Insight Into Web Services Security Testing

At present, the web services have turned into an integral portion of the mobile and web applications. Because the millions of people are using the business and mobile applications, web services are becoming one of the major target or attack vectors of the hackers. Unfortunately, most of the testers today are not bothered about the web service popularities, its recent advancements and demanding testing methodologies & tools. On the other hand, most methodologies that are active in the current organizations either don’t work appropriately or poorly designed to meet the real-world vulnerabilities. Furthermore, there is no proper environment for evaluating the tools and attack techniques of the web services. Well, this article is going to address some useful information about the web services security testing and factors to consider in the implementation of the same.

Reasons Why Hackers Target Web Services

Web service provides the hacker a secondary route to attack the web application. Since in most of the cases, the web services are created in a way to integrate the remote systems into the processes or data of the business. Hence, these services allow direct access for the hacker. The hackers are possibly competent enough to exploit the vulnerabilities present in the web service and thereby bypass the application controls. In addition, most developers, as well as administrators, aren’t focusing on the security challenges of the web services. The penetration testers often found that the web services are developed or installed outside the scope of web application protection.

Web Service Testing

Web services applications are systems that are facilitating the business to inter-operates and are progressing at an unparalleled rate. They are visible on the net similar to any other service. The framework of the web services employs the HTTP protocol as the standard web application in combination with the following technologies:

  • WSDL (Web Service Description Language) -describes the service interfaces

  • SOAP (Simple Object Access Protocol) – offers a means for communication between the client applications and web services

  • UDDI (Universal Description, Discovery & Integration) – employed to register & publish Web services

The vulnerabilities found in the web services are analogous to other common vulnerabilities like information disclosure, SQL injection, and leakage. In addition, web services also comprise unique XML/parser oriented vulnerabilities.

Accurately testing a web service involves something more than using a tool in WSDL to check whether there are security problems. However, the security communities are not putting much effort and time in this area. The traditionally documented testing methodologies and testing techniques not capable enough to meet the ever-evolving vulnerabilities and recent real-world threats to the web services. In addition, currently, the tester has no proper testing environment to test the new tools & techniques and enhance their skills. There is no practical way for the testers to test the new methodologies and tools. Such condition makes the web service testing mystery.

The Issues with Testing The Web Application

The majority of the testing tools or web service available in the market is meant only for the quality assurance, not for security testing. Similarly, the penetration tests aren’t scoped adequately to add the associated web services. In case they are scoped properly, most of the testers possess no idea on how to start web service testing. Once the testers initiate the process, they used to get more confusions especially in case the web service is employing custom or proprietary technology like homegrown authentication mechanisms. Unfortunately, time, which could be used upon evaluating for vulnerabilities and flaws often are used upon constructing interfaces and tools to test the security of web services.

Another problem in the testing the novel web services like Windows Communication Foundation (WCF) is that currently, we have no proper tools to test them properly. Because the WCF web services are designed to employ TCP binding as opposed to the less secure BasicHTTPBinidng. The testing tools, which support the WCF protocols are generally commercial based and mainly offer functional testing.

OWASP Web Service Testing Methodology

The OWASP testing guide v4 states the methodology for the web service testing. They are as follows:

  • WS Information Gathering – Involves determining the WS entry point as well as communication schema

  • Testing WSDL – Once the WS entry point is determined, we can test the WSDL

  • XML structure Testing – If the XML is not formed well, that shall fail once parsed on the server side; hence that should be formed to function properly. The structure of the XML requires being tested to ensure that it runs the entire XML message thoroughly in a serial way to evaluate the XML well-formedness.

  • XML Content Level Testing – Generally the content-level attacks focus on the server that hosting a web service and any apps, which are used by the service.

  • HTTP GET Parameters / REST Testing – Several XML applications are raised by sending them as parameters via HTTP GET queries. Attackers can pass malevolent content via the HTTP GET string to attack the web services.

  • Naughty SOAP Attachments – The risks present in the processing the server attachments and redeployment of the file to the clients. This section tests the attack vectors for the web servers, which accept attachments.

Web Service Testing Checklist

The following list describes the checklist that the testers need to consider while performing the web service security testing.

  • Pre-Assessment

  • Information Gathering

  • Testing Phase

web services information gatheriing

black box information gathering

web services testing phase

Hope the above information would provide you an idea about the recent posture of web services security testing. In the forthcoming years, it will be essential for the security tester to work with the application developers to determine the threat vector, which should be integrated into the continuing threat models for testing web services security



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