A common algorithm is used for the dictionary tables of all the major web service platforms (Java, ASP.NET, and Apache). In late 2011 a clever attack was released that took advantage of the ubiquity of this hashing algorithm. By sending a single POST message filled with thousands of variables, the hashing function would overload and a server could be tied up processing this single request for as long as an hour. This is a hash denial-of-service (DoS) attack.