Web Service Security Testing Cheat Sheet

Last revision (mm/dd/yy): 08/4/2015

Web Services Security Testing Cheat Sheet Introduction

As Web Services are incorporated into application environments, having a good checklist while performing security assessments can help a penetration tester better identify web service related vulnerabilities and associated risk.

Purpose

This document is intended to be an easy to use checklist while performing assessments against web services. The penetration tester is advised to incorporate this into his or her corporate testing methodology as a supplemental checklist or is free to use this checklist as the sole testing guideline.

Checklist

Pre-Assessment

• For a Black Box assessment, at the very least, the penetration tester will need the Web Service Description Language (WSDL) file
  
• For a Grey Box assessment, the penetration tester will need sample requests for each method employed by the web service(s), along with the Web Service Description Language (WSDL) file

Information Gathering

• Black Box
  
  • Google hacking
    
    • Inurl:jws?wsdl
      
    • Inurl:asmx?wsdl
      
    • Inurl:aspx?wsdl
      
    • Inurl:ascx?wsdl
      
    • Inurl:ashx?wsdl
      
    • Inurl:dll?wsdl
      
    • Inurl:exe?wsdl
      
    • Inurl:php?wsdl
      
    • Inurl:pl?wsdl
      
    • Inurl:?wsdl
      
    • Filetype:jws
      
    • Filetype:asmx
      
    • Filetype:ascx
      
    • Filetype:aspx
      
    • Filetype:ashx
      
    • Filetype:dll
      
    • Filetype:exe
      
    • Filetype:php
      
    • Filetype:pl
      
  • WSDL file contents
    
    • Methods
      
    • Data Types
      
  • UDDI
    
    • Web Service Discovery (If no WSDL provided)
      
  • Authentication Type Discovery
    
  • REST vs. SOAP
    
• Grey Box
  
  • WSDL file contents
    
    • Methods
      
    • Data Types
      
  • Sample Requests
    
    • Methods
      
    • Data Types
      
    • Types of Information Being Requested/Consumed
      
  • Authentication Type Discovery
    
  • REST vs. SOAP

Testing Phase

• Baseline Tests
  
  • Normal Request(s)/Response(s) for Each Method
    
• Automated Tests
  
  • Tools
    
    • SoapUI Pro
      
    • IBM AppScan
      
    • HP Webinspect
      
    • WSBang
      
    • WSMap
      
• Vulnerability Discovery
  
  • Debug output
    
  • Fuzzing
    
  • XSS
    
  • SQLi
    
  • Malformed XML
    
  • Malicious Attachment/File Upload
    
  • Xpath Injection
    
  • Improper Boundary Checking
    
  • XML Bomb (DoS)
    
  • Basic Authentication
    
  • SAML/OAuth/OpenID authentication
    
    • Authentication based attacks
      
      • Replay attacks
        
      • Session fixation
        
      • XML Signature wrapping
        
      • Inadequate session timeout settings
        
    • Improper implementation
      
  • SSL/TLS Use
    
  • Host Cipher Support
    
  • Valid Certificate
    
  • Protocol Support
    
  • Hashing Algorithm Support
    
  • Deprecated cipher suites that are offered
    
    • External resources
      
      • SSL Labs
        
    • Internal resources
      
      • SSLscan
        
  • Authorization Bypass
    
  • Schema Implementation Weaknesses
    
  • Non-encoded Output
    
• Manual Tests
  
  • Tools
    
    • Soap UI Free
      
    • Burp Suite Pro
      
      • Suggested extensions:
        
        • SAML Editor
          
        • SAML Encoder / Decoder
          
        • WSDL Wizard
          
        • Wsdler
          
    • SOA Client
      
    • WSDigger (deprecated)
      
  • Vulnerability Discovery
    
    • Debug output
      
  • Fuzzing
    
    • XSS
      
    • SQLi
      
    • Malformed XML
      
    • Malicious Attachment/File Upload
      
    • Xpath Injection
      
    • Improper Boundary Checking
      
    • XML Bomb (DoS)
      
    • Basic Authentication
      
    • SSL/TLS Failback

Testing REST Based Web Services

There is already a great cheat sheet on how to properly test the security of REST based web services. You can find the guide at the following location:
[1] https://www.owasp.org/index.php/REST_Assessment_Cheat_Sheet

Testing Summary

While using automated tools, the penetration tester will need to validate all reported findings manually and perform due diligence false positive analysis for each vulnerability reported. During the manual phase of testing, the penetration tester will look for the existence of vulnerabilities missed by the automated tools and will validate automated tool output as necessary.

References

[2] http://www.securestate.com/Insights/Documents/WhitePapers/Dont-Drop-the-SOAP-Whitepaper.pdf
[3] http://resources.infosecinstitute.com/web-services/
[4] http://resources.infosecinstitute.com/web-services-penetration-testing-part-1/
[5] http://resources.infosecinstitute.com/web-services-penetration-testing-part-2-automated-approach-soapui-pro/
[6] http://resources.infosecinstitute.com/web-services-pen-test-part-3-automation-appscan-webinspect/
[7] https://www.youtube.com/watch?v=J-uO0ELZ2rk
[8] http://www-01.ibm.com/support/docview.wss?uid=swg21404788
[9] https://www.owasp.org/index.php/Web_Service_Security_Cheat_Sheet
[10] http://www.pushtotest.com/blogs/60-the-cohen-blog/697-web-security-test-solutions-with-testmaker-and-soapui.html
[11] https://msdn.microsoft.com/en-us/library/ff650168.aspx
[12] http://www.soapui.org/security-testing/overview-of-security-scans.html
[13] https://www.owasp.org/index.php/Web_Application_Security_Testing_Cheat_Sheet
[14] http://resources.infosecinstitute.com/web-services-pen-test-part-4-manual-testing-soa-client/
[15] http://projects.webappsec.org/w/page/13247002/XML%20Entity%20Expansion
[16] https://www.owasp.org/index.php/Testing_WSDL_%28OWASP-WS-002%29
[17] https://www.youtube.com/watch?v=QLKM4USUlZs
[18] https://www.youtube.com/watch?v=RHIkb9yEV1k
[19] https://www.usenix.org/system/files/conference/usenixsecurity12/sec12-final91.pdf
[20] http://resources.infosecinstitute.com/saml-oauth-openid/
[21] http://blog.sendsafely.com/post/69590974866/web-based-single-sign-on-and-the-dangers-of-saml
[22] https://www.usenix.org/system/files/conference/usenixsecurity12/sec12-final91.pdf

Additional Resources

Below are resources to help the tester learn and refine their ability to effectively test various web services.

Virtual Machines

• OWASP Mutillidae
  
• PenTester Lab: Axis2 Web Service and Tomcat Manager
  
• DVWS
  
• OWASP WebGoat
  

Online Resources

• [23] http://www-01.ibm.com/support/docview.wss?uid=swg21288823
  
• [24] http://zero.webappsecurity.com/
  
• [25] https://media.blackhat.com/bh-us-11/Johnson/BH_US_11_JohnsonEstonAbraham_Dont_Drop_the_SOAP_WP.pdf
  
• [26] http://www.securitytube.net/video/11695
  
• [27] http://www.securitytube.net/video/8462
  
• [28] http://www.securitytube.net/video/1113
  
• [29] http://resources.infosecinstitute.com/web-services-pen-test-part-4-manual-testing-soa-client/
  
• [30] https://www.owasp.org/index.php/REST_Assessment_Cheat_Sheet

Primary Author

• Michael Born

Contributing Editors/Authors

• John Rogers
• Zac Fowler
• Fred Donovan
• Rob Temple
• Andrew Freeborn
• Sai Uday Shankar Korlimarla
• Robert Nordstrom
• Justin Williams