6a96547ef0
git-svn-id: http://webgoat.googlecode.com/svn/branches/webgoat-6.0@485 4033779f-a91e-0410-96ef-6bf7bf53c507
87 lines
3.4 KiB
HTML
87 lines
3.4 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
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<title>Solution Lab SQL Injection Stage2</title>
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<link rel="stylesheet" type="text/css"
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href="lesson_solutions/formate.css">
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</head>
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<body>
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<p><b>Lesson Plan Title:</b> How to Perform a SQLInjection</p>
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<p><b>Concept / Topic To Teach:</b><br />
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SQL injection attacks represent a serious threat to any database-driven
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site. The methods behind an attack are easy to learn and the damage
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caused can range from considerable to complete system compromise.
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Despite these risks, an incredible number of systems on the internet are
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susceptible to this form of attack.</p>
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<p>Not only is it a threat easily instigated, it is also a threat
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that, with a little common-sense and forethought, can easily be
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prevented.</p>
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<p>It is always good practice to sanitize all input data, especially
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data that will used in OS command, scripts, and database queiries, even
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if the threat of SQL injection has been prevented in some other manner.
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</p>
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<p><b>General Goal(s):</b><br />
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For this exercise, you will perform SQLInjection attacks. You will also
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implement code changes in the web application to defeat these attacks.</p>
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<b>Solution:</b><br />
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To prevent a SQLInjection you can use "Parametreized Queries". This kind of
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query makes it possible to use every input of an user as a parameter.
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In this lesson you have to change org.owasp.webgoat.lessons.SQLInjection.Login.java
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The query execution in the method login looks like this:<pre><code>
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String query = "SELECT * FROM employee WHERE userid = " + userId + " and password = '" + password + "'";
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// System.out.println("Query:" + query);
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try
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{
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Statement answer_statement = WebSession.getConnection(s)
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.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);
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ResultSet answer_results = answer_statement.executeQuery(query);
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etc...
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</code></pre>
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<p>
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To paramerize the Query you have to replace the userinput with questionmarks:<br/>
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<code>String query = "SELECT * FROM employee WHERE userid = ? and password = ?";</code><br/>
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</p>
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<p>
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Now follows the try block with the getConnection method:<br/>
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<code>
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try <br/>
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{<br/>
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Connection connection = WebSession.getConnections(s);
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</code></p>
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<p>
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The next step is to do a so called "PrepareStatement":<br/>
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<code>PreparedStatement statement = connection.prepareStatement(query, ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);
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</code><br/></p>
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<p>
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Now that the query is prepared we have to add the parameters to the query:<br/>
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<code>
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statement.setString(1, userId);<br/>
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statement.setString(2, password);<br>
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</code>
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</p>
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<p>
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We are ready to execute the query!<br/>
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<code>
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ResultSet answer_results = statement.executeQuery();</code>
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</p>
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<p>Putting everything together results in:<br/>
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<pre><code>
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String query = "SELECT * FROM employee WHERE userid = ? and password = ?";
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try
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{
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Connection connection = WebSession.getConnections(s);
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PreparedStatement statement = connection.prepareStatement(query, ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);
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statement.setString(1, userId);
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statement.setString(2, password);
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ResultSet answer_results = statement.executeQuery();
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etc...
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</code></pre>
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</body>
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</html> |