I'm black-box pen testing a colleague's website for common vulnerabilities (mainly concerned with OWASP's top 10).
I've found a SQL injection vulnerability in a form since the use of special characters in one of the form field's values returns errors. The error specifies that an incorrect number of parameters were provided to some internal function - I suspect, given the purpose of the form, that some particularly complex query sits behind it.
I'm struggling to get any response other than this error. I've tried a browser tool to profile the query hoping it would paint a picture of what the query looked like ready for demonstration of how it can be exploited but it failed to identify a vulnerability at all.
How can I get a clearer picture of what the query looks like? Or is this entirely subjective and specific to this case?
An example answer I'd be after is a way of injecting SQL that, no matter where it sits, can be relied upon to test for vulnerability.
Note: If needs be I can simply outline the fact that I've found a potential vector, but I'd like to be able to explain the extent to which it may be exploited.