Barracuda Networks has launched a countersuit against Trend Micro just a week after it appeared that a breakthrough had been reached in the ongoing patent battle.

The countersuit, filed in the Court for the Central District of California, alleges that Trend Micro infringed on three patents owned by Barracuda Networks.

Barracuda is seeking damages and an injunction on sales of the allegedly infringing products.

The original claim alleges that Barracuda infringed on a Trend Micro patent through its use of the open source ClamAV security software.

"The reality is that Trend Micro is asking Barracuda Networks to pay for the use of the free and open source ClamAV software," said Dean Drako, president and chief executive of Barracuda.

"We have asserted all along that Trend Micro's actions are unjust and could have serious implications for the open source community and other free and open source projects."

Barracuda claims in its countersuit that Trend Micro infringed on US Patents 7,093,287, 7,093,294 and 7,103,913 which were purchased by Barracuda from IBM.

The patents detail methodologies for virus protection, spam, web filtering and intrusion detection.

"Barracuda Networks would prefer to focus on innovation, not litigation, so it is unfortunate that we must defend ourselves with a countersuit," said Drako. "Innovation will lead to a safer internet; litigation will not."

If successful, Barracuda has promised to contribute all of the net proceeds to the open source community.