question: What were researchers in 2011 able to use as a successful attack vector ?
answer: a malicious compact disc in a car 's stereo system
turker_answer: Researchers were able to use a malicious compact disc in a car 's stereo system as a successful attack vector in 2011 .
rule-based: Researchers in 2011 able to use as a successful attack vector were a malicious compact disc in a car 's stereo system .