5(userInput) + " : " + "Cannot reverse a hash");
System.out.print("SHA-256 hash: ");
System.out.println(hashSHA(userInput) + " : " + "Cannot reverse a hash");
System.out.print("Unicode encoding: ");
System.out.println("Not Implemented" + " : " + "Not Implemented");
System.out.print("URL encoding: ");
System.out.println(urlEncode(userInput) + " : " + urlDecode(userInput));
System.out.print("Hex encoding: ");
System.out.println(hexEncode(userInput) + " : " + hexDecode(userInput));
System.out.print("Rot13 encoding: ");
System.out.println(rot13(userInput) + " : " + userInput);
System.out.print("XOR with password: ");
System.out.println(xorEncode(userInput, userKey) + " : " + xorDecode(userInput, userKey));
System.out.print("Double unicode encoding is...");
System.out.println("Not Implemented" + " : " + "Not Implemented");
System.out.print("Double URL encoding: ");
System.out.println(urlEncode(urlEncode(userInput)) + " : " + urlDecode(urlDecode(userInput)));
} catch (Exception e)
{
e.printStackTrace();
}
}
/**
* Description of the Method
*
* @param value1
* Description of the Parameter
* @param value2
* Description of the Parameter
* @param description
* Description of the Parameter
* @return Description of the Return Value
*/
private TR makeRow(String description, String value1, String value2)
{
TD desc = new TD().addElement(description).setBgColor("#bbbbbb");
TD val1 = new TD().addElement(value1).setBgColor("#dddddd");
TD val2 = new TD().addElement(value2).setBgColor("#dddddd");
TR tr = new TR();
tr.addElement(desc);
tr.addElement(val1);
tr.addElement(val2);
return tr;
}
/**
* Description of the Method
*
* @param value1
* Description of the Parameter
* @param value2
* Description of the Parameter
* @param description
* Description of the Parameter
* @return Description of the Return Value
*/
private TR makeTitleRow(String description, String value1, String value2)
{
TD desc = new TD().addElement(new B().addElement(description));
TD val1 = new TD().addElement(new B().addElement(value1));
TD val2 = new TD().addElement(new B().addElement(value2));
desc.setAlign("center");
val1.setAlign("center");
val2.setAlign("center");
TR tr = new TR();
tr.addElement(desc);
tr.addElement(val1);
tr.addElement(val2);
return (tr);
}
/**
* Description of the Method
*
* @param input
* Description of the Parameter
* @return Description of the Return Value
*/
public static synchronized String rot13(String input)
{
StringBuffer output = new StringBuffer();
if (input != null)
{
for (int i = 0; i < input.length(); i++)
{
char inChar = input.charAt(i);
if ((inChar >= 'A') & (inChar <= 'Z'))
{
inChar += 13;
if (inChar > 'Z')
{
inChar -= 26;
}
}
if ((inChar >= 'a') & (inChar <= 'z'))
{
inChar += 13;
if (inChar > 'z')
{
inChar -= 26;
}
}
output.append(inChar);
}
}
return output.toString();
}
/**
* Description of the Method
*
* @param str
* Description of the Parameter
* @return Description of the Return Value
*/
public static String unicodeDecode(String str)
{
// FIXME: TOTALLY EXPERIMENTAL
try
{
ByteBuffer bbuf = ByteBuffer.allocate(str.length());
bbuf.put(str.getBytes());
Charset charset = Charset.forName("ISO-8859-1");
CharsetDecoder decoder = charset.newDecoder();
CharBuffer cbuf = decoder.decode(bbuf);
return (cbuf.toString());
} catch (Exception e)
{
return ("Encoding problem");
}
}
/**
* Description of the Method
*
* @param str
* Description of the Parameter
* @return Description of the Return Value
*/
public static String unicodeEncode(String str)
{
// FIXME: TOTALLY EXPERIMENTAL
try
{
Charset charset = Charset.forName("ISO-8859-1");
CharsetEncoder encoder = charset.newEncoder();
ByteBuffer bbuf = encoder.encode(CharBuffer.wrap(str));
return (new String(bbuf.array()));
} catch (Exception e)
{
return ("Encoding problem");
}
}
/**
* Description of the Method
*
* @param str
* Description of the Parameter
* @return Description of the Return Value
*/
public static String urlDecode(String str)
{
try
{
return (URLDecoder.decode(str, "UTF-8"));
} catch (Exception e)
{
return ("Decoding error");
}
}
/**
* Description of the Method
*
* @param str
* Description of the Parameter
* @return Description of the Return Value
*/
public static String urlEncode(String str)
{
try
{
return (URLEncoder.encode(str, "UTF-8"));
} catch (Exception e)
{
return ("Encoding error");
}
}
/**
* Description of the Method
*
* @param input
* Description of the Parameter
* @param userKey
* Description of the Parameter
* @return Description of the Return Value
*/
public static synchronized char[] xor(String input, String userKey)
{
if ((userKey == null) || (userKey.trim().length() == 0))
{
userKey = "Goober";
}
char[] xorChars = userKey.toCharArray();
int keyLen = xorChars.length;
char[] inputChars = null;
char[] outputChars = null;
if (input != null)
{
inputChars = input.toCharArray();
outputChars = new char[inputChars.length];
for (int i = 0; i < inputChars.length; i++)
{
outputChars[i] = (char) (inputChars[i] ^ xorChars[i % keyLen]);
}
}
return outputChars;
}
/**
* Description of the Method
*
* @param input
* Description of the Parameter
* @param userKey
* Description of the Parameter
* @return Description of the Return Value
*/
public static synchronized String xorDecode(String input, String userKey)
{
try
{
String decoded = base64Decode(input);
return new String(xor(decoded, userKey));
} catch (Exception e)
{
return "String not XOR encoded.";
}
}
/**
* Description of the Method
*
* @param input
* Description of the Parameter
* @param userKey
* Description of the Parameter
* @return Description of the Return Value
*/
public static synchronized String xorEncode(String input, String userKey)
{
return base64Encode(xor(input, userKey));
}
public Element getCredits()
{
return super.getCustomCredits("", ASPECT_LOGO);
}
}