Fortinet has filed a petition with the U.S. Patent and Trademark Office to re-examine a security patent held by Trend Micro.
The Trend Micro patent in question, 5,623,600, covers virus detection and removal processes. The patent has led to a few skirmishes in the security industry, notably a battle between Trend Micro and Barracuda Networks. Fortinet says its petition identifies prior art that makes Trend Micro’s patent invalid.
Fortinet has tussled with Trend Micro before. Trend Micro sued Fortinet in 2004 and the two companies settled a patent dispute in 2006. The legal peace didn’t last long. Fortinet sued Trend Micro again—following a 2008 and 2009 duel—in January because Fortinet considered the patent it licensed in 2006 to be invalid. Fortinet also alleged that Trend Micro threatened its customers.