Stuxnet (2010) [pdf]
wired.com
wired.com
It was the first time I felt like "wow, those guys, those security researchers, I wanna be one of them". It really opened my eyes to how computer software can be complex, political, puzzling and how an "antivirus" company operates in the backstage. I still remember that one single article as a pivotal point in my life, making me look at software engineering as a career that could also be fun.
[0] http://web.archive.org/web/20190106014001/https://www.wired.... (resorting to Web Archive since the live version isn't opening anymore since Wired updated their website layout)
Is the DEADF007 purpose still unsolved or has subsequent analysis figured it out?