Difference between revisions of "Testing for WS HTTP GET parameters/REST attacks (OWASP-WS-005)"

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'''HTTP GET parameters.'''
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{{Template:OWASP Testing Guide v3}}
  
===Brief Summary===
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==Brief Summary==
  
 
Many XML applications are invoked by passing them parameters using HTTP GET queries.
 
Many XML applications are invoked by passing them parameters using HTTP GET queries.
These are sometimes known as “REST-style" Web Services. These Web Services can be attacked by  passing malicious content on the HTTP GET string (e.g. Extra long parameters (2048 chars), SQL statements/injection or OS Injection parameters).
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These are sometimes known as “REST-style" Web Services (REST = Representational State Transfer). These Web Services can be attacked by  passing malicious content on the HTTP GET string (e.g., extra long parameters (2048 chars), SQL statements/injection (or OS Injection parameters).
REST = Representational State Transfer).
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== Description of the Issue ==
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Given that REST Web services are in effect HTTP-In -> WS-Out, attack patterns, they are very similar to regular HTTP attack vectors, discussed throughout the guide. For example, in the following HTTP request with query string ''"/?viewDetail=detail-10293"'', the HTTP GET parameter is ''"detail-10293"''.
  
=== Description of the Issue ===
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==Black Box Testing and example==
Given that Web services REST are in effect HTTP-In -> WS-OUT at attack patterns are very similar to regular HTTP attack vectors, discussed throughout the guide.
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'''Example:'''
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The HTTP request with query string /viewDetail=detail-10293, the HTTP GET parameter is ''detail- 10293''.
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===Black Box Testing===
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Say we had a Web Service which accepts the following HTTP GET query string:
 
Say we had a Web Service which accepts the following HTTP GET query string:
https://www.ws.com/accountinfo?accountnumber=12039475&userId=asi9485jfuhe92
 
  
The resultant response would be similar to:
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<nowiki>https://www.ws.com/accountinfo?accountnumber=12039475&userId=asi9485jfuhe92</nowiki>
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The response would be similar to:
  
 
  <?xml version="1.0" encoding="ISO-8859-1"?>
 
  <?xml version="1.0" encoding="ISO-8859-1"?>
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Try vectors such as:
 
Try vectors such as:
<nowiki>https://www.ws.com/accountinfo?accountnumber=12039475'</nowiki>''' exec master..xp_cmdshell 'net user Vxr pass /Add''' &userId=asi9485jfuhe92
 
  
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<nowiki>https://www.ws.com/accountinfo?accountnumber=12039475'</nowiki>''' exec master..xp_cmdshell 'net user Vxr pass /Add'''&userId=asi9485jfuhe92
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==Grey Box Testing and example==
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Upon the reception of an HTTP request the code should do the following:
  
===Grey Box Testing===
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Check:
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# Maximum and minimum length
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# Validate payload
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# If possible, implement the following data validation stratigies: "exact match", "known good" and "known bad", in this order.
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# Validate parameter names and existence.
  
===References===
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==References==
The OWASP Fuzz vectors list:
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'''Withepapers'''
[http://www.owasp.org/index.php/OWASP_Testing_Guide_Appendix_C:_Fuzz_Vectors]
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* The OWASP [[OWASP_Testing_Guide_Appendix_C:_Fuzz_Vectors|Fuzz vectors]] list

Latest revision as of 18:51, 15 December 2008

OWASP Testing Guide v3 Table of Contents

This article is part of the OWASP Testing Guide v3. The entire OWASP Testing Guide v3 can be downloaded here.

OWASP at the moment is working at the OWASP Testing Guide v4: you can browse the Guide here

Contents


Brief Summary

Many XML applications are invoked by passing them parameters using HTTP GET queries. These are sometimes known as “REST-style" Web Services (REST = Representational State Transfer). These Web Services can be attacked by passing malicious content on the HTTP GET string (e.g., extra long parameters (2048 chars), SQL statements/injection (or OS Injection parameters).

Description of the Issue

Given that REST Web services are in effect HTTP-In -> WS-Out, attack patterns, they are very similar to regular HTTP attack vectors, discussed throughout the guide. For example, in the following HTTP request with query string "/?viewDetail=detail-10293", the HTTP GET parameter is "detail-10293".

Black Box Testing and example

Say we had a Web Service which accepts the following HTTP GET query string:

https://www.ws.com/accountinfo?accountnumber=12039475&userId=asi9485jfuhe92

The response would be similar to:

<?xml version="1.0" encoding="ISO-8859-1"?>
<Account="12039475">
<balance>€100</balance>
<body>Bank of Bannana account info</body>
</Account>

Testing the data validation on this REST web service is similar to generic application testing:

Try vectors such as:

https://www.ws.com/accountinfo?accountnumber=12039475' exec master..xp_cmdshell 'net user Vxr pass /Add&userId=asi9485jfuhe92


Grey Box Testing and example

Upon the reception of an HTTP request the code should do the following:

Check:

  1. Maximum and minimum length
  2. Validate payload
  3. If possible, implement the following data validation stratigies: "exact match", "known good" and "known bad", in this order.
  4. Validate parameter names and existence.

References

Withepapers