A new version of the Zeus financial malware uses peer-to-peer technology to improve its defenses.

The bug previously relied on a series of randomly generated domain names to receive updates, according to an article Computerworld published Wednesday. The malware's operators would register those domain names and use them to distribute updates to Zeus.

But "a few weeks ago I've noticed that no new … domain names have been registered by the criminals," Swiss security expert Roman Hssy wrote on his blog.

The new version, though to be a custom variant made by one fraud gang, uses a peer-to-peer system to receive updates by connecting to other infected computers — communicating with about 100,000 unique Internet Protocol addresses in 24 hours, the article said. The researcher was able to view this traffic because the Zeus variant relied on a single domain name to receive instructions and transmit stolen data, the article said.