Zack Anderson was one of three MIT students who caused a stir over the summer when they decided to disclose flaws they discovered in the Massachusetts transit authority's "Charlie Card" fare system.

Anderson, Russell "RJ" Ryan and Alessandro Chiesa planned to show off their findings (.pdf) at the Defcon hacker conference in August, prompting the Massachusetts Bay Transportation Authority (MBTA) to seek a temporary gag order until the problems could be fixed.

A US District court judge eventually dissolved the gag order, but the incident rekindled debate over whether flaws should be publically disclosed before the affected vendor has a chance to fix them.

In this Q&A, Anderson explains the surprise he and his peers felt over the MBTA's response, why he thinks the flaw exposure was necessary and what the lesson is for future researchers.

What was the main motivation for hacking into the MBTA's ticketing system?

It started as a class project. We wanted to do a security analysis of an important system which, if the security were compromised, could lead to a number of issues. We settled on subway fare collection systems and saw that the system integrator that makes Boston's fair collection system also makes collection systems around the world. We figured that if we were to find vulnerabilities in the Boston system they might well apply to others.

Were you surprised by how easily you were able to punch through the system?

Yeah. What was most surprising, though, was the fact that they already have a lot of infrastructure in place to build a much more secure system but they don't have the software to leverage that hardware.

Were you and your fellow students surprised by the resistance you ran into with the MBTA after you announced your discovery?

Absolutely. We did contact the MBTA and said we wanted to sit down with them, go over what we had found and recommend some ways to fix it so they could go back to the integrator and say'this is what we'd like done.' We thought that would go well, since we were out to help them. What happened instead was a lot of animosity from the start. The funny thing is that we eventually did sit down with them and everything was fine. The person we sat down with thanked us and was mad at the system integrator for making a flawed system that the MBTA had spent millions of dollars on.