According to Zscaler, botnets are currently the leading source of malicious Internet traffic targeting enterprises.

"Over the past 30 days, botnets have accounted for nearly 80 percent of the security blocks within ZScaler’s network," writes Threatpost's Brian Donohue.

"In a distant second place among security blocks, malicious URLs accounted for almost 15 percent, and in a somewhat less distant third place, antivirus accounted for just fewer than four percent of blocks," Donohue writes.

Go to "Research: Botnets, the Most Prevalent Threat in the Enterprise" to read the details.

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