The Sobig Worm was a computer worm that infected millions of Internet-connected, Microsoft Windows computers in August 2003. Although there were indications that tests of the worm were carried out as early as August 2002, Sobig.A was first found in the wild in January 2003. Sobig.B was released on May 18, 2003. It was first called Palyh, but was later renamed to Sobig.B after anti-virus experts discovered it was a new generation of Sobig. Sobig.C was released May 31 and fixed the timing bug in Sobig.B. Sobig.D came a couple of weeks later followed by Sobig.E on June 25. On August 19, Sobig.F became known and set a record in sheer volume of e-mails.