I have been encountering more and more clients needing their API (usually REST) endpoints tested for vulnerabilities and wanted to reach out to see if anyone has some recommendations beyond what I have been doing.

I am very familiar with the REST security cheat sheet from OWASP and have built a number of API's myself so I know to look for HTTP methods, CSRF, Sensitive data disclosure, input validation, SSL configs, etc. but am I missing anything? What techniques is everyone doing to go above and beyond to find an API vulnerability / exploit? Any recommended tools that do the job better than a good old intercepting proxy and curl?

  • 1
    That cheat sheet is pretty good. I've had most results from injection, session management, and insecure direct object references. For SOAP services, SOAPui is pretty good, but I don't know an equivalent for REST.
    – paj28
    Feb 6, 2014 at 1:45

2 Answers 2


My favorite RESTful client is httpie (from Python sources). Easily get it via easy_install httpie or pip install httpie. There are a few REST clients/debuggers as Firefox add-ons (search via addons.mozilla.org).

While at a certain company, I recall using a WebInspect feature called "custom parameters" against RESTful Web Services, such as the REST-WS demo in the Maven Security Web Security Dojo virtual machine or the OWASP GoatDroid Project's use of JAX-RS. If you also have access to the Fortify SecurityScope product, you can use use it to automatically create a WADL which in turn can be consumed by WebInspect RT. When testing large apps (e.g., greater than two million lines of code), this can be especially useful -- voice of experience here.

When you look at the SecToolMarket report, most of the tools that have under 9 input vectors cannot handle RESTful Web Services very well, and even the best ones (Burp Suite Professional, NTOSpider, IBM Appscan, etc) don't have a clear path to testing these interfaces/APIs. This is often why you'd want to use a tool like httpie (or curl) through them as an intercepting proxy, along with the appropriate API documentation (probably preferably in WADL format).


You are missing one important thing:

giving end users training/information on data security

Phishing & Social Engineering are your biggest risk factors in any deployment

  • 1
    Totally agree on user training and awareness. The question is really about technical controls and testing suggestions as that is really all I have control over in the pen testing world.
    – jmbmxer
    Feb 5, 2014 at 22:57

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