I was assessing an application. The application was properly sanitizing all the characters which have special meaning for SQL Injection attack. So SQL Injection was not possible in the application. But then again I came across few search modules in the application where it was taking input of part numbers to proceed. I entered single quote(') and the application was perfectly filtering it returning "Parts can't be found". Then out of curiosity I entered '%' character and observed the response. Now the application stuck into the loop of the search continuously searching.The two things I deduced from it: 1. The application was using LIKE query to search matching terms. 2. This can be used to perform a DoS by overloading the database. The % and _ qualifier is often overlooked by developers to filter as its not so devastating as other characters. They are used for matching 0 or more characters and single character respectively. $ searhterm = mysql _real_escape...