MS Innovation Day: A Lap Around Web Application Vulnerabilities by MVP Walter Wong

Lap Around Web Application Vulnerabilities Walter Wong MVP – Visual Developer (Security) walter_wws@hotmail.com http://spaces.live.com/walterwws

Top 10 Web Application vulnerabilities in 2007 1 • Cross-site Scripting (XSS) 2 • Injection Flaws 3 • Malicious File Execution 4 • Insecure Direct Object Reference 5 • Cross Site Request Forgery 6 • Information Leakage and Improper Error Handling 7 • Broken Authentication and Session Management 8 • Insecure Cryptographic Storage 9 • Insecure Communications 10 • Failure to Restrict URL Access Source: http://www.owasp.org/index.php/top_10_2007

Agenda The foundation of attack Advance attack techniques Obfuscation Automated Testing

Foundation of attack Application attack also known as “layer 7 attack” Program is just a set of instruction. Developer is the key protector All input is evil (Writing Secure Code by Michael Howard and David LeBlanc)

SQL Cross- Injection site Scripting Path Traversal 3 basic techniques

SQL Injection Build SQL statement using string concatenation Attacker change the semantics of SQL query Developer prefer string concatenation because is easy but they also known the safer method but requires more thought

Scenario #1 Attacker submit specially crafted input when performing search

SQL Injection

http://www.lowyat.net Date : 12 June 2008

Cross-site Scripting (XSS) How it works? 1. Take input from user 2. Fails to validate input 3. Echoes input directly to web page 4. Done!

Scenario #2 When developer using <%# DataBinder.Eval(Container.DataItem, “Column1”) %> to bind data in Datalist.

Cross-Site Scripting (XSS)

Path Traversal Access files that application not intend to access To read any files in the system Using “dot-dot-slash” to backtrack the folder Example: http://app.com/GetImage.aspx?file=....windowsrepairsam

Scenario #3 To prevent “Resource cannot be found”, developer create a page to check whether the picture file it exist or not. If doesn’t exist it will show the generic image.

Path Traversal

Advance Technique Utilizing the basic attack techniques Able to unveil a lot of privacy information of servers Example: WMI Attack Host File Hijacking

WMI Attack WMI = Windows Management Instrumentation WMI is a essential tools for IT Administrator to manage the servers and workstations Damages: Retrieve server’s information Remotely uninstall application

Scenario #4 Attack retrieve the software installed in web server and uninstall the software.

WMI Attack

Host File Hijacking Windows rely on DNS and Host file to resolve the target IP address Host file location : %windir%system32driversetchosts Damages: Corrupt the host file so it can redirect the data to malicious server

Scenario #5 Attacker redirect the traffic for www.abc.com to different IP address. Imagine a antivirus application refer the wrong IP address to download the latest signature file.

Host File Hijacking

Obfuscation The default .Net assembly format allow developer to disassemble and decompile. Obfuscate is a process to rebuilds the .Net assembly into a new format that is impossible to dissemble, decompile and difficult to understand. Prevent competitors and hackers from getting your source code.

Scenario #6 Attacker download the .Net assembly through Path Traversal attack. He successfully dissemble and decompile the assembly. Attacker now able to view all the logic behind the source code.

Obfuscator

Automated Testing Develop your own testing tools Automate your testing process Visual Studio Tester Edition have a capability to do automated testing

The Dark Side…… Brutal Force attack are using the same technique It is a common attack to “try” out password To prevent such attack, identify the source. MAC Address IP Address Login username

Scenario #7 Develop a simple application to automate the brutal force attack on wireless router.

Automate the task

Steps to Defense Against Attackers Validate both client-side and server-side input Duplicated the validation functions in both client-side and server side NO SQL Injection – use Parameter class in .Net NO XSS – Validate Input, Validate Output (VIVO) Obfuscate your code TODAY! Be innovative and creative in testing

Walter_wws@hotmail.com

Resources Visit My Blog at http://spaces.live.com/walterwws

Resources Visit My Pagecast at http://www.pageflakes.com/walterw

© 2008 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

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MS Innovation Day: A Lap Around Web Application Vulnerabilities by MVP Walter Wong

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MS Innovation Day: A Lap Around Web Application Vulnerabilities by MVP Walter Wong Presentation Transcript