Marcin Kleczynski (born November 1, 1989) is the chief executive officer (CEO) and co-founder of American Internet security company, Malwarebytes. After a period working as a computer repair technician and being involved in forums in the mid-2000s, Kleczynski co-founded Malwarebytes with Bruce Harrison in January 2008. By 2014, Malwarebytes had treated over 250 million computers worldwide, with a range of popular products including Malwarebytes Anti-Malware, Malwarebytes Anti-Exploit, and more recently, advanced anti-ransomware package Endpoint Security. Kleczynski was named one of Forbes Magazine's "30 Under 30" Rising Stars of Enterprise Technology in 2015.