ATLANTA, GA. — The number of “zombies”, or computers that are used for distribution of spam and phishing email, has surged by 21 percent recently, according to CipherTrust.

The Atlanta-based provider of messaging security solutions also said that spam is up recently by some 20 percent.

According to CipherTrust research, 64 percent of spam servers are based in Taiwan. Another 23 percent are in the U.S. and 3 percent are in China. CipherTrust estimates that there are nearly 300,000 zombie machines.

The company also reported that graphics-based messages are being used to avoid anti-spam tools.

For more details about CipherTrust’s research, see: research.ciphertrust.com